Sugar adds a sweet taste to coffee, not a sour taste.  Sourness and sweetness are rather separate tastes! Different flavours will to some extent interact with each other, and individual preference and taste have something to do with this, but there are particular causes of certain flavours.

Sourness is a perception of acidity. In high enough quantities, sugar can overwhelm the perception of acidity (e.g., cola has a pH ~2.5, but doesn't taste sour because the perception is overwhelmed by sugar/sweetness; see also this Seasoned Advice question on sugar reducing perception of sourness). I don't see how sugar could be the cause of sourness (i.e., sugar is not acidic). EDIT: That said, it might be the case that this is a temporal situation. Sugar reduces the perception of sourness, but it could be the case this change is temporary: For example, if the sweetness (sugar) dissipates more quickly than the sourness (acids), you might be left with "more sourness than sweetness" in the aftertaste after some time. That is, you're left with "un-maksked" residual sourness which, though present all along, is more perceptible after the sugar has dissipated. However, all of this is entirely speculation; I have no justification for this, and haven't found any supporting information.

Sweetness is perceived by the presence of sugar (and/or other chemicals that happen to interact in similar ways with sweetness perception). Sugar will also impact mouthfeel.

Bitterness is separate also; see this question on salt and bitterness in coffee.

I don't think there are any chemical changes to the sugar happening in this case.


Here's a few more things to add to @fredley's answer.

Since the water is going to be in contact with the grounds for a longer time (1- using greater volume of water, and 2- Chemex filter will be slower) you're going to get more of the bitter notes that you get (in general) by using a longer brewing time. Acidity will be offset somewhat by the bitterness. I find Chemex to be like a filter-coffee version of the body of a French Press preparation, though with no sediment. Compared to the throughput of V60 filters, @fredley hit it on the nose.

Though you are asking about taste specifically, there are other factors.

Like @fredley said, the filter paper in Chemex is much thicker and water drains through it significantly more slowly. You'll probably want to use a coarser grind (and very even grind) than you would for V60 or Melitta-style filters. Fines are the enemy of Chemex, causing the filter to clog and welling (see this question about "welling up" in a Chemex for more on that). Certainly use the best burr grinder you can and don't delay in the pouring action.

Technique is "more important" (read as: "finicky") with Chemex, I think, than other pour-over systems. See preparation guides such as from Chemex itself, or Blue Bottle, or Stumptown, or search for others.


Optimal moka pot size for flavor extraction?

I would assume that size doesn't matter - if the amount of water is proportionally the same then the steam pressure should also be the same, regardless of the size.

But it seems to be much more complicated than that, and part of your answer probably lies in the research paper entitled "Experimental investigation of steam pressure coffee extraction in a stove-top coffee maker" published in volume 29 of Applied Thermal Engineering, which states:

  Despite its well-established usage, the moka has never been the
  subject of detailed analysis, which led to a series of unclear
  descriptions or misinterpretations concerning its functioning...

That is if you can understand the thermodynamics, though the study itself seems to be a bit inconclusive. One of the closing statements is interesting:

  The quantity of dry air can influence both temperature and flow rate,
  thus affecting final extract quality, and it is meant to be the
  subject of further studies

In the end, though, even the researchers decided that the moka is a bit of an enigma ("...a popular, yet mysterious, device, which so much diverges from other coffee-brewing methods"), so I don't know that you'll find any better answers outside of your own stove-top trials...


Is there a name for this Americano/Long Black Variation?

I mostly drink Americano's  at my favorite coffee roaster, Kaladi Brothers Coffee, ( barista's take a two week training before they are allowed to pull shots for customers ) but occasionally i get a Stretched Lungo. ( French Press Exclusively at home )

Lungo

The link will educate you as to the particulars of the Lungo.

  Both lungos and Americanos are made using an espresso machine and
  water. Which makes you ask ‘Is a lungo an Americano?’. The method of
  making both these coffees sounds the same, but there is a big
  difference. When you make a lungo, all of the water is brewed and it
  generally comes out shorter than an Americano.

  When you make an Americano you add the water after the espresso has
  been pulled from the espresso machine. Americanos also usually come in
  larger cups so you can add as much water as you like to the coffee.

  Lungos should be served in a slightly smaller cup because you don’t
  need to add any water after making it. But if you really like, no one
  will probably judge you if you do!

  Both coffees are made with ground coffee and roughly the same amount
  of water. So you’d expect them to taste the same right? Wrong. Adding
  the water after the espresso has been pulled gives you a weaker
  flavored coffee. Having the water pass through the ground coffee
  granules, as they do in a Lungo, gives you a much stronger flavored
  coffee. Great for those of you who like a strong dark coffee to kick
  start your day!


Could you list healthy, unsweetened coffee flavouring syrups?

The brand MiniSyrup seems to meet your requirements. From their website,

  SUGAR/SWEETENER/CALORIE FREE. Unlike the big bottles of syrup that are crammed with sugar or artificial sweeteners like sucralose and aspartame, MiniSyrup Flavor Shots are the first completely unsweetened flavoring made to flavor your favorite beverages like brewed coffee, hot chocolate, lattes, fountain sodas, tea and more. This gives you complete control over not only the flavor in your beverage, but also your sweetness. [1]

They don't seem to have nutrition information on their website, but myfitnesspal lists the nutrition information for some of their flavors. I'm not sure of the validity, but as you mentioned in a comment you can reach out to MiniSyrup for more information.


Using just a filter without a pour-over to brew coffee

It is certainly possible to avoid using a cone, and I have also done this in a pinch. Though it works, there is no real benefit to using a bare filter (that is, using a paper filter without a filter-holding cone or other device) as far as the brew/outcome is concerned (other than the obvious, trivial facts of less equipment and not having to clean the cone). There are other reasons to not use a cone, and there are also a few downsides.

The main downside is that paper filters are quite flimsy, especially certain brands and types (e.g., Hario V-cones are very thin as compared to thick, almost fabric-like Chemex). They are meant to be used with a supporting cone or basket. With support, they hold together nicely. Without support, they can easily rip, be otherwise damaged, or collapse when filled with water. The consequences are natural: contamination of brewed coffee with grounds, spilled near-boiling water, or other mess.

One might argue that you have better control over the speed or length of infusion, but the coffee will not drain as well or as quickly. You can precisely control the length of water/grounds contact with reasonable pouring methods. The ridges on the cone filter (like this or that question) help to wick the coffee away from the filter so that it drains better. You can also find cones that have a drain plug (one example), so that you can steep the grounds for some time before draining, but I don't believe in that either. No matter what, I argue there's no benefit to a bare filter for this reason either.

That said, there are reasonable ways to use a bare filter. I sometimes use a bare filter for cold-brewing coffee without other equipment: I use a large basket-style filter (arbitrary example) with some grounds, then tied up with a piece of kitchen string into a small sachet like a tea bag, then submerged in a jar of water (see other cold-brew questions, and my problems with same). However, I still have to be very careful to prevent the filter from tearing when removing it from the brewed coffee.

Your friend is clever and plucky for sure; however, I don't think your friend's method is going to catch on at your local coffee shop as the next fancy brew method.


In terms of taste, what is the correct way to produce a full cup of coffee using an AeroPress?

My personal preference is to just add a bit of water to top my cup off.  I do not use the inverted method, and by adding additional water during the brewing (since I tend to get just a bit of drippage during brewing) I tend to end up with pretty close to a full cup.

However, if you are looking for a much stronger (pseudo espresso) cup, the second method may be for you.  It has only really the drawback of using an additional sum of coffee and filter.

I would not recommend using the 3rd method.  At that point you are just headed to over extracted grounds and a less desirable (by most people) cup of coffee.

To sum up, you are looking at producing a cup sized quantity of good coffee with method one, a cup sized quantity of Aerpresso with the second and a cup sized quantity of likely over extracted coffee with method three.  Any of these may be fine depending on what you are trying to achieve.


Stainless steel moka pot with a crema valve for espresso-like crema

My wife and I moved to our new house and we have an induction hob installed there.

We used our brikka(s) a lot and loved the results.

We bought a 4 cup musa for the time being but compared to the brikka it tasted like fermented horse urine.

So I decided to experiment:
Apparently the head from our 2 cup brikka fits the bottom of the 4 cup musa.
It worked! The results are fantastic.
I am going to purchase a 6 cups musa and see if it fits our 4 cup brikka.

The thread on the musa is a bit longer but it doesn't matter: just screw it hard until it locks to put pressure on the seal.

Use just the boiler tank from the musa and all the rest from the brikka as the coffee funnel filter of the musa doesn't have a rubber seal needed for the higher pressure.
Don't put too much water (fill the amount that matches the head. Not the tank)

Good luck!


How should I start a coffee export business?

As another dimension, I see a few trends that you might wish to consider.

Green beans. More people are getting into home roasting, and green (processed but un-roasted) beans are the vehicle. Also, green beans store better for longer time (e.g., freezing) so you can capture a particularly good "year" or crop of beans for a longer period of time. Even whole, unprocessed cherries might be an interesting notion.
Skins and pulp. People make beverages out of the (usually discarded) fruit skin and pulp, called cascara, qishr, or other names. These are difficult to find dried, and perhaps impossible to find fresh.
Direct marketing. Another trend is (broadly) the "farm-to-table" strategy, where roasters or cafes will purchase beans directly from farmers. There might be good business in brokering "direct" deals like this, by helping responsible farmers with good beans get good prices by selling directly to the end user (e.g., a local roaster) instead of through an aggregator or warehouse. You could seek out some exceptional beans with unique qualities and get those farmers into the specialty direct trade market.

Just a perspective from a "consumer" standpoint.


How long is brewed coffee fresh for and what does that blinking light mean at Starbucks?

The blinking light means it has been sitting there for 30 mins.

Starbucks Baristas do in fact brew coffee every 15 mins and are supposed to dump the coffee when the light blinks.

source: a starbucks barista


What is the easiest way to make coffee from beans at home without a device/machine?

For a single cup of coffee, an Aeropress is hands-down the easiest manual coffee brewer around, including cleanup afterwards. I use mine every day.

If you're wanting to make more than one cup at a time, an appropriate sized moka stove-top would be the way to go.


Bulletproof Coffee: how to blend butter well

I have been drinking Bulletproof coffee since 2012 now, so made a few of them. Originally I made a BIG mistake of just stirring butter in the coffee with coconut oil or MCT Oil. You can see how horrible the oil slick looked with an old video I did years ago https://www.youtube.com/watch?v=rap-spa3RfI

What I have found is that you basically need a high speed blender. Vitamix or Blendtec are two brand names Dave has suggested. My wife and I use one called Magimix and it revolutionised how the coffee looks and tastes. So speed is the key. I haven't found a difference by adding the butter or oil in a certain order or way into the blender.


Changing Coffee makes me change grinder level

Expanding comment into a (possible) answer...

On the topic of different beans in a burr grinder: I find that my (admittedly cheap) burr grinder "chokes" on darker-roast beans. When I put dark roast beans into the grinder, the chute gets clogged with coffee grounds more quickly (as compared to lighter-roasted beans). I have a timer-based auto-shutoff model, and much less grounds come out when the grinder is "clogged" in this way. I attribute this clogging to the oil on the surface of the beans that is somehow "sticky" and more prevalent on darker roast beans, but I'm not certain. This article from Coffee Geek talks about cleaning more frequently for darker roast beans, as does this review from Seattle Coffee Gear, as does this one from Coffee Review.

On the topic of espresso pulled from these grounds: This is tricky and I'm really just speculating. Perhaps it's a similar situation: your darker-roast beans respond to tamping differently than your lighter-roast beans. If you're tamping hard and the grounds are clumping together somehow, you might be getting some channeling (resulting in uneven extraction); this could cause a more "watery" shot. You might be able to see evidence of this in the puck after you pull the shot, or you might be able to see it while pulling the shot if you use a naked (bottomless) portafilter. This article from Home-Barista talks about a too-quick extraction being paired with grind flaws; are you seeing that? It also discusses various other flaws and corrections, too various to summarize here.


Is coffee blocking the body from absorbing nutrients?

In a collaborative study at Creighton University in Nebraska and the University of Miami, Florida, researchers showed that caffeine may interfere with vitamin D absorption. The results, published in the "Journal of Steroid Biochemistry and Molecular Biology," demonstrated that the higher the level of caffeine, the more it interfered with vitamin D absorption. The study suggested that caffeine did this by reducing the expression of vitamin D receptors on osteoblasts in the body -- the cells responsible for producing bone.

http://www.direct-ms.org/pdf/VitDGenScience/Caffeine%20Vit%20D%20receptor%2007.pdf


How many plants are needed to brew a cup of coffee?

It all boils down to three questions:
1) Yield = How much did you get from the grounds?
2) Strength = How much ended up in the cup?
3) Ratio = What did you get there?

Yield: Yield pertains to how much soluble you took from the coffee grounds. Ground coffee has something between 27-30% of its mass being soluble, that is, stuff you can dissolve in water. If you kept boiling and boiling coffee grounds in water, eventually you’d get everything that the grounds have to give. Above 22-24%, however, and you’ve essentially reached too far or squeezed too hard, because unpleasant flavors will emerge. Below 18%, and you’re not getting enough out of the coffee, at worst, leaving the coffee with underdeveloped flavors or simply wasting coffee. So it sort of answers the question, “How much did you get from the grounds?”

Strength: Pertains to how much of the final brew is coffee, and how much is water. SCAA Golden Cup says 1.15-1.35% brew strength is a desirable zone to the most number of people, though we espresso-lovers tend to like a bit more… something like 1.3-1.5% brew strength. Over 1.5, up to 2.0% or more, and you’re in the “heavy, thick” coffee zone. Simply put,“How much ended up in the cup?”

Ratio: Simply, grams per liter. It provides one of the major answers to the question that Yield and Strength might ask, that is, “How did you get there?” Perhaps the most easy-to-remember ratio is 60g/L, or 60 grams of coffee for every one liter of water. The fact that you can make a balanced, pleasing, delicious cup of coffee at 60 g/L should give any barista pause when they’re finding that they’re using 80 grams or more per liter when they’re making coffee. Is it “wrong” to make coffee at 90 g/L? No… but is the additional 50% of coffee yielding an additional 50% of coffee quality, compared to the barista down the street making superb coffee at 60 g/L?

For the assistance of common men like me,

Then, to clarify the actual number, if Arabica then 1 - 1.5 pounds per cycle and if Robusta 2 - 2.75 pounds. And then you can calculate the rest. ;)

Sourced from http://portafilter.net.


Why would anyone want to hand grind their coffee?

Hand grinders will work without electricity.

You can generally get a conical hand grinder cheaper than you can get an electric one.

They also create less noise than a electric grinder.

Hand grinders will generally produce less heat than an electric (may affect bean flavor).

Many grinders are lighter and smaller than electric ones. They are portable and can easily be packed for use when traveling.

As to the consistency, a conical grinder (electric or manual) will generally create a more consistent grind than a electric blade "grinder".  Electric blade grinders tend to produce dust and boulders.  I know because I use one at work daily and I can see the inconsistency in the grind, but it doesn't bother me that much.  At home, my burr grinder creates a much more consistent grind.


The Bialetti two Cup stove top produces 100ml of coffee. That is in fact much more than two average espressos. A double shot pulled from an espresso machine would have between 40ml and 60ml.
Your Brikka should thus produce roughly two double shots of espresso. Well it is not actually espresso, but that's a whole different topic.
As far as I know there is only one "marker", which is actually the pressure valve. You should fill the water slightly below the valve. Then you'll get the 100ml.


Make my coffee stronger without equipment

I see only one possibility to make your turkish brew stronger and that is using more coffee beans per serving. You are using boiling water and long extraction time so almost everything from the coffee gets extracted leaving you this only option to make it stronger.


How does coconut milk change the taste of coffee?

I recently tried that (trying to make Bulletproof Coffee) with homemade coconut-milk and it's awesome.

The benefits on focusing are amazing (I'm a programmer & I really feel that) with coffee. I tried that with (normal) butter and another one just with (homemade) almond milk + coconut milk + drip coffee (Chemex)

I'm planning on buying some market coconut-oil, but it's too expensive. I really recommend it to you. Also if you blend it (to mix everything more consistent) it gives you a latte feel.


Normally in a drip coffee machine the 'brew' mode is where the water in the reservoir is boiled/heated and dripped over the ground coffee, before passing through the filter and into the jug. The 'keep warm' part is usually a hot plate under the jug which heats the jug from below, keeping the coffee warm.

My drip coffee machine doesn't allow you to switch it to one mode or the other, you just switch it on and it pumps the water through the filter until its empty - there is a floating switch in the bottom so it knows when there is no more water left, and the hot plate is always on.

I assume that your drip coffee machine works in the same way but has separate controls for the brew and keep warm features. Switching the 'keep warm' feature back on isn't going to harm anything - I'd question the quality of the coffee after 2+ hours sitting on a hot plate though.


I typically buy the giant water jugs that they use for office water coolers. They sell them at nearly all grocery stores and compared to coffee, it's pretty inexpensive. I'd say if it starts taking you more than 20 minutes to move the water by hand, then congratulations on your success, and it's time to buy a filter. If you filter, you'll have the overhead of maintaining the filter and ensuring whatever water supply you have is being filtered well enough, but until then -- just buy it from higher end drinking water sources in large jugs or bottles.


What are the heath risks associated with grinding coffee beans a year after their sell by date?

Normally, the main reason that roasted coffee has a shelf life is its freshness. If the package is properly closed it is mostly safe. Your concern should be its flavor which should be faded away already.

However, you must also think about the mold that may cover the beans. Mold may grow on coffee beans or ground coffee in time. It may cause allergic reactions according to this site or even more. This site includes a guide how to remove mold from coffee beans -however this method affects the flavor.

Maybe a physician could be more helpful about the health effects of mold.


What does strong, mild, very strong mean with respect to coffee?

It usually refers to how long the coffe was roasted as roasting give certain taste in beans.

So it's taste indicator. Mild is very light, sometimes called washed-down (as some places try to pass medium strength as mild by diluting it with water). It should have almost no dry aftertaste (I think you mean that by bitterness). It would also be not so acidic.
Strong coffe is the one that people usually ad milk or sugar as it most dry, acidic, and toasted taste. Brew itself will also have oily/rainbow film on surface.

Light coffes (so mild or any that was toasted shorter than 10 minutes) have the largest amount of caffeine. But that also depend on beans type (Arabica, robusto and so on)


What was the minimum amount of grind that gave you a decent enough quality of coffee in an Aeropress?

I think you'll have to do the experiment to find out.

Measure the beans by weight rather than volume. A digital scale that resolves to 0.1 gram would suffice.

Use a binary search in order to converge on a result with as few trials as possible. E.g. if a reference scoop holds 8 grams, test 4 grams, then if that's too weak, split the difference to 6 grams, and so on. In only 5 trials you'll be able to get an answer to the nearest 0.25 grams; 6 trials to the nearest 0.125 grams.

If your goal is to use the minimum coffee to achieve acceptable taste, think ahead about how to judge if a sample taste is acceptable and how much time to wait between tastings for your mouth to clear. If your goal is to use the minimum code without noticeably changing the taste, use the triangle test.

Control the other brewing variables as tightly as you can: grind size, brewing water temperature (with a thermometer), water volume in the press and in bypass (Americano), brewing time, stirring amount, ... I think the most sensitive factors are water temperature and grind size -- and of course the batch of beans.

Please do report back!


To what temperature do coffee grounds need to be freezed at, after getting wet?

The standard refrigerator temperature most official websites assume are around 4C. Yes, there are different temperature zones in home refrigerators, but that’s included in the general recommendation of 3-4 days for “prepared foods” category - which wet coffee grounds would fall into.

Freezer storage below-18 C is “unlimited” from a microbiological perspective - the activity of mold and bacteria is near zero. But over time, the quality of frozen food will suffer. Interestingly, it’s often the fats that still will go rancid, especially if the item isn’t wrapped tightly and oxygen can reach the product. Improper packaging and temperature fluctuations can also create freezer burn. As the oils in coffee are an important contributor to flavor, I wouldn’t exceed three months of freezer time, but that’s purely for quality reasons, not due to food safety concerns.

Our sister site Seasoned Advice has a generic Q/A on safe storage times and a lot of additional information.


What benefits does a Moccamaster offer compared to a generic coffee maker?

A Moccamaster is like any other electric drip brewer. It takes water and ground coffee and it brews a pot of coffee.

Is the difference noticeable between a Moccamaster and a generic cheap coffee maker and does it truly last longer?

From what I've read online, the Moccamaster is a decent brewer. As far as electric brewers go, I think that mostly refers to consistency. All the machine does is adding hot water to the grounds, so consistency means:

The water is added to the grounds at the same temperature regardless of the temperature of the cold water you're adding in the reservoir.

The water is dispersed somewhat equally over the coffee in the filter.

Based on the good reviews (and no personal experience) I'm sure that it will do the job as good as any other generic brewer. As for build quality, I think it's a decent design (premium materials even compared to the mostly plastic machines in lower price segments) that won't disappoint.
Looking at current retail prices though (about €200 in Europe or $300+ in the US), I can't help but mention that it's a steep price for adding hot water to grounds consistently.
Are there other machines which do a comparable job at a lower price? Definitely. The easiest way to find such a machine at a lower price is to look at a price comparison website for your own locale that includes customer reviews. Simply look for for drip brewers between $/€40-120 and sort them by rating. Then, to make sure that there are no hidden flaws (poor build quality, inconsistent brewing) you search for reviews of the candidate machine(s) online.
The reason I mention looking in your own locale is that some machines are priced reasonably well in one locale, but they're more expensive in another. I think the Moccamaster is a good example of that.
As an aside, I've seen some genuine recommendations for Moccamasters as well though in a slightly different context. The Moccamaster has been around since the sixties and it's produced by a Dutch company. As such, there are a lot of used machines out there and I've seen people recommend those used machines on Dutch coffee sites. Obviously, you wouldn't pay full retail price for a used machine.
At around $/€100, I think a used but good quality Moccamaster could be an alternative to a new brewer at that same price. For that price, you get a slightly sturdier build quality (copper coil for heating the water and a metal body). At the retail price, you are paying for the brand an the nostalgic factor as well.


Will Twist Press really taste like espresso, made by hand?

It depends exactly how much pressure can actually be applied.

To make proper espresso, you need 9 bars of pressure. To put that into perspective, that's about 131 lbs per square inch. I am guessing that there is no way the twist press can actually create that much pressure.

That being said, you will probably end up with something similar to what AeroPress or stovetop espresso (mokka) pot makes. Not quite espresso, not quite coffee. Its somewhere in the middle.

When dealing with espresso, its not so much about the time as it is the flow of the liquid through the puck. It's about a constant water flow at the proper temperature with a consistent pressure for the duration of the extraction. I don't think there is anything in press market that will ever be able to attain that.

Finally, espresso maker typically do not use paper filters, both the shower head and porta filter basket are metal.


Does a plumbed, self grinding coffee machine at 300-500 USD exist?

I had a friend requesting exactly this for his gym recently and we were unable to find a machine that fit all three constraints.

The options were basically choose a commercial level plumbed machine with a separate grinder, or a home level grinder / brewer combo and pour water in yourself.  I think there may be some basic technological problems with sticking a grinder right on top of a brewer, since it would probably be subjected to less than ideal environmental conditions (all that water vapor getting on your burrs / into the bulk beans can't be good)

If it is a low volume situation, the Cuisinart DGB 900BC might work, if high volume I would recommend a plumbed Bunn / Curtis Airpot system.


How much weight reduction occurs after roasting coffee beans?

The roasting process leads to water loss in all types of beans. Most beans start off at about 10-12% moisture and end up around 3%.
My experience gives about 15% weight loss (shrinkage) for light roasts and around 20% on dark roast profiles.

Example of a dark roast weight loss in my roasterie would be:
Starting weight: 240#
Roasted weight: 195#
Shrinkage = 195/240 = 81% of start weight so 19% loss.

I can't seem to find any online documentation of this. Just daily experience of being a professional roaster.


Consequences of wrongly cleaning espresso machine with vinegar?

I'll answer as a chemist and not as a coffee expert, but occasional exposure to vinegar won't substantially damage a piece of aluminum. Also ingesting traces of aluminum isn't toxic.


Is there a way to prevent acid reflux and gastritis while benefiting from cafeine?

One way which has worked for me -- but this of course depends on the severity of your condition -- is adding cream. Not milk but full fat coffee cream.

This dilutes your coffee a little bit, and suppresses any sour or overly bitter notes. Personally I like it even better than coffee without it because you get the softer coffee flavours that might usually be over powered in a standard coffee.

I would also ask why the caffeine is important to you? Regular consumption doesn't improve one's concentration as the body normalises to it.

However

I would consult your doctor and seek their advice. Acid reflux can be just a mild irritation and easily managed but it can lead to more complicated issues -- such as Barrett's oesophagus. If you are that sensitive to caffeine you might want to leave it alone, or, restrict yourself to decaffeinated drinks.

There is a good question, with answer, here on the subject of brewing coffee with a lower acid content. It seems cold brew coffee could be the way to go!


What variety of coffee berries are good for jam?

After much chatter about this question, I must admit that I've become a little obsessed with this concept. Maybe a lot obsessed...

Concept.  I see three other possible ways of making a jam/conserve/preserve/marmalade/jelly/... out of coffee fruit (i.e., coffee berries / coffee cherries) or coffee cherry husks (by "husks" I mean basically the fruit with seeds removed -- everything except the beans), in decreasing order of actual coffee fruit content:

Use the whole fruit (possibly with seeds and all), so as to make a conserve;
Make something like a jam or marmalade, using the shredded, dried, rehydrated husks;
Infuse the husks as cascara, discard the spent husks, then make a jelly out of the resulting brew (tisane).

Exclusions. Note that I am not including coffee jelly, which is made of (conventional, roasted) brewed coffee, as noted previously; also not including making a jam out of roasted or un-roasted coffee beans themselves. Both of those are interesting concepts, but discounted here to be left as separate topics.

Progress! I searched a bunch for a source of any coffee cherries or dried husks. Amazon didn't even seem to sell any (must have been my error!?). I asked around at a few local coffee shops, with little progress. I found a few pages, like this one and one from a NYT blog that gave a glimmer of hope that husks (at least) could be found. Both of those articles point to Counter Culture Coffee as selling these, but they're not in stock. An immensely helpful person from CCC pointed me to Verve Coffee Roasters, who sell coffee cherry husks for cascara. So as to get my lot before the rush on coffee cherry husks that would undoubtedly come from this post, I ordered some. Since I'm having trouble being patient and waiting for the stuff to arrive, I started...

Seeking Seasoned Advice! With all due credit to OP @EricPlaton, I posted a question over at Seasoned Advice about the concept of making jam or preserves out of coffee cherry husks or whole coffee cherries. I wrote a comment about this above, but I still hope OP doesn't mind!

More to come, and any comments or suggestions are kindly welcomed.


Could light transmittance be used to timely determine extraction?

Refractometers are widely used to measure the opaqueness of the coffee during brewing to timely determine the extraction time.

Spectrophotometers are used to measure color instead of opaqueness. They are mostly useful to determine the roast degree.

So, why not?

However, in my opinion, perfect is something defined by personal preference when considered with coffee.

If you want to find the perfect roast degree, you may choose your specific beans first, specific brewing method, etc. Then choose the specific roast degree. After that, a spectrophotometer may help you to find that exact point each time you repeat the roasting process. Similar to that, during brewing, a refractometer may help you to find that previously decided specific point each time you repeat that brewing process.

In summary, there is no guidance you can hear as the perfect point that you can scientifically lean on. But you may hear some advice based on the coffee community's common experience. Generally, if you are not into industrial production, you don't generally need nerdy equipment to follow such advise.


I wouldn't say that beans that have been roasted this much are sweeter. At some point, when the bean turns black the sugars break down into carbon and a brew with those beans would be less sweet than with a standard medium espresso roast. I guess somewhere at around the second crack the sugars will be gone and only "charcoal" is left.

So I'm assuming they either mixed the ground coffee with the sugar before you saw the coffee or you somehow missed it otherwise. Because a sweet cup with those black charcoaly things seems unlikely if you don't put sugar in it. As far as I know cuban coffee is indeed coffee with some kind of brown raw sugar mixed in it.


Of the various methods of decaffeinating coffee, which is the safest?

Swiss Water process is the best because it's the most natural and has the best percentage of decaffeination. However, none of the processes are dangerous, I repeat, none. Unless you consume the decaffeinating solvents somehow, that's a different case. -.-

Sourced from my previous answer at How is decaffeinated coffee made?


Chemically, what's happening to coffee after it's brewed?

The biggest chemical change that is going to occur is going to be oxidation.

Oxidation

Chemically, oxidation is defined as the following from this source.

  Oxidation is any reaction in which one or more electrons
  are moved from one chemical to another, producing two different
  compounds.

Specifically related to coffee, oxidation is further elaborated upon as:

  In coffee, the most common process is that an oxygen molecule donates
  two electrons to a compound, forming a new (differently perceived)
  compound and bonding with hydrogen to form water.

Oxidation of coffee occurs when oxygen molecules (present in the air in your flask and also dissolved in the water used to brew the coffee) come into contact with different compounds in the coffee. Even if you had no air whatsoever in the flask, this process would still happen due to the dissolved oxygen in the water used to make the coffee.

The process of oxidation occurs much more readily at higher heats, hence the reason why cold brewed coffee does not go stale as quickly.

When the oxygen combines with the hydrogen, water is created. That hydrogen ion, when it was free, was adding to the acidity of the coffee. Once it is no longer free and connected to the oxygen, in the form of water, the pH of the coffee will rise slightly, making the coffee more bitter. This is can be perceived as 'staleness'.

The compounds which are oxidized are the acids, aromatics, and oils.  All of these give your coffee it's great taste.

Loss of heat

As the coffee cools, the molecules will vibrate more slowly. This leads to a drop in temperature and will occur in any container, no matter how good it is. Since you have described a situation with minimal heat loss, this process is negligible.

In Conclusion

The oxidation causes the coffee to become stale. This is a bean roasters worst nightmare. For the brewed coffee, it dismantles aromatics, acids, and oils - all key contributors to the coffee's flavor. It also raises the pH to make it more bitter and adds water to the mix.

So no, it won't taste the same at 5 pm as it would poured first thing in the morning. The taste of the coffee will change over the course of the day.

Answering your final question about duration of freshness:

How long will your coffee stay fresh in a perfect flask? That is a matter of opinion. Every coffee shop has a different standard for how long they let their brewed coffee sit. It can be 15 minutes to an hour.

As soon as you roast a bean, it begins to stale. As soon as you grind coffee, it begins to stale. As soon as you brew coffee, it begins to stale. It's hard to qualify what you will consider to be 'fresh'. A purist will tell you that unless you consume the coffee immediately, your coffee will be stale.

As I said, it is a matter of opinion, and if you have the perfect flask, I would say you could wait about an hour before your coffee becomes stale. That's just me though. The sooner you drink it the better.

What You Can Do

Ensure there is little to no air left in your flask. You might also look into cold brewing.

If you want to read more about these chemical processes as they apply to coffee throughout the preparation process (roasting, grinding, brewing), then you can check out this resource.

Black Bear Coffee


When preparing a ristretto shot, should the brew time remain the same as a normale?

The time could absolutely stay the same for both your ristretto and normale shots. But - for that to happen your grind is certainly going to have to change, and obviously your yield (since you are now pulling a smaller / ristretto shot).

An example:
If you pull a shot that's:

20g in | 25s | 20g out

And then you decide to pull a larger/normale shot, but you want to keep the time constant. Then you are basically forced to loosen your grind to a coarser grind size.
Then you could pull your normale at:

20g in | 25s | 30g out

Hopefully that answers your question!


What is the optimal length of time for pulling a shot of espresso?

That will completely depend on the blend of espresso you are using.  Different coffees will have different pull times.

In my experience as a barista, you'll aim for about 28 seconds on most shots.  Some of the blends we've used aimed more at 25 to 31 seconds.

TL;DR: Depends on the coffee.


Why does the gas from degassing ground coffee smell bad?

My guess, based on what you've said, is that the two processes involved (that are giving you the off-smells) are oxidation and rancidification.

Rancidification ("going rancid") is a process by which fats (oils) break down into... other chemicals you don't want (and smell bad). The smell could be described as rank or rotten.

Oxidation is another class of chemical reaction that could also produce off-smells and tastes. This could be caused by contact with air (specifically, for example, oxygen) or other factors.

More broadly, autolysis describes other factors of, for example, plant material breaking down by itself over time (e.g., self-degredation by a cell's own enzymes). There are likely other factors like this, if you store coffee (especially pre-ground!) for any length of time.

These descriptions are admittedly non-technical. If you're looking for more, ping me in comments.

See also this question and its answers: When does coffee go off?  It discusses oxidation and other factors.


A quick Google search led me to this.
It's a very detailed site that explains everything you need.


How to order cappuccino without whipped cream in France?

You probably just hit upon a place that simply didn't know what a cappuccino was, or lacked the facilities to prepare one.

French coffee culture is a little different from Italian, but usually a cappuccino is much like what you'd expect.

I found this exhaustive guide to French coffee culture, and it notes:

  Capuccino – A French cappuccino is thirty per cent espresso coffee, fifty per cent milk, twenty per cent froth and no whipped cream. If the cafe you are in adds whipped cream then you must be in a cafe catering to tourists.

So it sounds like you just had bad luck!


Looking at the question from another angle, there’s nothing that would prevent an airlock, except your little pieces, of course.
The chance that the filter holder and the cup rim fit so perfectly for an instant lock is slim, but you shouldn’t underestimate the power to a bit of condensation when it comes to creating a seal. I had a similar problem just the other week when bottling hot syrup with a funnel without ridges: The first one or two were fine, after that, I got that splashing whenever the water film tore for a moment and ultimately had to lift the funnel ever so slightly over the bottle rim to ensure a steady flow. I have had issues with airlock when using a porcelain Melitta filter holder, so I can totally confirm that some types of filter holders do tend to seal.
Even one of your plastic pieces should already be enough to prevent the issue.


Certain Types of Coffee Machines Use Certain Filters?

Due to the fact that this is a lengthy question, I will try to be concise and to the point.

In short, yes, all of these main types coffee makers use a different type or size of filter. Sometimes each type can use a different filter. I will provide a non-exhaustive list of filter types for these coffee makers which you have listed. Although the list in non-exhaustive, it will provide the main types of filters for each device.

Understanding Permanent versus Paper filters

A permanent filter is often made out of metal and is, in most cases, a mesh (not true for espresso machines). They are not disposable and are made to be reused many times.

An impermanent filter is generally made out of paper and is disposable and is generally not meant to be reused.

Drip Coffee

Drip Coffee machines are one of the most common coffee machines for home use. The filter used will either be paper or permanent.

A paper filter for the drip coffee machine will either be flat-bottom or cone-shaped depending on the make and model of the coffee machine.

Flat-bottom filters:

Cone shaped filter:

The permanent filter can take the same shapes, however it is generally a flat-bottom shape yet can be a hybrid between a cone shaped and a flat-bottom shaped filter. I can only describe this as an upside down triangular prism. Below is a picture of the aforementioned hybrid filter.

Single Cup

These filters are generally made out of paper and are usually a cone shape which is usually specific/unique to the type of single cup brewing device.

French (Push) Press

A french or push uses a permanent filter which is made out of a fine metal mesh. It is on the bottom of the plunger. The entire bottom of the filter has three main parts, shown below.

The Parts of a French Press Filter:

Espresso Machine

An espresso machine's filter is called a portafilter. It shaped like a small basket, made out of metal, and has small holes in the metal on the bottom. There are three sizes. The most common are the single and double shot filters and a rarer one is the triple shot filter. They increase in size to hold more ground coffee.

There are generally three types of portafilters in circulation with mainstream home espresso machines.

Single wall. This is the most common in the industrial setting. It is contains only one wall on the bottom of the filter.
Double wall. Think about this as a portafilter for the inexperienced and is most common for the home espresso machine. It has a secondary wall on the bottom of the portafilter with only a few holes in it. The presence of two walls helps to regulate extraction pressure and is therefore good for those who are not very good at tamping pressure and grind size.
Pod filter. This is simply a specially designed filter that is the same shape as the others and comes with some home espresso machines. They are used to hold pre-made and pre-packaged espresso pods that one simply drops into the filter and can avoid many of the other steps of traditional espresso brewing such as tamping and grinding.

Portafilters (single wall) on left and baskets (which hold them and are upside down) on the right:

The filter on the left is a single shot and the filter on the right is a double shot.


What is the process to reduce bitterness in coffee?

There are a lot of factors that contribute to the bitterness of coffee. Some of these have to do with the concentration of various compounds in the coffee and the roasting process, but the way you brew the coffee can make a big difference as well.

Assuming that you are not going to be harvesting and roasting your own coffee, we can focus on the brewing process.

Buying Beans: Robusta vs Arabica

To decrease perceived bitterness in coffee, the best choice is Arabica. Arabica beans are often sweeter with notes of sugars and fruits and a somewhat wine-like acidity. Robusta on the other hand tends to be harsher with more bitterness. This difference in quality is reflected in cost however, as Arabica tends to be more expensive than Robusta.

In terms of roast level, medium roasts generally contain fewer soluble solids, more acidity and a stronger aroma than dark roasts. All of these should contribute to making medium roasts on average less bitter than dark roasts.

Water: Temperature and Chemistry

You have to find the sweet spot when it comes to temperature, a little trial and error can be used here depending on the blend and brewing method. For example, the people at AeroPress recommend a much lower temperature to reduce bitterness that what you would use in a french press.

In general research has shown that coffee brewed in hot water is perceived to be less bitter than when cold water is used. Additionally, bitterness is reduced when hard or soft water is used when compared to distilled water.

Brewing [Extraction]

Bitterness is strongly correlated with the amount of dissolved solids in the brewed coffee. To ensure that the amount of dissolved solids and the overall extraction is correct (and minimally bitter), make sure to use the correct grind coarseness, water temperature, and brew time for your chosen method. Over extraction can be a major cause of bitterness.

Drip and pour-over brewing methods tend to have less bitterness than a french press or other immersion methods. This can be attributed to less dissolved solids in the coffee.

SCIENCE

Much of this section will be outside the control of most, but it is interesting nonetheless.

Research has found that the introduction of polyphenols reduces the bitterness of coffee. The metallic bitterness found in some coffee has been attributed to  dicaffeoylquinic acids. Trigonelline is perceived as bitter at concentrations of 0.25% and its degredation is proportional to roast level. Roasting Trigonelline produces a byproduct called pyridines and helps create the roasty aroma found in some coffee.

Chlorogenic acid is also found in coffee, higher concentrations in Robusta than Arabica, and that contributes to the bitterness as well. Additionally, Quinic acid is a product formed from the degradation of Chlorogenic acid and is present in coffee at twenty times its taste threshold, contributing to the bitterness.

Furfuryl alcohol is also known to increase the bitterness of coffee.

More Information

Coffee Chemistry: Cause of Bitter Coffee

Coffee Basics: The Difference Between Arabica and Robusta


Is it hard to clean an Automated Expresso Machine?

The clear answer: It depends.

First, not all fully automatic models are constructed in the same way. Which also means the required effort varies between brands and models. Some are pretty self-cleaning, others less so. Checking consumer reviews on the usual shopping websites should give you a first idea.

Second, regular cleanup is non-negotiable. If you skip daily cleaning, your machine will become a breeding ground for mold and bacteria. If you doubt that, simply open the machine in an average office where everyone pulls a shot, but nobody bothers to do more than dump out the used grounds every now and then. Especially the brewing part and various pipes can turn you into a tea drinker at a glance.

Of course a two- or three-part setup of grinder, espresso machine and maybe frother must also be cleaned, but apart from the parts touching the milk, you deep-clean far less often (e.g. dismantling the grinder) or a quick rinse or wipe will suffice.

So you have to find your personal threshold for the covenience vs. effort question. The answer will depend on the machine model, but also on the kind of use the machine gets. For our household where we pull between (usually) two and (rarely) eight shots a day and only occasionally steam milk, we purposely picked separate items, but that was also based on counter space and kitchen layout and the charm and flexibility of “handmade” coffee1. My parents decided that for about the same parameters an all-in-one machine was the best choice.

————

1 We used to quite happily work with a Mokka before buying an espresso machine.


Why do some coffee beans produce more dust than others when ground?

(1) Burr grinders are known for more precision and consistency than blade grinders.
(I haven't tried a blade grinder, but Specialty Coffee says

Now, once the grinder is loaded, don't just hold the button down and let it rip... use short bursts of a few seconds each so the coffee doesn't overheat.
Make sure you have a hold on the top of the unit and give it a shake during bursts so that the grounds get well mixed while grinding. This will make the grind much smoother and consistent.

Be careful that some "burr grinders" have blades and burrs.)
(2) Cold beans grind more consistently. Per NY Times:

But to achieve consistent flavor you may just need to chill your beans before grinding them. Colder beans produce smaller, more consistently sized particles when ground, yielding more flavor from less coffee, according to a study published in Scientific Reports.
As room temperatures vary and grinders heat up with use, the consistency of the resulting grind changes. That’s a problem, because water extracts flavor from smaller coffee grounds faster than bigger ones. An inconsistent grind means sour taste from the small grains, and a bitter one from the big, all at the same time.

(But I'm pretty sure that last sentence is reversed.)
Note that some grinders heat up with use.
(3) Different bean types, roasts, and ages might produce more dust than others when ground, but I don't have good info on that.


Should any coffee be extracted during pre-infusion?

As I said in a comment, I'll lay out a few factors that you need to experiment with.

  If I put the grind size very fine (a 3 or 4 on the dial) I'll get less during pre-infusion, but even less during the real extraction and also it'll be sour or whatever; you can't taste the flavour of the coffee. This happens both with the single filter and double filter.

So this is the first factor: grind size. You can probably still tweak it a bit and you'll want to do so with the smallest step the machine allows. I don't know how many steps your machine has (my Oracle goes from 0 to 45, I think) and it allows a decent adjustment in grind size. It's not as good as a dedicated high-end espresso grinder, but it helps to to tune in the right direction pretty well.

If you're not extracting enough then you're grinding too fine or tamping too hard. So that's why I commented about tamping which is the second factor. Those two are related, if you grind super find but tamp it only very lightly then you'll still get a full extraction. The trick is to find a balance between the two and that can change from one bean to another. So instead of taming harder on the coarser grind, you can also try a finer grind with a gentler tamp.

  Surprisingly the descale light has never come on, so I've never descaled it. I'm trying to keep the grounds even and I use the razor to even out the ground at the end (I blow out excess grounds dug up by the razor).

This is yet another factor. The razor is probably good for reproducibility, assuming it doesn't ruin what remains in the filter. On the other hand, you might benefit from a bit more coffee in the basket, especially when you're using a slightly coarser grind. So this is also a factor to experiment with.

Finally, there's the extraction time. While it's often advised to have about 30 seconds of extraction time, it's certainly not set in stone. Too long and you may get a bitter cup and too short probably won't get enough volume in the cup (or not enough pressure) but it's something to try.

For example, I've had ristrettos taking 40 to 45 seconds on a 1:1 ratio with a fine grind that were nice and sweet. Indeed, had I stopped those shots at 20 to 25 seconds then they would've been sour similar to your description of the very fine grind.

  I would use a finer setting for the grounds, but my pressure after pre-inf is already very high. Like how is water flowing through the portafilter equally fast with and without pressure? I don't understand the physics of it.

In reply to this comment, it depends on how your machine does pre-infusion. For example, the Oracle builds pressure normally but it has a relieve valve that you can set at a percentage of the normal / maximum pressure. The minimum for my setting is 55%, so it certainly builds some pressure during pre-infusion.

As for the flow rate, it probably isn't flowing as much at the lower pressure. You could obviously compare the time and even compare with an empty basket, that'll flow a lot faster (at least on my machine it does).

  I've had the machine for 6 months. Surprisingly the descale light has never come on, so I've never descaled it.

It's probably a good idea to descale regularly anyway. It depends on the hardness of your water, and it's probably not the culprit here, but I'd try to make it a habit to do at regular intervals (monthly, or bimonthly depending on water quality).


First of all, there is no difference in the beans themselves. They all come from either Robusta or Arabica plants. The roast doesn't vary either. You can use any kind of roast for your espresso, it's up to preference.

What does change is the grind. Espresso grind is very fine - much finer than other preparations of coffee.

You may find packaged coffee sold as 'espresso beans' or 'espresso roast' being darker/bolder roasts, to emulate a darker, stronger coffee regardless of preparation, however it has little to do with real espresso (and you may even find 'espresso' ground coffees being sold with a large/inconsistent grind!).


If I were you I'd go with the baratza encore (or something similar). It will do just fine for a pressurised basket and it's great for filter too (if James Hoffman uses it for his filter it's good enough for you and me). Don't buy a blade grinder, I've made that mistake. You will taste a huge difference between the two, the blade grinder being bitter and yucky. It's all about particle distribution and a blade grinder does the worst possible job at that.

So, spend the money for a decent burr grinder and you won't only have better espresso; you can make delicious filter coffee too!


is it true that some coffee types contain elephants dung?

This is actually called black ivory coffee.

Cambodia is not actually where you get this coffee originally. The company that creates this coffee is actually based in Thailand and uses coffee beans and elephants in Thailand to make this weird sounding coffee. As said by Wikipedia:

  Black Ivory Coffee is a brand of coffee produced by the Black Ivory Coffee Company Ltd in northern Thailand from Arabica coffee beans consumed by elephants and collected from their waste

A simple Google search brings up a lot of results on black ivory coffee where your Telegraph article comes up as the first result. Thus, this does exist and is not a hoax.


This looks like oxidation, try cleaning it with hot water (NO soap). After most of it has gone, fill up with hot water again and add a few spoons of bicarbonate. Stir and let it sit for a day or 2. After that, rinse and inspect. If the oxidation has gone too deep, the pot will need sanding and polishing, which will weaken the pot. In that case it would be better to ditch it and get a new one.


Why some coffee pods are under pressure?

Inert gases are known to be chemically stable; they don't react with materials around. Based on that fact Ernesto Illy, the son of the founder of the famous coffee roasting company, invented the method of filling a can of roasted coffee beans with pressurized inert gases. Many years they held the patent for this method and still pressurized roasted coffee cans are the fingerprint for that company. This method is known to protect the roasted beans for a longer period; however it's not magical. So, the beans will stale eventually.


Can the MahlKoenig EK43 be calibrated coarser?

Yes you can adjust the calibration of grind size of the EK43.

Have the grinder plugged in and ready. Turn the adjustment knob all the way to the right. Losen the two screws on the sides of the knob slightly (turn the hexagon shaped screwdriver once). The screws are on the sides of the knob, fixing the big adjustment screw in the middle of the knob. Once they are losend you can use a flat head screwdriver or a coin to turn the screw in the middle of the know. Keep the knob totally turned to the right, to the smallest grind size setting.

So now normally you would turn it slowly to the right while your grinder is turned on until you hear a slight rattling sound. This sound occurs when the burrs are touching. Once you hear the sound, immediately turn the screw back by about ten degrees until the sound stops and the burrs aren't touching anymore. That is the standard calibration and the only one viable for espresso.

In your case you want to turn the screw further counter clockwise, so the burrs are further apart until you get the desired grind size. The maximum grind size will be coarser as well as the minimum. That also means that the grinder will not grind fine enough for espresso anymore.

I don't know if this is recommendable to do, I don't think anything can break. But I will also not guarantee it. To be sure write a mail to Mahlkönig. Also I think there are instructions in the grinder manual on how to calibrate it (to the standard espresso setting).


There's no strain of coffee bean that has no caffeine when it is grown, but you can find whole-bean, decaffeinated coffee. "Decaffeinated" coffee has been treated to have most of the caffeine removed. Decaffeination is done when the beans are still whole, so you can certainly find whole-bean, decaffeinated coffee (though I suppose decaffeination could also be done after grinding). The decaffeination process is often done with whole, green (not-yet-roasted) beans, which are subsequently roasted (still whole). Most places will sell whole-bean, decaf coffee -- local coffee roasters, coffee shops, markets, mail order from the usual suspects... Starbucks, illy, Lavazza, Peets, ... Look for "whole bean decaf".

For more on the subject of decaf coffee, see this question about how decaf coffee beans are produced and another question about the fact that decaf coffee still has a little caffeine in it.

The concept of "half-caf" coffee has become popular, mixing part decaffeinated beans with part regular (not-decaffeinated) beans, which might be a good option in your case to reduce (but not eliminate) the caffeine. These half-and-half blends are also available from retailers.


How should I get the most flavors from my coffee in different temperatures while drinking?

Interesting question.
You are not alone when noticing flavor differences with different temperatures of coffee. When cupping coffee in a controlled lab situation for Quality Control purposes, I will often make multiple passes through the cups to taste the differences that are present as the coffee cools. Doing this tells me/us what we need to do while roasting to highlight/change the flavor profile of the roast.

The high acidity/brightness of a light roasted Kenya disappears as the cup cools. The darker roasted coffee that will show more "sweetness" at a high temp will show off more as it cools. These are but two examples. Other flavor characteristics that are found in roasted will definitely change as the coffee changes temp.

A lot of what you are tasting is perception. Here is a link to the key being how our taste buds translate it to our brain.

Food temperature affects taste, reveal scientists

Once the coffee is roasted the only thing you can do to change the flavor profile of your coffee at high temperatures is changing the brewing method. All the variables in brewing will without a doubt change the flavors that you perceive.
This will lead you to experimentation to find the flavors that you want to see.

Understanding Body vs Flavor Clarity

Hope this helps..


Where should I look for food-grade nitrogen fills?

I talked to homebrewing supply stores looking for "Guinness mix" or "beer gas" pre-filled bottles for sale. While this isn't a pure 100% mix, it's about 75/25 or 70/30 and usually means the supplier mixed it for them. After a lot of digging at homebrew suppliers, I found that one of their suppliers does smaller batch orders, which can be difficult since fequently breweries sign up for a delivery schedule with large gas suppliers.

The gas supplier is an industrial welding and gas supply store -- don't let "industrial" in the name dissuade you from calling and asking about food/medical grade. This industrial supplier also has food grade tank exchange.


Is there any way to preserve roasted coffee beans?

Coffee beans, once roasted, are perishable; they don't "keep". Within roughly five days of roasting staleness is detectable (taste/quality is adversely affected). There is one way to preserve freshness: consume freshly roasted beans within roughly a week. Don't freeze; beans absorb moisture and lose flavour— ick. Vacuum packs aren't the answer, either. To remove all gases from packaging would require a system using pressure, 29" Hg, that no one, not even coffee giants, can afford. The best practice is to just buy beans (roasted on the day you purchase, ideally) in quantities you'll use within a week to 10 days.


Is it good to have the "floating oil" on the surface of some coffee drinks?

Nice question. A similar myth has been arisen for Turkish coffee pot; such as it should be cleaned only with water to keep the greasy surface made with coffee oil.

Partly correct, partly not. According to my "Barista's manual" from Lavazza, this sedimented oil may acetify. Thus, end up bad flavor.

Again, (I cannot remember the source) as of my knowledge, paper filters are very good filtering everything; including those valuable oils. (That's why classical French press is still very common to prepare filter coffee, I think.) Paper soak in most of the flavor itself if it does not have proper fibers. This seems like the main problem of any drip coffee machine, V60, Chemex, etc.

Final words: keep it clean in the long run. You may not necessarily clean it until acetifying; which is you may keep it as it is up to one-two days.

Same rule for Turkish coffee pots. :)


Does brewing a larger pot of coffee change the taste, even if you keep the ratios the same?

The extraction time will be longer for the larger pot, changing the taste, not necessarily for the better.


Is it Okay to Reuse One-time Coffee Filter Cups for Coffee Pods?

If you can remove the coffee grounds/filter and replace just those, then yes it will be safe from a health perspective.  The plastic in the filter "cone" should be food safe, though durability may be an eventual concern.  The plastic cup base can definitely be reused, as is intended.

As far as the practicality concerns go, it may be more of a pain than it's worth.  The coffee containing part of the filter funnel is going to be pretty well attached, in order to keep it from slipping into the cup below and steeping (like tea) vs. simply having the water run through it.  You could probably remove the coffee filter and perch a coffee pod in it's place, but it would not be sealed to the plastic cone, and hot water may run around it without actually percolating through the coffee grounds in the pod.


What do you mean by improve? French press is one of the most popular brewing methods in the world, and rightly so: it's dead easy to operate and produces a great cup of coffee. The mechanism is very simple and easy to clean, a good french-press pot will last years if not decades, and if any part of it breaks it's cheap and easy to replace.

What improvements might you make in general? Control over the brew is probably the most important, and with French press is there really anything you could add? The plunger separates the grounds and the coffee very effectively in a good pot, so not much room for innovation there. The other main variables: grind and timing are beyond the scope of the actual pot. In terms of maintenance and ease of use, the pot is optimal already too.

One could argue that the Aeropress is an improved French press, since the brewing method is similar, especially if you use a metal filter. But it's more of a faff to use, doesn't scale so well (you can get 12-cup Cafetières), and tailored much more to the coffee enthusiast than the average person who just wants a cup of what the know and like.

TL;DR A cafetière is already optimal for making French press, there's no room for significant innovation, beyond inventing new ways to brew coffee.


What coffee and roast are best for tiramisu?

From a cooks perspective, I think it should be "espresso", or "caffè" not "coffee" in any good tiramisu recipe, which in turn would already suggest a type of beans and roast.

Note that the Italian term caffè denotes the strong black liquid you get from an esspesso machine or a moka.

The coffee in a tiramisu has to be concentrated to supply enough flavour without soaking the ladyfingers or other bisquits used. (The same principle applies when you use a liquor.)

When choosing the beans /the roast, the same rule as for wine applies: Use what you drink. And seriously, unless you are making an insane amount of tiramisu, you will be using only very little of one pack of coffee.
I use whatever I choose for my Espresso (if I feel rich, I'll splurge on something from my local roaster, in a pinch the usual suspects like Illy or Lavazza, sometimes even a Starbucks Espresso roast cough) and call it a day.

So in sort, get a classic Italian espresso roast, prepare it authentically and you should be fine. In a pinch, use another coffee, but make sure it is very strong. You'll need a few tablespoons tops for a standard tiramisu recipe.


Safety concern regarding aluminum foil inside a moka pot

With the moka pot being made of aluminum itself, there isn't really any health effects from using foil. If there is a worry about ingesting tiny flakes of aluminum, you'd a worse time eating that leftover lasagna.
The only caveat is if you use too much and it wedges the funnel into the basin and you can't remove it. As a side note, with the pot being much thicker than the funnel, it would also be pretty much impossible to crack it doing this.
If you have followed his advice and made sure the gasket is in good shape and not indented too much. The lip around the funnel could be out of shape, and like he showed sits deeper than what the gasket can seal.


Three quick and easy hacks you can do without throwing capitol at the issue:

Shoot a dud pot first thing in the morning.  By brewing a coffeeless pot and throwing away the water, you will empty the the Bunn's hot bladder.  Think of it as a morning tinkle for the CWTF15-APS to git rid of the rank overnight water fouling your morning joe.
Use an extra filter. Substandard inputs are signiflatulanceficantly improved by an additional filter.
Scrape the the cheeto and donut leavin's off of the lip of your coffee cup once in a while.  The "seasoned" coffee cup is a myth as proven in a blind taste test where we forced coworkers to drink coffee from a randomly selected sampling of well seasoned and clean coffee mugs.  There was a little bit of a flatulence effect with seasoned mugs in that a subset of coworkers "liked their own brand" in testing, but the overwhelming data suggest that dirty mugs are just gross.


How quickly does ground coffee get stale?

I can say, by experience, that it's not a superstition. Maybe not seconds, but for sure it's just a few minutes.

Maybe someone could find a reference to an experiment or I may encounter and add it later. But, you can easily observe it by your nose.

The aromatic components are the source of the flavor in coffee beans. When you ground them, you crack them fine. The components get free and start to evaporate. That's why you can smell them. However, we want to taste them so badly. So, we need to trap then into the water as quick as possible, before most of them evaporate.

Below is a nice chart that shows how quickly coffee goes stale when it's stored as whole beans. Ground coffee, I assume, would be similar, but so much quicker as the surface area is greater for evaporation this time.

When does coffee go off?


Can a handheld milk frother produce micro-foam?

It certainly won't compare to a steam wand, but yes you can totally get okay milk texture using one. In all honesty though, I've had better success using a french press. Heat milk via stove stop, put your milk into a clean french press, and push and pull the plunge repeatedly until your milk froths. It's not perfect - but good enough to pour some latte art.


My opinion is that you can use citric acid. That's all that I use and I use it with my espresso machines, drip coffer maker, and I have used with Nespresso and Keurig machines. It is food safe. I buy it at my local beer and wine supply store. I have read to to use 12 - 18 grams of citric acid to a liter of water. I believe many descale solutions are made from citric acid. I use 3 1/2 teaspoons of citric acid to 40 oz of water to make my descaling solution. You can follow the manufacturers suggested routine of descaling.


I actually might say no.

This type of coffee is rather expensive at $100 to $600 per US pound. Yes, 100 to 600 USD. This is natural Kopi Luwak coffee at a normal price. The word blend sounds a little fishy to me, as it usually means that it is not entirely pure Kopi Luwak.

The thing is, it's really up to you to decide for yourself. If you can trust them, buy it. If you think the product isn't what you want, don't buy it. I will probably say no, but you make the final decision. Go with your gut and say yes or no to buying that product. Good luck!


How do I keep slime from collecting in my drip tray?

If what you're seeing is mold or algae you may want to add a few table spoons of salt to the drip pan.

I'm guessing that your slime is probably a fungus of some kind, rather than an algae. It has found a rather nice living arrangement for a fungi. Plenty of warm water and decomposing coffee, with very little light.

Salt should in most cases prevent fungal growth, this may sound odd but it will dehydrate the cells even when they're immersed in water, sort of a "water, water everywhere but not a drop to drink".

If you would rather get high tech with it, you could try a UV light, similar to the ones used in AC systems. The harsh UV rays will kill most molds and prevent them from colonizing.


What is the cheapest way to use coffee beans?

There are many ways to brew coffee, and several that are on the "inexpensive" end of the spectrum. Your tone sounds like you're not very into coffee, so to that end here are my broad recommendations in that will give you an adequate cup with minimal fuss and expense.

You'll need two basic pieces of equipment:

A grinder. You can buy an inexpensive electric rotary grinder that will be adequate for most purposes -- one example from Amazon. You can also use it for grinding spices or seeds. If you already have one, you will get some odor holdover from one grinding mission to the next, but it's probably fine if you're not very picky. 10-15 quid new, or even cheaper used from a thrift shop etc. You can even mash them up with mortar and pestle.

Some brewing mechanism. The cheapest and simplest are probably drip brew (e.g., pour-over or auto-drip), but I online a few more down below. Your options are manual pour-over (my recommendation) or auto-drip:

Manual pour-over. My pick would be a manual pour-over coffee cone, such as this one, a plastic cone holder for like 5 quid. You put the cone over a mug, put in a paper filter, add medium-grind coffee (even as fine as the rotary grinder will give you will be okay), and slowly pour water over the top until brewed.
Auto-drip. You can find a really cheap auto-drip machine, for instance this one from Amazon, for like 10-15 quid, or even cheaper used. Water goes in the reservoir, paper filter in the basket, add some ground coffee, press the button.

That's one solution for decent cup of coffee for as little as 15 quid all in (grinder, coffee cone, paper filters), or perhaps 25-30 for an auto-drip solution.

See also questions tagged as pour-over for how-to information.

Other inexpensive, though somewhat more fussy, preparations include...

French press and french-press
stove-top percolator or moka pot, see also my description of the difference between them and moka
cold brew; see cold-brew.


Unfortunately I can give you only a half-answer.

A) No, I can’t explain what caused the hole. It looks somewhat corroded and I wonder where the discoloration comes from - maybe worth checking the cause of that and the composition of your water?

B) I discourage repairing the hole in general. For two reasons:

You’re operating the pot under pressure. Any repairs have to hold up to that and not just “hold the water in”.
Soldering and food safety are a tricky pair. You have to ensure that nothing can leach into the water that shouldn’t be there.

In short, you will need either experience beyond some household tinkering (which I kind of suspect you don’t have, because then you’d probably have patched it up already instead of asking here) or have to pay a professional - which considering the price of a new pot probably isn’t economical. (If this pot has a special emotional meaning, other considerations come into play, of course.)

But whatever you do, I encourage you to do some more digging into probable causes before you end up with another hole in the new pot.


What kind of Foam goes best with types of coffee?

It's just a matter of tradition, style and skill. Traditionally the thick, hard foam with bigger bubbles is used in Italy for Cappuccini. Same goes for espresso macchiato. Sometimes the milk foam is spooned on top of the espresso. In other countries they often imitated italian style coffee, which is why e.g. in Germany the foam is usually very thick as well. In Australia they developed italian coffee culture further and usually froth more silky (and make flat whites with it).

When it comes to skill, it is much harder to produce silky foam than the "traditional" foam. You have to start with cold milk, then introduce air at first, but also not too much and lastly spin the milk/foam mixture to break up big bubbles and to work the froth into the milk. In order to do all that you have to get the depth of the spout in the milk right, you have to get the angles right and you have to be careful not to heat the milk too much, because otherwise the foam will become too thick and hard (and the milk will get bitter). For the thicker foam you can basically just put the pitcher under the steam wand, let it sit for a while and come back. Not gonna be pretty what you fine there, but it works.

Third wave and specialty coffee shops usually froth the milk to a silky texture, so called micro foam. That's a different style and there several reasons for it why it is done that way. The most important one is that the taste is superior. Frothed milk above 70 degrees starts tasting bitter. Most specialty coffee barista probably froth the milk to somewhere between 62 and 64 degrees. That way you get a sweet taste and micro-foam. For the thicker foam you would need higher temperatures and thus destroy the taste of the milk.


Raw green coffee has a shelf life of about one year. Roasted beans last from a few days up to a year depending on how packaged; ground coffee even less than that. (source)
Based on that, the probability of B is practically zero, so I wouldn't risk finding out about A! (Seriously though, if the beans are at all mouldy, don't use them.)


Cold brewing at varying temperatures - How does steeping temperature affect extraction?

Okay, so what if I told you, that I sell a lot of cold brew at my shop, and have had success with 4-hour steeps.

I've tried a bunch of stuff, and I've realized that since the temp is really low (mild to cold), it barely makes a difference in TASTE. The biggest factor is oversteeping (like, 48hours up brew), as it can make your cold brew sour. But as a rule of thumb and for sanity of the production team, I go for cold water and steep for 8-15 hours, depending on the time of day it's made.


Coffee and milk for the lactose intolerant

Best option is lactose-free milk. I assume you live in India and it may be hard to find in India as lactose intolerance is not common among Indians. In that case, you may try goat milk which has naturally less lactose than cow milk. But I'm not sure if this will be enough (personally) for you.


Is the recall of Solimo coffee capsules a serious issue?

I did a quick search and didn't find anything either.  If it was very serious there would articles about it all over the place. It would be a natural clickbait for the newspapers. "Coffee Recall - Read All About It"

If it is as described then it sounds benign from a health perspective and the notice is the company covering itself from legal action.


Coffee cup patina; is there any logic in not washing the cup

It may be superstition but many people, myself included, don't wash out their coffee cups. I rinse out my cup but don't wash it - I don't want soap going into my favorite coffee cup. I like the way it smells of coffee. I don't have to see or touch my favorite coffee or tea cup to know which one is which.

In addition I never use soap on either my coffee or tea filters.

Would I notice the difference if I had two identical mugs - one with the "patina" and one without? Maybe not. But I prefer it that way.


Don't think you can replace only the gears, but I found lots of places selling replacement lids with heavy duty gears.  Check the link out below:

WhirleyPopShop

I googled 'metal gears for whirley pop' and got a ton of options.  By the way, it appears that the gearing on the lid in the link above is held together by allen wrench tap screws so you 'might' be able to scavenge the gears off the lid and put them on your own, although, if the lid itself works well, then I don't see why you would want to do that.


WebMD does list some negative side-effects when taking cardamom.  Looks like cardamom has health benefits too.

But I have a suggestion (gleaned from the back of my jar of cardamom pods). Instead of using a spoonful of ground cardamom, consider getting cardamom pods, squeezing 2 or 3 of them to crack them a little bit and placing those in your coffee cup.  It definitely augments the taste of the coffee in the positive direction, plus you're not eating ground cardamom.


How much time should I wait between drinking coffee?

I don't know that this is a standard time period.. Honestly, the more coffee you drink, the less you are going to get the 'buzz' going. A lot of this depends on your body type, activity level, and genes.

You have to think of caffeine like a drug, because that is what it essentially is.  When you take your first sip of coffee, it takes about 45 minutes for 99% of the caffeine to be absorbed by your system.  The caffeine has a half life of roughly 4-6 hours in the human body.  That buzz you are feeling is because as you have slept, all of the caffeine in your system has been depleted and thus when you get that first cup in the morning, your system gets a big blast of caffeine after not having any.

Here's a pretty interesting article that contains a lot of the information I just parroted above (plus quite a bit more):

Caffeine Metabolism


Is it normal for coffee beans branded "Seattle Mountain" to shine?

To start, I would highly doubt the beans were roasted there in store.  Roasting at a commercial level takes large specialized equipment that would be dangerous for average customers to be around (400F+ after all) and create a smell that would easily fill the entire store and be unpleasant to some customers.

That being said, unless there is a roasting date on the bag, there isn't really a way to tell exactly when the beans were roasted.

The oils on the outside of a bean can mean many things.  Any given bean will generally become more oily and shinier as it is roasted darker and the oils migrate to the outside of the bean.  This is a process that happens near instantaneously with the roasting process.  However, it also continues much more slowly after the roasting process and beans that have been improperly stored or become stale may become more oily than they were immediately after roasting.  However, some processing methods will also produce beans that become more oily earlier in the roast process.  Dry processed coffee will often start to oil at a much lower roast level that coffee processed by current wet methods.

The oil does not make the process less efficient by any noticeable measure.  Some of the oil is transferred to the paper filter and some ends up in a cup.  Many people claim to prefer metal mesh filters because more of the oil (and flavor) ends up in the cup.  However, other people claim they can't tell the difference.  The oiliness CAN affect the grinding process if the grinding machine is gravity fed and the beans cling to each other or the container too much.

TL;DR The oil level or sheen of the coffee can't tell you much unless you know other things about the coffee as well.  It doesn't effect the brew process very much either.


How many grams of coffee to use with the George Howell Kalita Wave recipe?

The given ratio is maybe a bit unusual - many sources for pour-over irrespective of the exact brand (Chemex, Hario,...) give 1:17 or 60g per liter of water, which is 16.666. This seems to be the ballpark number for pour-over.

But is the Kalita different?
Your source calculates between 1:13.9 to 1:15.6. Interestingly, at least one source (in German, sorry) agrees with the ratio of 1:15.4 for the Kalita, yet another goes as low as 17.8.

  Conclusion, sort of:
  The ratio is opinion-based and a matter of taste.

Of course it’s up to you to go significantly lower - you won’t be breaking any laws - and I will freely admit that I am a total whimp when it comes to coffee strength.


Finding if coffee is a health risk after best before

With all foods, FAT TOM is your best start to gauge their susceptibility to spoilage.

Now, FAT TOM is actually an acronym for the six factors that influence the growth of microbes. And bacterial growth is what causes food to turn bad in two senses, namely gross and dangerous, although the two often go hand in hand.

The factors are:
Food
Acidity
Time
Temperature
Oxygen
Moisture

In theory it's sufficient to eliminate just one factor to prevent spoilage, but in practical applications, it's often a combination of a few.

So for your coffee, the main factors are moisture, food and time.

For your Nescafé, the granules are dry, have very little "food" for pathogens (proteins are a real problem, for example) and are around or slightly past the best-before date1. If you say the coffe still tastes fine, I see no reason to suspect it to be unsafe.

I'm not sure about the second product, but will for now assume it's some kind of "cappuchino mix" that includes dry milk or another kind of creamer. My conclusion is largely the same as for the Nescafé product, but with a higher protein ("food") and possibly fat content. So you have a slightly higher risk of "spoilage", but it's not really about food safety, just rancidity and development of "off" flavours.

So to sum it up:
If your instant coffee still tastes fine, dissolves as it should and was stored in reasonable conditions (dry, room temperature, closed container), there are no food safety concerns. You might want to use it within the next few months, though, but mainly due to quality reasons.

1 Another common misconception: "best before" does not indicate immediate spoilage after that date, it is a time by which the manufacturer assures you the product will be in excellent condition. This means also sensory attributes like taste or consistency. Plus there is always a safety margin included to be on the safe side, even if the consumer stores the product under less-than-ideal conditions. More on our sister site Seasoned Advice, for example here.


What does the 'strength' mean (in numbers)?

Coming from Germany myself I have seen this rating only on a single brand of coffee. There is no standard for this (even though us Germans seem to like standardizations), but basically strength of the coffee is about the inherent bitterness and caffeine content you get out of it.

The stonger a coffee the more caffeine and also the more bitterness you will usually get.


What makes coffee from a coffee shop/cafe better than the coffee I make at home?

Three things contribute to a good cup of coffee.

The coffee itself.
The tools used to prepare the coffee.
The skills of the person making the coffee.

Unless you're talking about espresso or espresso based drinks (cappuccino) the skill involved is easily developed.

Do you use a burr grinder or a blade to grind your coffee? Or do you use pre-ground coffee? This, believe it or not, makes a huge difference. Coffee shops use a burr grinder to get a consistent grind.

Without knowing the coffee shops you're referring to (as well as your own brewing habits) it's hard to give a reasoned answer. It may simply be the coffee used and the amount of coffee used.


How does coffee grind size affect coffee taste

The main reason for different grinds is the different brewing processes. If the water is exposed to the grounds for a very short amount of time (e.g., 10-15 seconds for espresso), you need a finer grind to provide enough surface area to extract the coffee from the beans. If the brewing time is long (e.g., the ~4 minutes of french press), you need a coarse grind to avoid over-extracting the grounds and getting something too bitter to drink.

That's really the heart of it. If the grind is too coarse for your brewing method, your coffee will end up under-extracted, weak, and acidic. If it is too fine a grind, your coffee ends up over-extracted and bitter. Your grinder is a good brand; if you still have the manual, it includes a guide to grind vs. brewing method. If not, the capresso.com site includes PDF versions.


What is the correct way to eat biscotti with coffee?

Adapting "Golf is a good walk spoiled," (whoever said it; Twain probably didn't), biscotti is a sure way to destroy a good coffee.

Italians dip in wine instead, not in coffee according to that article. Dipping in that wine sounds marginally worse than dunking in coffee.

The soft, cookie-like biscotti available in many cafes won't hold up to any dunking at all, and will end up waterlogged and sad at the end of your sipping. The break-your-teeth traditional biscotti seem to call for something, but they don't seem edible to me. I prefer the middle-of-the-road, softer, chewy biscotti that can be enjoyed without submerging in liquid.

At the risk of this becoming an opinion-based discussion, for my money: If you want to drink coffee, just drink coffee.  If you want to eat a soggy cookie, eat a soggy cookie... but don't combine the two and risk ruining your perfectly good coffee in the process. :)


Does pre-heating a puck on the group head produce more crema?

Well, I've heard a lot of "pro tips" and advice having worked around espresso machines for a few years. And I must say, this one is new. I have never heard of warming the coffee itself. I can't imagine that, at the temperature at which the brew head usually resides, many significant changes are made in just a few moments of warming the coffee.

The closest I've heard to this is that some believe in the opposite. A fellow once told me to leave my spent puck in the portafilter if someone was going to be brewing again shortly. He claimed this helped retain heat in the portafilter. Though the science checks out, the results proved marginal and pretty much just made you the lazy guy using the espresso machine.

So, in closing, I'd say that the effects of warming your coffee are probably negligible, and that you can get more crema more easily through other means (buying better quality coffee, adjusting your brewing variables, etc)


So I got some roasted beans wet, how to dry them?

I would probably throw them out - I would just roast more - but I might also try and spreading them out on a flat tray that fits into the oven and turn it up to 200F (or lower) and let them sit in there until they are dry again. Just keep your eye on them and check frequently. If you start to smell them, they are probably past dry.

No idea how that will turn out, but my wife does a similar thing with crackers that have lost their crunchiness.


How can I maximize cold brew yield without harming flavor?

It generally depends on your brew ratio (# grams of coffee to # grams of water) some people go with 1:6, 1:7, etc.

And keep in mind the higher your ratio is the less concentrated the coffee will be, so for example if you brew 140 grams of coffee at the 1:7 ratio you would need to add about 980ml of water which would produce a larger yield than it would if you used the 1:6 ratio, but the later one would be more concentrated.

I also saw some people that use a lower ratios then dilute the yield with water to make it less concentrated.


Do ground beans or brewed coffee lose flavour faster?

In the scenario given, you don't have the prefect solution to drink fresh coffee. However, I would opt for carrying a brewing solution (French-press in your case) with me. Let's discuss the two cases separately.

1. Early-brewing

In that case, you can grind fresh beans and prepare your coffee optimally with the brewing method of your preference. However, you cannot protect the brewed cup of coffee to go 'bad'. The reason is, whatever you do, you leave tiny coffee grounds in the water and they continue the extraction process. By time, your coffee gets bitter as a result of over-extraction.

Actually, this is a problem even in our daily routine. Pour-over brewing methods are invented for that. We mostly use paper filters to filter out most of the tiny grounds and have a clean cup to get rid of continuing extraction. Thus, we can have a stable cup while we drink in the next five minutes.

If you follow your taste buds, you can clearly feel this in a Turkish coffee cup or French-press, as most of the tiny grounds are still in the final cup in a French-press (and all of them are still there in a Turkish fincan) you should be quick to drink it. Otherwise, the cup goes crap. (By the way, inverted French-press is can also be used to minimize the effect of tiny grounds. But not effective enough.)

2. Late-brewing

Everybody on this board could admit that after grinding coffee goes stale in a few minutes. (See How quickly does coffee get stale?)

When you grind the beans, the surface area increases so the delicious aromatics evaporate more easily. You probably will end up with a duller coffee experience at the end. However, I feel like over-extraction is a far worse problem in your case.


Does this look like a decent coffee grinder?

It looks like a burr grinder, as opposed to a blade grinder. Burr grinders give a more consistent grind size, which is why they're preferred over blade grinders.

My guess is it's made of steel, but it does look tarnished. You might take it apart and polish it to create a smoother grinding surface.

The wood on the inside might be difficult to clean of coffee oils and impart an odor to your freshly ground coffee.

I can't tell if the mechanism has a means of changing the grind size. If not, it may in fact be an old spice mill. Otherwise, it won't allow you much variety when grinding your coffee.

If it's given a little TLC I think it would make a nice vintage manual grinder. Compared to blade grinders, even this older grinder ought to do a better job than they ever could. However, if you can't change the grind size than you'll be limited in the type and quality of the coffee you can brew using it.


How do I design a Turkish coffee mixture?

There is no recipe for preparing a perfect blend.

Before beginning, please read this somewhat relevant question first:

What are the basics of creating an espresso blend?

I, personally, prefer to use Ethiopian Harrar single origin beans, light-to-medium roasted. However, this may all depend. When you go to a commercial Turkish firm, they mostly consume Dos Santos beans from Brazil, which itself is a kind of blend itself, and roast them to charcoal.

To prepare a Turkish blend, all you need to know is the characteristics of the brewing technique (See this previous post for a discussion) as you can see in the previous post. Opposite to the espresso, Turkish brewing is the least acidity revealing technique out there as it uses decoction. Therefore,

you can safely use acidic beans
you don't need to roast a lot to get rid of acidity
and, as a result, you can taste the fruitful notes, go for fruity beans
you may safely try dry/honey processed beans

Then, about the chemicals... You should not put any additional chemicals in it. It should be just ground coffee. I know some commercial products that already mix some herbs or sugar with fine ground coffee; but it has nothing to do with the reality apart from marketing. Think of it as 3-in-1 instant coffee products. You probably don't want to drink them.


Getting the sound of really good micro bubbles

The sound it's not a very good "measure stick" for steaming. That is because it would depend on the steaming wand (how many steam holes has, how much steam the machine produces, etc), the pitcher (the form of it affects in how the milk moves inside), the milk (yes, whole-milk vs almond are very different), etc...

So, I suggest to you that don't focus on other's people steaming sound, but instead on theirs technique. Of course there are some sounds that indicates some process (the first sound it's very loud, until the milk circulates enough), but there aren't a sufficient parameters (on my POV).

You can check this related answer. Hope it's helpful.


There are a few reasons why you might not get a good crema:

Stale coffee
Coffee not ground fine enough
Pressure too low

With a steam-powered espresso machine (especially if it's an entry level machine), you will typically not reach high enough pressure to get a proper crema. The crema is formed by oils extracted from the ground coffee, which needs high pressure (something like 9 bars). Your steam-powered machine will probably not produce more than ~3 bars of pressure.

Tamping with a spoon also seems not ideal, because it will be very difficult to achieve an even tamp. I cannot comment on how important that is for this particular machine, but with higher end pump machines it might lead to channeling and uneven extraction.


What's the rationale behind this placement of the pressure gauge?

It's likely connected there to ensure only cold water goes to the gauge.
Over time, hot water would negatively affect the gauge and, in a capillary tube, more rapidly deposit minerals and clog.


What's the recommended method for heating cold brew?

The best result I got was warming up in a bain-marie. No science here---just my trials... I believe for now that bain-marie preserves more flavours and "respects" the aromas.

Heating cold-brew coffee was surprising to me the first time. Such unexplored flavours with the exact same beans I use for drip, etc. I hope you'll enjoy, and explore for more questions here!


Should I thoroughly clean the portafilter basket between shots?

There's a trade-off here. If you're working in a fast-paced coffee shop, you're likely to favour the faster option (knock out the coffee) over cleaning. Generally knocking out the coffee will get rid of >99% of the grounds from the previous pull, so the impact on the flavour of the next one will be so slight as to be unnoticeable. Usually the portafilter won't even have time to dry out, so the coffee won't dry on and clog up the portafilter.

If you're making multiple coffees one after another, reusing the portafilter is probably acceptable.

However if you're leaving the coffee machine alone, it's best to at least rinse out the portafilter before you (or the next person) comes to use it. Once the grounds/coffee start to dry, it'll clog up and be much harder to clean further down the line.