In the Water Project I'm studying water in spirits in cocktails, from the source water for fermentation through to the sparkling water we use to dilute drinks. As part of the latter research, I'm looking into deconstructing and reconstructing mineral water.
Much of the work on this has been done by other people and I'll just be reproducing it here. In short, the mineral content of mineral waters is publicly available, so you can add minerals to your own water to recreate your favorite brand.
You can either start with your tap water, taking into account its mineral content, and add more minerals to it (as done on the Khymos blog), or you can start with completely mineral-free water and add to that (as done in the Craft Cocktails at Home book).
What's in My Water?
I decided to look at San Francisco tap water to see what it contains. From the annual Water Quality Report we can see the standard minerals that we look at in bottled water including calcium, magnesium, and sodium. My local water also contains metals like copper, lead, and aluminum. Then it has added chloramine and fluoride for disinfectant and dental health.
I know my water tastes good even without filtering it, but is it appropriate for use to make mineral water? Most of the numbers in the water report are given in ranges, and some of those ranges are pretty wide. They also give average levels of minerals and contaminants. Some averages from the report are:
Calcium 49 ppm (parts per million)
Magnesium 4.9 ppm
Sodium 13.5 ppm
The average amount of Total Dissolved Solids (TDS) in my water 132 ppm. The TDS is an important number as we use it to measure mineral waters. Water sold as mineral water in the US has to have TDS of 250 at minimum.
Intrigued by the fact that my water seems to be halfway to mineral water, I decided to test the TDS of my tap water.
Testing Total Dissolved Solids (TDS)
TDS is super easy and cheap to test - a TDS meter costs about $15 on Amazon.com, or you can get one for free when you buy a Zero Water pitcher for $33. The pitcher is designed to get reduce the TDS in tap water to zero, so I bought one.
Using the enclosed TDS meter, I found that my tap water has super low TDS in the first place - only 32 ppm, compared with the San Francisco average of 132! I then compared it with filtered water:
San Francisco Tap Water, Average = 132 ppm
Camper's Tap Water = 32 ppm
Camper's Tap Water, after filtering with Mavea water pitcher = 28 ppm
Camper's Tap Water, after filtering with Zero Water pitcher = 0 ppm
Distilled Water (purchased), no minerals added = 0 ppm
I also tested Carbonated water, just to see how it reads, as most mineral waters that I'll be looking at later will be sparkling. It turns out that this is harder to read - the meter jumps around quite a bit and then settles around a number range. When I carbonated TDS 0 water it settled to 17 - 22 ppm. Interesting.
But what about the rest of the stuff in the water?
So even if I get the solids down to zero, what about the chloramine and fluoride? Are they still there and can you taste them? It turns out that the Zero Water pitcher gets rid of fluoride and some chloramine. From the FAQ:
Q. Does the ZeroWater filter remove Fluoride?
A. ZeroWater filters are not certified for the reduction of fluoride however fluoride is an inorganic compound. The TDS meter is designed to detect inorganic compounds. Fluoride levels in water are usually around 2 to 4 ppm, which will show up on the meter as 002 to 004. So when filtered water reads 000 it is not likely that fluoride is present in water.
Q. Does the filter remove Chloramine?
A. We have done internal lab testing that shows our filters can reduce chloramine. However, the presence of chloramine can reduce the expected life of the filter, so if you have chloramine in your water, you may need to change your filter more often than normal.
I then looked about getting rid of chloramine on the SF Water website:
Chloramine is not a persistent disinfectant and decomposes easily from a chemistry point of view but for water supply purposes chloramine is stable and it takes days to dissipate in the absence of substances exerting chloramine demand. Therefore, it is not practical to remove chloramine by letting an open container of water stand because it may take days for chloramine to dissipate.
However, chloramine is very easily and almost instantaneously removed by preparing a cup of tea or coffee, preparing food (e.g., making a soup with a chicken stock). Adding fruit to a water pitcher (e.g., slicing peeled orange into a 1-gal water pitcher) will neutralize chloramine within 30 minutes. If desired, chloramine and ammonia can be completely removed from the water by boiling; however, it will take 20 minutes of gentle boil to do that. Just a short boil of water to prepare tea or coffee removed about 30% of chloramine.
If desired, both chlorine and chloramine can be removed for drinking water purposes by an activated carbon filter point of use device that can be installed on a kitchen faucet.
Can you taste chloramine in drinking water? Several sites say that chloramine tastes better than chlorine in drinking water, but can you taste it at all?
"Chloramines do not give off any taste or smell and are relatively safe." [link]
The Water Quality Association, says [pdf]: "While chloramines are not a drinking water health concern to humans generally, their removal improves the taste and odor of drinking water. " They do not mention boiling but activated carbon filtration.
(Extra: A note about chlorine and chloramine removal in home brewing.)
So maybe you can taste chloramine, and better safe than sorry.
My guess is that if I boil water for 20 minutes to remove chloramine, then cool and filter it in the Zero Water filter, I could get pretty good quality water, with which to begin mineral water experiments.
Or, you know, just buy distilled water by the gallon at the store.
The Water Project on Alcademics is research into water in spirits and in cocktails, from the streams that feed distilleries to the soda water that dilutes your highball. For all posts in the project, visit the project index page.