Coffee grind size is perhaps the most important thing to get right when making a brew, but hundreds of different gadgets and gizmos make it hard to know where to start. And that’s not even to mention the numerous overly complicated online guides using the same terms to mean completely different things…
As decent, coffee-loving people, we understand that the stakes are high. After all, every exasperated home-brewer is another potential win for instant coffee. As instant coffee is just plain wrong, we thought we’d weigh in on this issue with our guide to grind size.
What is grind size?
Different brewing methods require a different size grind of coffee. The grind size itself is the measure of the individual grains of coffee. These sizes have to be changed with different brewing methods (French press, espresso etc.) because of the surface area. A very fine grind will increase the surface area of coffee, whereas larger grounds will have the opposite impact.
You may be wondering why different preparation methods are even necessary, and you wouldn’t be alone… A lot of this is down to personal preference and convenience, but the tastes also changes. Different brewing methods highlight different aspects of the beans, and some roasts are better suited to each of these. For example, a filter coffee will usually deliver a much ‘cleaner cup’ (bright and vibrant) when compared with a French press, and so therefore is usually roasted a little bit lighter. Similarly, the darker roasts typically favoured for espresso will give a much stronger, more bitter taste.
Grind size is hugely important as this impacts the taste of your brew. Too fine, and the water will struggle to pass through the grounds, making bitter over-extracted sadness. Too coarse, and the coffee will be watery and undrinkable.
However, it is not just the grind size that is important. Uniformity between grinds is also vital. If the grounds are all different sizes, some will be over-extracted and others will be under-extracted. This will leave you with a bitter-sour cup of coffee and a sad look on your face. Burr grinders are great for ensuring uniformity, as the burrs can be moved closer or further apart to increase or reduce the size. This is not the case for blade grinders, which blend the coffee into an uneven mess. This is a recipe for disappointment. Please don’t do this.
What is the ideal extraction time for coffee?
Coffee extraction times vary considerably between brewing methods. For espresso this is typically between 25-30 seconds, whereas for French press it is a much longer 4 minutes. This is all to do with the grind size, and the amount of extraction necessary because of it.
An espresso that extracts in under 20 seconds is more likely to taste sour and nasty. Anything longer than 35 seconds, and youll be left with something unpleasantly bitter. Because of the way espresso works – with huge amounts of pressure pushing water through fine particles – it can extract a large amount of intense flavour and coffee oils very quickly.
A pour-over filter coffee will also vary in extraction time. For example, paper filters usually slow the passing of water more than mesh inserts. Typically, a paper-filter coffee will take between 2 and 3 minutes to brew. Any longer will cause bitterness, and any less will leave you with watery coffee and in a bad mood.
For French press, the coarse grounds should be left to steep for 4 minutes. As the coffee grounds remain in the carafe the entire time, the coffee should be drunk immediately after plunging to avoid bitterness from over-extraction.