Don’t let people fool you. Size DOES matter! That is, when it comes to your coffee grounds.
It might not seem like grind size would matter – I mean, it’s all the same bean, right? WRONG! The wrong size has the potential of ruining the most perfect cup of coffee. Imagine a beautiful Geisha tasting sour because your barista didn’t carefully control the size of the grounds before making your pour-over. At this very moment, I honestly can’t imagine anything worse.
Coffee extraction, without getting too science-y, is the process of bringing out soluble flavors from coffee grounds by exposing them to water. The ideal extraction yield is 18-22%, which is largely controlled by the size of the grind. If beans are ground too coarse, they can be under-extracted, leading to a sour taste. This is because the acids are extracted early while the other balancing flavors might not have the opportunity to be brought out. If beans are ground too small, they can be over-extracted, which might sound like a good thing because more flavor! But the truth is it results in a bitter taste that masks all the goodness that coffee could have been because the bitter components continue to be extracted long after the acids and sugars.
To what size you grind your beans is dependent on how you plan to brew your coffee. For instance, due to the shorter brew time and intense method of extraction, espresso is much finer than grounds would be for a French press, which are typically coarse due to its extended brew time and the way its filtered. A drip machine requires a medium grind while a pour-over might be just a bit finer. The finest grind is typically reserved for Turkish coffee (a method of preparation, not the product itself) where the grounds are so fine you can’t individually tell them apart, and oftentimes you need a specialized grinder to produce this size.
When I first started trying to brew specialty coffee at home, I figured step 1 would be getting myself a grinder. However, I did not do my research, and instead went with one of the cheapest options on Amazon- a blade grinder (the HORROR!). I would have been better off buying pre-ground beans from the grocery store. First off, the grounds produced by my blade grinder were uneven, meaning an uneven cup of coffee – some grounds would be under-extracted while others over-extracted. Second, there was no way to control grind size, so my brew options were limited. Third, blade grinders require a lot of heat and friction to grind the beans which affects the taste of the grounds. Safe to say, my coffee always tasted off. Most people in the coffee industry recommend a burr grinder, but if that’s too much of an investment right now, a simple hand grinder where you can control the grind size will suffice.
Clearly there are other factors that play an important role in the taste of your coffee, such as roast, water quality, and brew time. However, we can’t downplay the fact that size matters when it comes to your grounds.
Stayed tuned, because soon in the Coffee Info section of our site we’ll provide a detailed breakdown of grind size for various brewing methods. Until then, consult your local barista if you have any questions – they know what they’re doing!