Grind size is often overlooked when it comes to coffee brewing. If you have quality beans and are brewing with care (ratios, water, temperature, etc.) then don’t forget about grinding. This determines the coffee particles in your cup. If your grind size is too fine for your brew method, you’ll end up killing the sweetness and balance of your cup by over-extraction. And it can affect the taste in a variety of ways from harsh and astringent, to dull and flat. Brew some espresso-ground coffee in a percolator and you’ll get what we’re talking about.
Here is a quick overview of grinder types and grind sizes for different brew methods.
Grinder Selection: Blade vs. Burr. Blade (mill) grinders are the most common--the one you’ve had in your cabinet for years that has a single blade at the bottom that spins to grind your coffee. The problem with these, as you’ve likely noticed, is that they produce an extremely uneven grind, defeating the whole point of proper grind size.
Retire it. And invest in a proper burr grinder, I promise you won’t regret it.
Burr grinders have two cutting discs that allow for a wide range of adjustment. Either manual or electric burr grinders will prove to be a worthwhile investment, though electric burr grinders are really preferred for grinding coffee for espresso. We use the Baratza Encore in our cupping lab, which is a bit pricey, but a tried-and-true machine in the coffee world.
Grind Size. Again, this depends on the brew method you’re using. You can think of grind size as directly correlated to the amount of time your coffee is in contact with water. The finer your coffee, the shorter your brew time. Espresso, the fastest brew method, uses essentially the finest grind (save for Turkish coffee). Cold brew, the slowest method, uses the coarsest grind.
Extra Coarse. You should only use a coarse grind when making cold brew or when practicing other brew methods where the coffee will be spending an extended period of time in water. Cold brewing extraction time: 12-18 hours.
Coarse. A coarse grind is recommended for french press, with a brew time of around 4 or 5 minutes.
Medium-Coarse. This grind size is most often used for infusion brew methods like Chemex (4 minutes) or your classic countertop drip coffee maker (4-5 minutes).
Medium. A medium grind can also be used for your countertop coffee maker, as well as for Siphon brewers, Aeropress and some pour-over methods (about 3 minutes).
Medium-Fine. This is the ideal grind size for classic cone shaped pour-over methods like the Hario V60 (3 minutes) and other Siphon methods (with a slightly shorter extraction time).
Fine. Finely ground coffee is used for any quick extraction brew method. A fine (or ultra fine) grind is recommended for espresso and other quick extractions like a one-minute Aeropress brew