How Important is Coffee Grind Size?
Grind size is a crucial factor that impacts the flavor of your coffee. It is just one of many variables that influence the taste of your brew. Other factors include the water temperature, the pressure of extraction, the surface area of the coffee grinds, and the method of brewing.
If you want to make the perfect shot of espresso, you need a fine grind size. This is because a lot of pressure is required to extract the shot. If you use a coarse grind size, the extraction process will be too fast, and there will be little to no pressure.
When making a pour-over or V60, you don't need as much pressure, so you can use a more coarse grind size. This is because using a paper filter requires a coarser grind size to allow the water to permeate through and extract the coffee drink. If you use a fine grind size with a paper filter, the coffee will be overextracted, resulting in a bitter flavor profile. The longer the water sits in the coffee grounds, the more overextraction occurs. This is because more surface area of the coffee grounds is exposed to the water.
Similarly, brewing fine ground coffee with a French Press can also result in over extraction. Fine coffee grounds have more surface area for the water to extract coffee during the brewing process than coarse grinds. Therefore, the grind size is connected to how your coffee will taste. Over extraction is a common cause of bitter and harsh flavors in coffee.