Why is grind size important in brewing coffee?

Grind size plays a crucial role in the extraction rate of the coffee during the brewing process. When coffee grounds are brewed, water extracts flavor compounds, oils, acids, and caffeine from the coffee. The surface area of the coffee grounds directly impacts how quickly these desirable elements are leached out into the water.

Finer grind sizes increase the surface area exposed to water, leading to a faster extraction rate, while coarser grinds have less surface area, resulting in slower extraction. If the grind size is too fine for the brewing method being used, it can lead to over-extraction, causing the coffee to taste bitter; conversely, if the grind is too coarse, under-extraction may occur, resulting in a weak and sour flavor profile.

Therefore, adjusting the grind size according to the brewing method is essential for achieving the desired flavor and strength in the final cup of coffee.