How does grind size influence coffee extraction?

Grind size significantly influences coffee extraction primarily because it affects the surface area of the coffee particles in contact with water during brewing. When the coffee beans are ground finely, there is a larger surface area exposed, which allows for more efficient and quicker extraction of soluble compounds, flavors, and oils from the coffee grounds. This increased surface area maximizes the interaction with water, leading to a faster and more thorough extraction process.

For instance, in methods like espresso brewing, where water is forced through finely ground coffee under pressure, the finer grind allows for a quick and rich extraction, resulting in a concentrated flavor profile. Conversely, coarser grinds have less surface area, which may slow the extraction process, leading to under-extraction if the brewing time is not adjusted appropriately. Therefore, understanding and controlling the grind size is essential for achieving the desired flavor profile in different brewing methods.