Why does grind size matter?
Grind size controls extraction speed: finer grinds expose more surface area and slow water flow (faster, stronger extraction); coarser grinds do the opposite. Match the grind to the method — espresso fine, pour-over medium, French press coarse — then adjust for taste.
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Every brewing problem and its fix runs through grind. Sour? Grind finer. Bitter? Grind coarser. This is because grind changes both surface area (how much coffee water can reach) and flow (how long water stays in contact). Each method has a target: espresso needs fine powder (25-30 seconds of pressure), pour-over needs sand-like medium, immersion needs coarse because the water sits for minutes, and cold brew coarsest of all because it steeps for hours. Consistency matters more than exact size — blade grinders shatter beans into dust-plus-boulders, so one cup contains every grind size and extracts unevenly no matter what you do. A burr grinder is the single highest-impact purchase in home coffee, ahead of kettles, drippers and even beans.
- ·Specialty Coffee Association brewing standards(No direct source link provided)