Grind distribution

The spread of particle sizes produced by the grinder during a single grind. Ideally, most particles are close to the target size — a "tight" distribution. Wide distributions contain both very fine and very coarse particles.

Why it matters — Uniform grinds extract evenly. Wide distributions produce simultaneous under- and over-extraction — fines over-extract while boulders under-extract — and the cup tastes muddled.

Good to know

• This is the single biggest reason premium grinders outperform cheap ones. Burr quality, alignment, and motor speed all affect distribution.
• A WDT tool doesn't change distribution, but it does even out the puck so that uneven grind has less impact on the brew.