gristmill

Gristmill is a facility where grain, typically wheat or corn, is ground into flour or meal. Traditionally powered by water or wind, gristmills use a pair of millstones to grind the grain; the upper stone (runner) rotates above the lower bedstone while grain is fed through a hopper into the eye (central hole). As the runner turns, grain is ground between the stones and flour is drawn away through outlets.

The basic components include a power source (water wheel, turbine, or windmill), gearing to reduce speed and increase torque, the pair of stones, a hopper and chute, and flour and bran channels. The efficiency and fineness of grinding depend on stone quality, the gap setting between stones, and grain moisture. Most mills also included sieves or sifters to separate flour from bran and middlings.

Historically, gristmills emerged in antiquity and became widespread in medieval Europe and Asia, often located along rivers where water power could drive the wheel. Watermills and windmills expanded with technology; by the 18th and 19th centuries, larger mills served regional markets. The development of roller mills and steam-powered mills in the industrial era gradually reduced reliance on traditional stone-ground milling, though stone-ground flours remain popular in artisan contexts.

Today, many historic mills survive as museums or heritage structures and some continue production on a small scale. Gristmills played a central role in agricultural economies by turning grain into a storable, transportable product and by concentrating local labor and trade around milling sites.