Starch has been separated from the proteins and other materials in grains since ancient times. The Romans called it amylum, which meant “not ground at the mill.” They made it by grinding wheat in a mortar and then soaking the flour for days, during which bacteria grew and digested the grain’s cell walls and gluten proteins while leaving the dense, solid starch grains intact. They reground the dregs, and then pressed them through fine linen, which retained the small grains. The starch grains were dried in the sun, and then either cooked in milk or used to thicken sauces (p. 583).