Coffee beans are the seeds of a fruit often called a cherry.

The longer version

What drinkers call a coffee bean is the seed inside a small red or purple fruit that grows on an evergreen shrub. Each fruit usually holds two seeds, flat sides facing each other, surrounded by sweet pulp and a thin skin. Farmers remove the pulp before drying, since leaving it on encourages fermentation that spoils the flavor.

The flat groove running along each seed is where the two halves developed against one another. Because the beans are seeds, they contain the stored food a seedling would need, and roasting transforms those stored sugars and proteins into the aromatic compounds associated with brewed coffee. Roasting also drives off water and makes the brittle texture that grinding depends on.

Where this entry sits

Everyday ingredients turn out to be full of quiet chemistry and long history. This collection gathers short, plain explanations of how bread rises, why onions sting, where common spices originate, and how coffee, tea, and chocolate reached the modern kitchen. The full list sits on the Food and Drink page, where every entry is listed in order.