What is the seed in coffee?

In botanical terms, the coffee bean is a seed - the reproductive embryo of the coffee plant, contained within the fruit (the coffee cherry). What we call a "bean" is technically the seed of a drupe: the innermost structure of the cherry, protected by silverskin, parchment, mucilage, pulp, and outer skin.

A standard coffee cherry contains two seeds, facing each other with their flat sides pressed together - which is why most coffee beans have that characteristic flat face. When only one seed develops and the other fails to form, the single seed grows rounder and fuller without the constraint of a twin: this is a peaberry.

Understanding the seed structure matters for processing: every stage of post-harvest work - pulping, fermenting, washing, drying, hulling - is systematically removing the layers surrounding the seed to reveal it in its green state, stable and ready for export and roasting. The quality of that seed - its density, moisture content, and cellular integrity - is the product of everything that happened during the plant's growing season, and the raw material from which all roasting and brewing quality ultimately flows.