How is chocolate made?

Pods are cut by hand and split open, and the beans are removed with their sweet white pulp. Piled in heaps or boxes, the pulp is colonised by yeasts and then bacteria; the heat and acid kill the seed and break down its cell walls, letting the bean's own enzymes create the flavour precursors. The beans are then dried slowly for about a week, which lets residual acid evaporate out.

Roasting drives the Maillard reaction between the amino acids and sugars that fermentation produced, generating the aromas we recognise as chocolate. The beans are cracked, the shell blown away by airflow, and the remaining nib ground until friction releases its cocoa butter and the solid becomes a fluid — chocolate liquor.

Chocolate liquor either goes forward into chocolate, with sugar and possibly milk added, or it is pressed to separate cocoa butter from the solids. The pressed solids become cocoa powder. Every cocoa product on a shelf came out of one of those two paths.

Refining reduces particle size below the roughly 25 microns at which the tongue detects grain. Conching agitates the warm chocolate for hours or days, driving off harsh volatiles and coating every particle in fat. Tempering controls which crystal form the cocoa butter sets in — the reason chocolate snaps and shines. Moulding casts and cools it.

Each step depends on the last. Roasting an unfermented bean produces no chocolate flavour because there is nothing to convert. Conching cannot fix a coarse refine. Tempering has no effect on flavour at all. Understanding which step causes which characteristic is how you work backwards from a disappointing bar to what went wrong.