Curding

Part of speech: verb, noun

Definitions

1. Thickening and separating into solid lumps and liquid whey, as milk does when acid or rennet is added
2. Clotting into soft lumps while the watery portion splits away, the way milk sours or is treated to make cheese
3. Coagulating into semi-solid masses of protein, a process that happens when milk turns sour or is deliberately set

Etymology: "Curding" is simply the form of "curd" used as a verb and as a noun for the act of thickening, so the history that matters is that of "curd" itself. Its ancestor was the Middle English "crud" or "crudde", meaning a coagulated substance, and "curd" arose when the sounds of that older word were transposed, a process linguists call metathesis, in which the r and the u swapped places. Because "crud" and "curd" both descend from the same root, they are doublets: two forms of one word that split apart and took on separate lives. "Crud" kept the older spelling and gradually acquired its grubby modern sense of filth, while "curd" stayed with the idea of milk clotting into a solid mass. The verb "curd" grew naturally out of that noun, so "curding" describes milk, or anything else, thickening into lumps.

Synonyms: curdling, coagulating, clotting