Curd is obtained by coagulating milk in an exceedingly serial method referred to as curdling. It will be a final foodstuff or the primary stage in cheesemaking. The action will be caused by adding organic compound or any edible acidic substance like juice or vinegar, and so permitting it to coagulate. The enhanced acidity causes the milk proteins (casein) to tangle into solid lots, or curds. Milk that has been left to bitter (raw milk alone or milk with else carboxylic acid bacteria) will naturally turn out curds, and bitter milk cheeses area unit made this fashion. manufacturing cheese curds is one among the primary steps in cheesemaking; the curds area unit ironed and drained to variable amounts completely different|for various} kinds of cheese and different secondary agents (molds for blue cheeses, etc.) area unit introduced before the specified aging finishes the cheese. The remaining liquid, that contains solely whey proteins, is that the whey. In cow's milk, ninety p.c of the proteins area unit caseins.