Whey

Whey is what leaves. FAO’s teaching line: cheese is the solid part of milk (curds) separated from the liquid part (whey) ¹. Milk proteins split: casein about 75–80% of total protein, whey proteins about 20–25%. Ordinary cheesemaking coagulates casein; whey proteins mostly stay in the liquid ¹. Lactose stays there too, which is why young whey tastes sweet and later whey tastes more lactic as cultures work.

U.S. cheddar identity writes drainage as procedure: the mass is cut, stirred, and heated to promote and regulate the separation of whey and curd; then the whey is drained off ². See Curd.

Why the amount you leave behind matters #

FAO: too much whey in the curd makes it sour; they also warn that taking too little whey out of a fresh cheese can leave it easier for unwanted bacteria to attack — and they usually remove more whey from fresh cheese than from cheese meant for ripening ¹. Moisture you keep is composition you will live with. CDR lists moisture with fat, pH, and salt as the tests on every vat ³.

Cloudy whey early is protein still escaping as fines. Clearer whey means the network captured more of what you meant to keep ¹.

What you can still do with it #

FAO’s small-scale notes use leftover whey as a drink (fruit or herbs), a cooking liquid for grain or pulses, or a cooked brown whey cheese (mysost) reduced until nearly solid ¹. Heating whey to gather remaining protein is the idea behind Ricotta — a different set than the casein gel. Do not treat those cooking notes as a U.S. safety process.

What to notice #

Look: clarity, color (green-yellow is ordinary), and whether curd bits are riding along. Taste: sweet to lactic. Smell: clean dairy, not dirty drain. Cheese-plant handling of whey is its own sanitation job; in the kitchen, whey is food. See Cheese and Milk.