What Exactly Is Whey?

Separating curd from whey
Getty Images/John Burke

"Little Miss Muffet sat on a tuffet, eating her curds and whey; along came a spider, who sat down beside her and frightened Miss Muffet away"

We've all heard the nursery rhyme, but what exactly is whey?

Whey is the liquid that is expelled from cheese curds during the cheesemaking process.

First, starter culture is added to the milk. The culture thickens the milk, then rennet is then added to further encourage coagulation.

As the milk coagulates, curds form. The curds are then cut so they expel moisture (whey).

For soft cheeses, the curds are cut into large pieces. For harder cheeses, the curds are cut into tiny pieces. This is because the smaller a curd is, the more liquid it releases. This liquid is whey.

Sometimes, whey is discarded after the cheesemaking process, which is a shame because it's full of protein and nutrients. According to Steven Jenkins in The Cheese Primer, another reason not to discard whey is that it increases the amount of algae in sewers and rivers when poured down the drain. Luckily, whey can be used for other things. It can be fed to animals, be used to make other dairy products and foods, or be processed into a concentrated form and added to protein powder, protein bars or processed foods as "whey proteins". Some specific ways to use fresh whey include:

  • Making ricotta. Traditionally, ricotta was always made from whey, not milk. Ricotta means "recooked" because the cheese is a product made from milk that has already gone through the cheesemaking process. Italian ricotta is usually made from whey derived from sheep's milk and American ricotta is typically made from whey derived from cow's milk.
  • Use whey in place of water or milk in recipes. This includes bread and other pastries and savory items. You can also use whey instead of water to boil pasta, rice, etc.
  • Use whey to soak grains before cooking them, or to soak steel cut oats overnight
  • Add whey to smoothies

If you want to get your hands on some fresh whey, then try making cheese at home.

Some types of cheese to try:

If you make homemade yogurt and thicken it by letting it drain in a cheesecloth, you can use the "yogurt whey" in the same ways that cheese whey is used.