Ricotta, a common lasagna filling, is what kind of cheese?

Ricotta, a common lasagna filling, is a whey cheese.

Unlike most familiar cheeses, ricotta is traditionally made from the whey left over after another cheese has been produced. That liquid still contains proteins, especially albumin and globulin. Cheesemakers heat the whey, often after allowing it to acidify, causing those proteins to form delicate curds that can be drained and collected.

The name ricotta means “recooked,” referring to this second heating of the dairy liquid. Traditional ricotta may use whey from sheep, cow, goat, or Italian water buffalo milk. Modern commercial versions sometimes add milk or are made largely from milk, but ricotta remains classified with whey cheeses because its defining traditional process recovers solids from whey.

Fresh ricotta is soft, white, mildly sweet, and highly perishable. It is used in savoury dishes such as lasagne, ravioli, calzone, and stuffed pasta, as well as desserts including cannoli and cassata. Aged forms exist too, including ricotta salata, which is firmer and salted. Ricotta’s light texture can cause confusion with cream cheese, but the two are made by different processes.