Recycling, when you come right down to it. It’s a type of cheese that’s classically made from the waste whey leftover from the manufacture of firmer cheeses. It can be made from cow’s milk, sheep’s milk…goat, buffalo, you get the picture. In Italy there are dozens of styles of ricotta. However what’s common to them all is the method by which they’re made.
You need not be familiar with the intricacies of cheese manufacturing — merely Little Miss Muffet — to know that the cheese making process yields two main components: curds and whey. The curds are what you get when you combine rennet (enzymes) with warm or hot milk or cream. The rennet causes the curd-making proteins known as caseins to draw together into clumps. In the process they trap a good deal of the fat. The masses this clumping action creates are called curds. They’re skimmed off, drained, salted, put in forms and ripened into the firm cheeses we know.
So what about the whey, then? It’s the milky liquid that’s left behind after the curds are skimmed off. It contains proteins of its own, only those proteins aren’t effected by rennet. They are however effected by a couple of other things: heat and acid. When heated the whey proteins, especially those that go by the name of lactoglobulin, uncoil. If the environment is acidic, those lactoglobulin molecules become attracted to one another. The result is again a bunch of clumps that trap remaining fat and form curds. However because whey proteins are a good deal smaller than their casein cousins, the curds they make are quite a bit smaller.
Are they still good eatin’? You bet, and a great way to extract additional food from what would otherwise be a waste product (kudos to whomever figured out this re-cooking “ri-cotta” process, oh so long ago).
Yet all this raises a question: if you’re not making ricotta out of leftover whey, is it still ricotta? I believe the answer is an unequivocal yes. Even if your starting point is a richer milk mixture, you’re still making the same whey (not casein) cheese via the same heat-and-acid method. The curd size is the same, only the fat content is higher. That’s a difference, however to argue that a homemade ricotta isn’t ricotta because it has a higher fat content is like arguing that whole milk isn’t milk because you’ve always made do with skim.
Of course it’s fair to argue which one is more traditional. It’s even fairer to argue which one you prefer. But just because Italian peasants were forced to make their ricotta with leftover, fat-depleted whey, why must we? It doesn’t follow, especially when higher fat ricotta scores quite a bit higher on the deliciousness scale.