Most cheese contains very little whey protein. During cheesemaking, over 96% of the whey proteins in milk are drained off with the liquid whey, leaving behind a curd made almost entirely of casein, the other major milk protein. So while cheese starts as whole milk (which contains both casein and whey), the finished product is overwhelmingly a casein food.
How Cheesemaking Removes Whey
Milk protein is roughly 80% casein and 20% whey. When an enzyme or acid is added to milk, the casein molecules clump together into solid curds. The liquid that separates out, called whey, carries away the whey proteins along with water, lactose, and some minerals. This separation is the fundamental step in all cheesemaking, and it’s why cheese and whey protein end up as essentially different products from the same starting material.
The curds are then pressed, salted, and aged to become cheese. The whey liquid, once considered waste, is now dried and processed into the whey protein powders sold as supplements.
How Much Whey Protein Stays in Cheese
The amount varies by cheese type, but it’s consistently small. In hard and aged cheeses like cheddar or parmesan, the casein-to-whey protein ratio can reach as high as 98:2. That means only about 2% of the protein in those cheeses comes from whey. For cheesemaking aimed at firm or hard varieties, the goal is specifically to maximize casein and minimize whey protein in the final product, because whey interferes with the texture and aging process.
Softer and fresher cheeses retain slightly more whey protein, but still far less than the original milk. Fresh spreadable cheeses use a combination of enzymes and acid to coagulate the milk, which traps a bit more whey in the curd, though the difference is modest.
The Exception: Ricotta and Whey Cheeses
Ricotta is the notable outlier. It’s not made from curds at all. Instead, it’s made by reheating the leftover whey liquid and collecting the proteins that coagulate at high temperatures. This makes ricotta a genuinely whey-based cheese. A typical whey ricotta contains about 7.5% protein by weight, and that protein is predominantly whey protein rather than casein.
Other traditional whey cheeses exist in various cultures, including Norwegian brunost (brown cheese) and Italian ricotta salata. These are all made from the whey stream rather than the curd, so they flip the usual protein profile. If you’re specifically looking to get whey protein from a cheese source, ricotta is your best option.
Processed Cheese Adds Whey Back In
Here’s where things get interesting. Processed cheese products, like individually wrapped slices and cheese spreads, often contain added whey protein that wouldn’t naturally be there. Manufacturers include whey protein concentrate, whey powder, or whey cheese alongside casein-based ingredients. This practice originally started as a way to use a cheaper protein source, but whey protein concentrates have become comparable in price to casein ingredients. Today, they’re included more for functional reasons: whey proteins change the melting behavior and texture of processed cheese in ways manufacturers find desirable.
If you’re reading ingredient labels on processed cheese, look for terms like “whey protein concentrate,” “whey powder,” or “whey” in the ingredients list. Natural cheeses (cheddar, Swiss, gouda, brie) won’t have these additions. Processed cheese foods and cheese products frequently will.
What This Means for Milk Protein Sensitivities
People with cow’s milk allergies react to specific proteins, and whey proteins (particularly one called beta-lactoglobulin) are common triggers. Because aged, natural cheeses contain so little whey protein, some people with milk allergies can tolerate them when they can’t tolerate milk itself. Research on fully matured cheeses like Parmigiano-Reggiano has found that while the whey protein content drops during aging, it doesn’t disappear entirely. Samples still contained measurable amounts of beta-lactoglobulin regardless of how long they aged.
Tolerance varies significantly between individuals. Some people with confirmed cow’s milk allergy have tolerated aged hard cheeses without issue, while others have experienced severe reactions. Milk allergy can involve immune responses to multiple different proteins, not just whey, so the lower whey content in cheese doesn’t guarantee safety. The casein that makes up most of cheese protein is itself a common allergen.
Cheese vs. Whey Protein Powder
If your goal is consuming whey protein for muscle building or recovery, cheese is not an efficient source. A 30-gram scoop of whey protein powder typically delivers 20 to 25 grams of whey protein. To get that same amount from cheddar cheese, where whey makes up roughly 2% of total protein, you’d need to eat an impractical quantity. Cheese is an excellent source of protein overall, but that protein is casein, which digests more slowly than whey and has a different amino acid release profile.
Casein has its own benefits. It provides a sustained release of amino acids over several hours, which is why some athletes consume casein-rich foods before bed. But it’s a different protein with different properties than whey, and treating cheese as a whey protein source misses this distinction.