Cottage cheese

One US cup of cottage cheese weighs 226 grams. Going the other way, 100 grams is about 0.44 cups.

Cottage cheese is one of the few 227-per-cup ingredients on this site where the number is physically reasonable, and it is worth reading alongside cream cheese and sour cream (also close to 227 g/cup) rather than alongside milk, yogurt and buttermilk (where the same number is wrong).

King Arthur publishes 1/2 cup at 113 grams, which extrapolates to 226 grams per cup and a bulk density of 0.9553 grams per millilitre. USDA FoodData Central publishes 1 cup at 226 grams (FDC 172179, Cheese, cottage, creamed, large or small curd), giving the same density. The two sources agree exactly, well inside the 5 percent liquid category tolerance.

The reason cottage cheese sits below water density is not composition but structure. On mass fractions alone, cottage cheese is roughly 79 percent water, 12 percent protein, 4 percent fat and 3 percent carbohydrate — a mixture that should have a density around 1.06 grams per millilitre based on the density of each component (protein at 1.35, fat at 0.92, carbohydrate at 1.5, all averaged by their proportions). The measured bulk density is much lower because cottage cheese is not a homogeneous liquid. It is discrete curds with whey between them, and packing curds into a measuring cup leaves small air pockets that no amount of pressing eliminates. Those air pockets bring the effective density down to about 0.95, close enough to 8 fluid ounces per cup that the 226-gram figure is right for physical reasons rather than accidental ones.

This distinguishes cottage cheese from milk, buttermilk, yogurt or pumpkin, all of which are homogeneous liquids or pastes that pack without air gaps and therefore weigh their true density per cup. It puts cottage cheese in the same bucket as cream cheese, sour cream and Greek yogurt — semi-solid dairy products where curd structure or high fat content pulls the bulk density below water.

The entry describes the standard creamed cottage cheese as sold in a tub (4 percent milkfat, small or large curd). Lower-fat and non-fat variants weigh slightly more per cup because water replaces fat and water is denser than fat. USDA publishes 2 percent milkfat cottage cheese at 220 grams per cup and 1 percent at approximately 226 grams (values shift with product formulation and whey retention). Dry-curd cottage cheese, sold without added cream, weighs about 145 grams per cup because there is no dressing to fill the gaps between the curds — it is drier and looser. These variants are not covered by this entry but are worth knowing about if a recipe specifies which type.

Related products: ricotta is a whey cheese with a similar appearance but different composition (usually higher fat, no whey between curds) and denser at about 250 grams per cup. Farmer's cheese is closer to dry-curd cottage cheese but with less whey remaining. Quark, popular in European baking, is a fresh cheese cultured from skim milk and sits denser than cottage cheese at about 240 grams per cup because it has no curd-whey structure.

FDA identity standards for cottage cheese are at 21 CFR 133.128 (dry curd cottage cheese) and 21 CFR 133.129 (creamed cottage cheese). Both address composition and manufacturing rather than density. USDA AMS grading specifications for cottage cheese are covered under 7 CFR Part 58. The Codex Alimentarius standard for cottage cheese (CXS 273-1968) is the international counterpart.

The category here is 'liquid' rather than 'sugar' or 'milled' because cottage cheese behaves as a semi-liquid in a measuring cup: it self-levels when scooped in, the whey fills gaps as the curds settle, and the density is set by the composition and structure of the product rather than by how it was scooped. The 5 percent liquid category tolerance applies. Both sources sit exactly on the same figure, so no range is needed.