Yogurt

One US cup of yogurt weighs 245 grams. Going the other way, 100 grams is about 0.41 cups.

Also called plain yogurt, whole milk yogurt, natural yogurt, curd (dahi).

The King Arthur figure for yogurt reproduces the same volume-to-weight conversion error already documented on the milk entry. King Arthur's chart lists 1 cup at 8 ounces and 227 grams, which are the same measure expressed twice, once as fluid ounces and once as if those fluid ounces were weight ounces. The gram figure implies 0.9595 g/ml, which is lighter than water.

Yogurt is a fermented milk product with the same base composition as milk (roughly 85% water carrying protein, lactose and minerals in solution and suspension) plus additional bacterial biomass and lactic acid, and it is necessarily denser than water for the same reason milk is. The value is rejected under rule 7 rather than deleted, because a published figure that is wrong is worth knowing about, and this one needs no standards body to refute: the density of water is enough. USDA FDC 171284 (Yogurt, plain, whole milk) gives a cup at 245 g, or 1.0356 g/ml.

This is slightly denser than whole milk (1.0313 g/ml on the milk entry), which is what fermentation produces: converting some of the lactose to lactic acid increases the density of the water phase, and the addition of bacterial biomass raises total solids by a small amount. USDA also lists FDC 170886 (plain low fat yogurt) at 245 g per cup and FDC 170887 (plain skim milk yogurt) at 245 g per cup, and the cup portion is the same across all three fat levels because the removed fat is replaced by proportionally more of the dissolved solids that fat displaces. This is the same effect documented on the milk entry between whole and 1% milkfat.

The 8-ounce single-serving container that is standard in US supermarkets weighs 227 g, and this appears to be the origin of the King Arthur figure: the volume of an 8-fluid-ounce serving read as if it were a weight. That serving is one cup by volume but under-weighs the actual cup content by about 7% for the reason described above. Greek yogurt is a separate product covered by a separate entry.

It is strained plain yogurt with much of the whey removed, which concentrates the milk solids and raises the density substantially, typically to 1.05-1.08 g/ml depending on how thoroughly the strain was performed. Chobani, Fage and similar brands publish per-cup weights between 227 and 245 g depending on style, but these do not indicate a lighter product; the label serving is often standardised at 227 g regardless of true cup weight. Skyr, labneh, quark and other cultured dairy products are related but distinct and are not covered by this entry.

Sweetened, flavoured and fruit-added yogurts have their own weights that vary by product and are outside the scope. That leaves one accepted source. The entry is held at medium confidence until an independent second and third are found.

Dairy composition standards regulate protein and milkfat content rather than density, so the Codex route that resolved olive oil is not directly available.