Black beans

One US cup of black beans weighs 194 grams (6.8 ounces), measured dry, uncooked. Going the other way, 100 grams is about 0.52 cups.

Also called black turtle beans, turtle beans, dried black beans, dry black beans, frijoles negros.

Dried beans, lentils and peas compared: cup weights side by side, the source behind each, and why they differ.

A cup of dry black beans weighs 194 g (6.8 oz), and a cup of cooked, drained black beans 172 g (6.1 oz). USDA's two black bean records and the USDA Food Buying Guide fall within 10% of each other, so this entry publishes USDA's figure for black beans. Confidence is medium because all three are USDA sources.

Black beans, also called black turtle beans, are a small, shiny, oval variety of the common bean (Phaseolus vulgaris), the same species as kidney, pinto, navy and Great Northern beans. They are a staple of Latin American and Caribbean cooking and keep their shape well when cooked.

USDA SR Legacy has two raw records. "Beans, black, mature seeds, raw" (FDC 173734) gives 1 cup = 194 g at 11% water; "Beans, black turtle, mature seeds, raw" (FDC 175186) gives 184 g. The USDA Food Buying Guide, which lists the bean as "Black (Turtle beans)", gives 1 lb dry as 2 1/4 cups, 202 g a cup. The three span 9.6%, inside the 10% tolerance for whole seeds, and the 194 g record sits in the middle. America's Test Kitchen does not settle it: its Black Bean Soup gives 1 pound as 2 1/2 cups (181 g a cup) and its Vegetarian Black Bean Soup as 2 cups (227 g), so neither is entered as a figure.

The physical check: Paixão, Corrêa and colleagues (2020) measured a medium-sized Brazilian common bean of the carioca type in bulk at 779 to 831 kg per cubic metre, 184 to 197 g per cup, the higher figure at the drier end of a range still wetter than store beans. Black beans at 194 g, 0.82 g/mL, sit inside that band. Size matters in a container as small as a cup: its walls leave gaps around large beans that smaller ones fill. That is why black beans weigh more per cup than the larger kidney beans (184 g) and less than the smaller navy beans (208 g).

Cooked: USDA's boiled black bean record (FDC 173735) weighs a cup at 172 g, 66% water, and the boiled black turtle record (NDB 16017) at 185 g; the two sit 7.6% apart, so 172 g is published for cooked beans. Cooking roughly triples the volume: the Bean Institute gives 1 cup of dry beans as about 3 cups cooked and drained, and a 1 lb bag as about 6 cups.

Practical guidance: use 194 g per cup of dry black beans, 97 g per half cup; a 1 lb bag holds about 2 1/3 cups. Use 172 g per cup of cooked, drained beans. A 15-ounce can, drained, gives about 1 1/2 cups by America's Test Kitchen's count and 1 3/4 cups by the Bean Institute's. Pick dry beans over for small stones, rinse them, and soak them or not as the recipe says.