Black-eyed peas

One US cup of black-eyed peas weighs 167 grams (5.9 ounces). Going the other way, 100 grams is about 0.60 cups.

Also called black-eyed beans, blackeye peas, blackeyed peas, cowpeas, southern peas, lobia, dried black-eyed peas.

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

A cup of dry black-eyed peas weighs 167 g (5.9 oz), the lightest cup of any dry bean or pea on this site. USDA, the USDA Food Buying Guide, a cowpea study and Norway's food composition table fall within 9% of each other, so this entry publishes USDA's figure.

Black-eyed peas are not peas but cowpeas (Vigna unguiculata), a legume first domesticated in Africa, cream-coloured with a black eye around the hilum, where the seed was attached to the pod. In the American South they are cooked with pork as hoppin' John and eaten on New Year's Day for luck; they are also a staple across West Africa and in India, where they are called lobia.

USDA SR Legacy "Cowpeas, common (blackeyes, crowder, southern), mature seeds, raw" (FDC 173758) gives 1 cup = 167 g at 11.9% water. The USDA Food Buying Guide gives 1 lb dry as about 2 3/4 cups, 165 g a cup. Kabas and colleagues (2007, Journal of Food Engineering) measured cowpea seed from Antalya, Turkey, at a bulk density of 0.69 g/cm³, 163 g per cup. Norway's Matvaretabellen weighs 1 decilitre of dry black-eyed beans at 75 g, 177 g a cup. The four span 8.7%, inside the 10% tolerance for whole seeds.

The physical check: the same study explains why the cup is light. Kabas measured the seed itself at 1.13 g/cm³, with 38.9% of the bulk air between seeds. Packing is not the reason: lentils (Irvine and colleagues, 1992) and chickpeas (Konak and colleagues, 2002) leave about 44% air. What differs is the seed: lentil and chickpea seeds measure about 1.4 g/cm³, so a cup of them weighs more even though cowpeas pack a little tighter. At 167 g, the cup is 0.71 g/mL, and a pound fills about 2 3/4 cups, a quarter cup more than a pound of kidney or Great Northern beans.

Cooked: USDA's boiled record (NDB 16063) weighs a cup of cooked black-eyed peas at 171 g, 70% water, so a cup of cooked peas weighs about what a cup of dry ones does. That is a single source, so it is given here rather than published as a second state. Black-eyed peas cook faster than most dried beans, often in under an hour, and many cooks skip the soak.

Practical guidance: use 167 g per cup of dry black-eyed peas, 84 g per half cup and 42 g per quarter cup; a 1 lb bag holds about 2 3/4 cups. Use about 171 g per cup of cooked, drained peas. Rinse and pick them over before cooking. Fresh and frozen black-eyed peas hold far more water and are not covered by these figures.