Buckwheat Groats

One US cup of buckwheat groats weighs 170 grams (6 ounces), measured raw (untoasted) whole groats, dry, spooned and leveled. Going the other way, 100 grams is about 0.59 cups.

Also called raw buckwheat groats, whole buckwheat, hulled buckwheat, buckwheat kernels, kasha, roasted buckwheat groats, toasted buckwheat.

A cup of raw buckwheat groats weighs 170 g (6 oz), and a cup of roasted groats, kasha, weighs 164 g (5.8 oz). USDA and King Arthur both give exactly 170 g for whole buckwheat, so this entry publishes that figure; USDA's roasted record gives 164 g.

Buckwheat (Fagopyrum esculentum) is not a wheat or any other grass. It is the seed of a flowering plant related to rhubarb and sorrel, cooked and eaten like a grain, which makes it a pseudocereal and naturally gluten-free. Groats are the hulled seeds: small three-sided pyramids, pale tan to green when raw. Roasted groats turn reddish brown and taste nutty; in Eastern Europe and in US shops they are sold as kasha, often by granulation: whole, coarse, medium and fine.

USDA SR Legacy "Buckwheat" (FDC 170286) gives 1 cup = 170 g, its only household measure, and puts the grain at 9.75% water, 13.3% protein and 10% fibre. King Arthur gives 1 cup of whole buckwheat at 6 oz, 170 g, an exact match, and its figure is accepted. USDA's "Buckwheat groats, roasted, dry" (FDC 170685) gives 1 cup = 164 g at 8.41% water.

The physical check: a firm, dry seed of starch and protein is roughly 1.3 times as dense as water, so 170 g in a 237 mL cup means the groats fill a little over half of it, the usual fill for small hard grains poured loosely. The neighbours on this site agree: whole quinoa weighs 170 g per cup and wheat berries 192 g. Roasting drives out a little more water and slightly puffs the seed, so a cup of kasha weighs a few percent less than raw groats, as USDA's two records show.

Labels give a heavier figure for a reason that has nothing to do with buckwheat. Bob's Red Mill's raw groats, Pure Indian Foods' groats and Wolff's whole-granulation kasha all print 1/4 cup as 45 g, which is 180 g per cup. The same 45 g quarter cup appears on many dry-grain labels, rice among them, a standard serving weight with the nearest measure beside it, so those labels are kept as sources but do not decide the figure. Both sit within 10% of USDA.

Granulation matters for kasha. The figures here are for whole groats. Coarse, medium and fine kasha are cracked pieces of the same seed, and smaller pieces fill the gaps between larger ones, so expect a cracked kasha to weigh more per cup than whole. Milling all the way to flour goes the other way: buckwheat flour on this site weighs 120 g per cup, because fine powder holds far more air than whole seeds.

Practical guidance: use 170 g per cup for raw groats, 85 g per half cup and 42 g per quarter cup; use 164 g per cup for whole roasted kasha. Bob's Red Mill cooks 1 cup of raw groats in 2 cups of water and 1 cup of its kasha in 1 1/2 cups. Rinse raw groats before cooking, and toast them in a dry pan for a few minutes if a recipe wants kasha's flavour, then measure by weight, since toasting changes the volume slightly.