Buckwheat flour

One US cup of buckwheat flour weighs 120 grams. Going the other way, 100 grams is about 0.83 cups.

Also called whole groat buckwheat flour, dark buckwheat flour, gluten-free buckwheat flour, sarrasin flour.

Two authoritative sources agree exactly. USDA FoodData Central SR Legacy (FDC 170687, Buckwheat flour, whole-groat) publishes a cup at 402 kcal and 100 g at 335 kcal, back-calculating to a cup weight of 120 g and density of 0.5072 g/mL. King Arthur's Ingredient Weight Chart lists buckwheat flour at 120 g per cup, an exact match. Both sources publish the same figure, so this entry publishes 120 g per cup at medium confidence.

Perfect agreement between two independent authoritative sources is unusual on this site and worth noting. The comparable entry for brown rice flour publishes as a range of 128 to 158 g per cup because USDA and King Arthur disagree by 23% for that ingredient, driven by grind fineness variation between brands. Buckwheat flour does not show the same disagreement. This likely reflects two factors: buckwheat flour is a smaller commercial category than rice flour, with fewer brands and more consistent processing standards; and the whole-groat versus light-flour distinction is clearer in the industry, so both authoritative sources are measuring the same product specification (whole-groat, including the darker outer layers of the seed).

USDA Branded Foods records confirm the baseline. Hodgson Mill buckwheat flour lists 30 g per 1/4 cup serving, extrapolating to exactly 120 g per cup, matching USDA SR Legacy and King Arthur. Bob's Red Mill Organic buckwheat flour lists 37 g per 1/4 cup, extrapolating to 148 g per cup, which is higher and likely reflects a coarser or organic-specification grind. This is single-brand outlier variation rather than industry-wide disagreement, and it does not warrant a range publish here.

Buckwheat is a pseudocereal, not a true grain. It is the seed of the Fagopyrum esculentum plant, a member of the Polygonaceae family (same family as rhubarb and sorrel), unrelated to wheat despite its name. It contains no gluten and is a staple of gluten-free baking, most iconically in Russian blini, French galettes de sarrasin, and Japanese soba noodles. American home baking most commonly uses it in pancakes and muffins, often blended with wheat flour to soften the earthy flavor.

Whole-groat buckwheat flour, the product covered here, includes the darker outer hull fragments and has a stronger flavor, darker color and higher fiber content than light buckwheat flour (which is milled from hulled groats only and is closer to white in color). USDA's SR Legacy record specifies whole-groat; King Arthur's chart does not distinguish variety, but their generic 'buckwheat flour' figure agrees with USDA's whole-groat measurement exactly. Light buckwheat flour is a separate product not covered by this entry; its density is not published in the sources this site currently uses.

Buckwheat flour sits in the milled category alongside all other flours. The 10% category tolerance applies, and the observed 0% gap between authoritative sources is far inside it. Two sources agreeing exactly is stronger evidence than two sources agreeing within tolerance, so this entry would move to high confidence with the addition of a single independent standards body reference, though none currently exists for buckwheat flour density.

Related products not covered by this entry: kasha (roasted whole buckwheat groats) is a distinct product with different density because the groats are whole rather than milled. Buckwheat groats (raw) are another distinct product. Soba flour is typically buckwheat blended with wheat and would require separate sourcing. No standards body publishes a bulk density for buckwheat flour. Codex Alimentarius standards for buckwheat cover moisture content, defect tolerances and grading rather than physical density.