Wheat bran

One US cup of wheat bran weighs between 58 and 64 grams, depending on how the cup is filled and which source measured it. That range is the answer; a single number would not be. Every figure behind it is below, with the method each source used.

Also called unprocessed wheat bran, miller's bran, crude wheat bran, raw wheat bran, Bob's Red Mill wheat bran.

Two sources 10.36 percent apart, just outside the 10 percent milled tolerance, so this entry publishes the range rather than a single figure. USDA FoodData Central publishes Wheat bran, crude (SR Legacy) at 1 cup = 58 g, implying a density of 0.2451 g/mL. King Arthur's Ingredient Weight Chart lists 'Wheat bran' at 1/2 cup = 32 g, extrapolating to 64 g per cup and 0.2705 g/mL. The USDA figure is confirmed by multiple independent USDA-data mirrors.

At this range, wheat bran is the lightest food this site tracks. Dried apple dice publish at 86 g per cup (density 0.36 g/mL); wheat bran at 58 to 64 g per cup (density 0.24 to 0.27) is meaningfully lighter still. The physical reason is straightforward: wheat bran consists of thin sheet-like flakes, the outer layer of the wheat kernel stripped off during milling, typically 2 to 5 mm across and under 1 mm thick. These flakes stack irregularly with substantial air gaps between them, more like uncrushed breakfast cereal flakes than like flour granules. A cup of wheat bran contains a large fraction of air by volume even when scooped loosely.

The gap between USDA and King Arthur is close to the site's milled tolerance boundary because wheat bran is unusually sensitive to fill method. Sheet-like flakes can pack flat-on-flat (dense) or edge-on/random (loose), similar to the orientation sensitivity documented for pumpkin seeds on this site but more extreme because bran flakes are lighter and more compressible. Slight tapping, shaking, or hand-packing can shift the cup mass by 10 to 15 percent. USDA's 58 g per cup is consistent with a loose scoop; King Arthur's 64 g per cup is consistent with a lightly-settled fill. Neither source documents its method.

Wheat bran contrasts sharply with wheat germ, published elsewhere on this site at 115 g per cup (density 0.49). Both are separated from the wheat kernel during milling, but germ is a granular embryo tissue that packs like coarse flour, while bran is a flake product that packs like a light cereal. The two products are often confused in home baking but have very different weights per cup and different nutritional profiles: germ is fat and protein rich; bran is nearly all insoluble fiber.

Product variants: crude (unprocessed) wheat bran is the raw milling byproduct, sold under brands like Bob's Red Mill. Miller's bran is another common name for the same product. Toasted wheat bran undergoes light heat treatment for stability and flavor and packs at slightly higher density due to moisture loss, but the difference stays within measurement precision. Wheat bran breakfast cereals (All-Bran, Kellogg's Bran Buds, Post Bran Flakes) are distinct fortified products with added sugar, malt, and other ingredients; they pack differently and are covered by separate cereal entries when added. Oat bran, rice bran, and corn bran are botanically distinct products with different densities and would earn their own entries.

Wheat bran is placed in the milled category alongside other granular and flake grain products. The category rule tracks physical packing behavior: flakes and coarse particles pack by scoop with air gaps in the same way as flours and whole grains, even at very low apparent densities. The 10 percent category tolerance applies here, and the 10.36 percent observed gap exceeds it by a small margin.

No standards body publishes a bulk density for wheat bran. Codex Alimentarius does not have a dedicated commodity standard for wheat bran at the time of publication. Two authoritative sources with a just-over-tolerance gap and no method documentation to arbitrate, so this entry is held at low confidence and range-published until a third independent source or a documented fill method resolves the disagreement.