Sweet Rice Flour

One US cup of sweet rice flour weighs 160 grams. Going the other way, 100 grams is about 0.62 cups.

Also called mochiko, glutinous rice flour, sweet white rice flour, sticky rice flour, mochi flour, mochigome flour.

TL;DR: 1 cup of sweet rice flour weighs 160 grams. High confidence, based on triple convergence between Koda Farms (Mochiko), Bob's Red Mill, and USDA's Branded Foods database. King Arthur's 120 grams per cup figure is rejected — it is 33 percent below the producer convergence and reflects the same fluid-ounce measurement error corrected in the regular rice flour entry.

Sweet rice flour is milled from glutinous short-grain rice, a distinct variety of rice (Oryza sativa var. glutinosa) grown for its sticky texture. It goes by many names, all referring to the same product: mochiko (Koda Farms's trademark and the dominant US brand name), glutinous rice flour, sweet white rice flour, mochi flour, and sticky rice flour. Both common names are misleading. It is not sweet in the sugar sense; the 'sweet' descriptor is a translation artifact. And 'glutinous' refers to the sticky, glue-like texture the cooked starch produces, not to gluten protein — sweet rice flour is naturally gluten-free.

The defining characteristic is the starch composition. Regular rice contains roughly 80 percent amylopectin and 20 percent amylose; glutinous rice is nearly 100 percent amylopectin, with almost no amylose. Amylose is the linear starch molecule that produces firm, separate cooked grains; amylopectin is the branched form that produces stickiness. This is why mochi holds together as a chewy paste rather than falling apart like cooked long-grain rice. In gluten-free baking, sweet rice flour is prized as a binder and moisture retainer, and it is a common component of gluten-free flour blends alongside regular rice flour, sorghum flour, and starches. It also thickens sauces and gravies without breaking on reheating.

The source data converges tightly. Koda Farms lists Mochiko at 30 grams per 3-tablespoon serving on the nutrition panel, which extrapolates to 160 grams per US cup. USDA's Branded Foods database entry for the same product (UPC 074823000219) explicitly reports 160 grams per US cup and 169 grams per metric cup. Bob's Red Mill Sweet White Rice Flour, made from the same base ingredient, lists 40 grams per quarter-cup serving on their label, extrapolating to the same 160 grams per cup. Three independent producers and one USDA database entry all agree.

King Arthur's ingredient chart lists glutinous rice flour at 120 grams per cup — the same figure they use for all-purpose wheat flour. That is a 33 percent shortfall against the producer convergence, and it repeats the pattern already documented in the regular rice flour entry, where King Arthur's 142 grams per cup was corrected to the producer figure of 160 grams per cup. The most plausible explanation is that King Arthur's chart treats every 4 1/4 ounce entry as if the ounces are fluid ounces (which would give 120 grams), rather than weighing the actual product. Sweet rice flour is milled finer than AP wheat flour and its amylopectin-dominant starch packs more densely, so the true weight per cup is substantially higher.

For practical baking, weigh sweet rice flour at 160 grams per cup. A recipe calling for one cup of glutinous rice flour or mochiko wants 160 grams, not the 120 grams that a King Arthur-based conversion would suggest. The gap is enough to noticeably affect mochi texture, gluten-free bread structure, and sauce thickening ratios. This flour is not interchangeable by volume with regular white rice flour in traditional Asian recipes — behavior in the mouth and on the tongue differs sharply — but by weight the two flours are close enough that some gluten-free blend recipes use them interchangeably.

The following published figures for sweet rice flour are rejected here, with the physics or standards reasoning behind each rejection on its own page:

• King Arthur Baking ingredient weight chart: 120 g per cup