Soy sauce

One US cup of soy sauce weighs 277.6 grams (9.8 ounces). Going the other way, 100 grams is about 0.36 cups.

Also called shoyu, soya sauce, regular soy sauce, naturally brewed soy sauce, koikuchi shoyu, Kikkoman soy sauce.

Condiments and sauces compared: cup weights side by side, the source behind each, and why they differ.

A cup of soy sauce weighs 277.6 g (9.8 oz), a density of 1.17 g/mL, so a tablespoon weighs 17.3 g, not the 14.8 g of a tablespoon of water. Kikkoman's 150 mL bottle holds 176 g, and Health Canada and a Japanese kitchen table weigh soy sauce at 1.15 to 1.20 g/mL. USDA's 255 g per cup is lighter than the salt brine inside soy sauce and is rejected.

Soy sauce is brewed from soybeans, wheat, salt and water: the mash ferments for months, then is pressed and pasteurised. Japanese-style soy sauce (koikuchi shoyu), the kind Kikkoman makes and most American recipes mean, is about 14 to 17% salt, with another 15% or so of dissolved amino acids, sugars and other solids from the beans and grain. Kikkoman's specification for its gluten-free soy sauce gives 13.9% salt and at least 33% total soluble solids.

That composition settles the weight. Salt is the densest thing in the bottle: a plain brine of 14% salt already weighs 1.10 g/mL, about 260 g per cup, before any of the other solids are added, and everything else pushes the density higher. Kikkoman's 150 mL bottle has a net weight of 176 g, which is 1.173 g/mL and 277.6 g per cup. Kikkoman's gluten-free specification gives a specific gravity of 1.17, 276.8 g. Health Canada's Nutrient Value of Some Common Foods weighs 15 mL of soy sauce at 18 g, 1.20 g/mL or 284 g per cup at whole-gram precision, and the measuring table published by Meiji in Japan gives a 200 mL cup of shoyu as 230 g, 1.15 g/mL or 272 g per US cup. The four figures sit within 4.4% of each other, inside the 5% tolerance this site allows for liquids. Kikkoman's bottle, weighed to the gram, is published.

The US label points the same way without stating a weight. Kikkoman's American bottle gives the serving as 1 Tbsp (15 mL), the FDA reference amount for a major condiment, with 960 mg of sodium. At USDA's 5,493 mg of sodium per 100 g, 960 mg is 17.5 g of sauce, 1.165 g/mL.

USDA's Standard Reference record for shoyu (FDC 174277) gives 1 cup as 255 g, 1.078 g/mL. The same record lists about 14% salt and 15.2 g of ash per 100 g. A liquid carrying that much salt cannot weigh less than the brine alone, so the cup figure is rejected and has its own correction page. USDA's survey database repeats it as 16 g per tablespoon, and the FAO density database's 1.12 g/mL comes from an older edition of that survey; both are too light for the same reason. USDA's low-sodium record carries the identical 255 g cup.

Practical guidance: use 277.6 g per cup, 69 g per quarter cup, 17.3 g per tablespoon and 5.8 g per teaspoon. For a stir-fry sauce written in tablespoons the difference from water weight is small; it matters when a recipe in grams is scaled up, or when sodium is counted by weight. Reduced-sodium soy sauce carries less salt and should weigh a little less; tamari and Chinese dark soy sauce are different products with their own weights.

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

• USDA SR Legacy "Soy sauce made from soy and wheat (shoyu)" (FDC 174277): 255 g per cup