Soy sauce: why 255 g per cup is wrong
USDA SR Legacy "Soy sauce made from soy and wheat (shoyu)" (FDC 174277) publishes 255 g (9 oz) per US cup of soy sauce. This site rejects that figure and publishes 278 g (9.8 oz) instead, from Kikkoman Soy Sauce, 150 mL bottle (distributor technical sheet, France) (density 1.1733 g/mL, matching the composition of the substance). The reason:
USDA's own record lists 5,493 mg of sodium per 100 g, about 14% salt, plus another 15% of dissolved protein, sugars and other solids from the soybeans and wheat. A plain 14% salt brine on its own weighs 1.10 g/mL, about 260 g per cup, before any of those other solids are added, so soy sauce cannot weigh 1.078 g/mL. Kikkoman's 150 mL bottle holds 176 g (1.173 g/mL), Kikkoman's specification gives specific gravity 1.17, and Health Canada and Japanese measuring tables weigh soy sauce at 1.15 to 1.20 g/mL.
The arithmetic
| Source | 1 cup | Density | Status |
|---|---|---|---|
| USDA SR Legacy "Soy sauce made from soy and wheat (shoyu)" (FDC 174277) | 255 g9 oz | 1.0778 g/mL | Rejected on physics |
| Kikkoman Soy Sauce, 150 mL bottle (distributor technical sheet, France) | 278 g9.8 oz | 1.1733 g/mL | Published here |
The published figure and its sources
The full sourcing for soy sauce, including every accepted and rejected figure, the state or filling method behind each, and the physics or standards reasoning applied, is on the ingredient page.
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