Soy sauce (醤油 shōyu / 酱油 jiàngyóu / 간장 ganjang) is the primary liquid seasoning of East and Southeast Asian cuisine: a thin, dark, intensely savoury liquid produced by fermenting soybeans with salt and a mould culture (Aspergillus oryzae), often with added wheat.
Production
The traditional process (honjozo): soybeans are cooked, mixed with roasted wheat, inoculated with Aspergillus mould to produce koji, then mixed with salt brine to form a mash (moromi) that ferments 6–18 months. The mature mash is pressed to extract liquid, which is pasteurised and bottled. The flavour reflects the fermentation duration and ratio of soy to wheat.
Rapid production methods (using hydrolysed vegetable protein + added caramel) produce a chemically similar but organoleptically different product in days rather than months. These are cheaper and lower quality.
Major types
Japanese (shōyu)
- Koikuchi (dark soy, standard): wheat-heavy, the default Japanese cooking and table soy sauce
- Usukuchi (light soy): paler colour but saltier; used in dishes where colour must be controlled
- Tamari: little or no wheat; thicker, richer; the traditional gluten-free soy sauce option
- Saishikomi: double-brewed; very dark, sweet, and complex; for dipping
Chinese
- Light soy (生抽, shēngchōu): thinner, saltier; the default Chinese cooking soy sauce; different from Japanese usukuchi despite the shared ‘light’ description
- Dark soy (老抽, lǎochōu): aged longer, thicker, sweeter from added molasses; used for colour in red-braised dishes; less salty than light soy
- Sweet soy (kecap manis): Indonesian; thick, palm-sugar sweetened; used in dishes like nasi goreng
Korean (ganjang)
- Guk-ganjang (soup soy): lighter, made from meju (fermented whole soybeans), saltier and more pungent; traditionally used for soup seasoning
- Jin-ganjang (general soy): modern Korean soy sauce, closer to Japanese style
Cooking with soy sauce
Light and dark soy sauces are not interchangeable by volume. Dark soy sauce colours dishes dark brown with relatively little saltiness; using it at light soy sauce quantities will produce bitter over-salted results. When a recipe calls for ‘soy sauce’ without specification, Japanese koikuchi or Chinese light soy is the default.
Soy sauce added early in cooking produces a deeper, more integrated flavour; added at the end it tastes brighter and more distinct. Both approaches are correct for different applications.