Soy sauce is a traditional fermented liquid condiment produced from soybeans (Glycine max), wheat, salt, and water via a multi-stage process involving Aspergillus oryzae or sojae molds (koji), followed by lactic acid bacteria and yeasts. The fermentation hydrolyzes soy proteins into free amino acids (notably glutamic acid for umami), peptides, and organic acids while generating sugars, ethanol, and hundreds of volatile Maillard reaction products. The resulting dark brown mixture has pH ~4.5-5.0, ~15-20% salt, and complex aroma from phenols, esters, and pyrazines. It is not a single chemical entity but a heterogeneous aqueous solution used globally for seasoning. Studies highlight antioxidant peptides and potential cardiovascular effects in moderation.