By Harold McGee
Industrial producers have been making nonfermented approximations of soy sauce since the 1920s, when the Japanese first used chemically modified soy protein (“hydrolyzed vegetable protein”) as an ingredient. Nowadays, defatted soy meal, the residue of soybean oil production, is broken down—hydrolyzed—into amino acids and sugars with concentrated hydrochloric acid. This caustic mixture is then neutralized with alkaline sodium carbonate, and flavored and colored with corn syrup, caramel, water, and salt. Such quick “chemical” soy sauce has a very different character from the slow fermented version, and is usually blended with at least some genuine fermented soy sauce to make it palatable.