Soy sauce is a broad term for several subtly different concoctions. To find out what’s what, take a quick glance at the ingredient list on the label:
• If the ingredient list says soybeans, wheat, water, and salt, you’re probably getting a naturally brewed soy sauce (a.k.a. shoyu) that’s been aged for six months or longer in steel or plastic tanks or traditional wooden vats. Good stuff. Reduced-sodium versions of these are brewed in the traditional manner, and after fermentation, a dialysis process removes some salt but not the good flavor.
• If there’s caramel color, hydrolyzed soy or vegeetable protein, and corn syrup on the ingredient list, chances are you’re looking at a synthetic, or nonbrewed, soy sauce.
• If the label lists soybeans, water, and salt—but not wheat—what you have is tamari, a richly flavored traditional variation of soy sauce.