No, most soy sauce is not gluten free. Traditional soy sauce is brewed with roughly equal parts wheat and soybeans, making it off-limits for anyone avoiding gluten. However, several specifically labeled gluten-free versions exist, and understanding the differences can help you pick the right bottle.
Why Most Soy Sauce Contains Wheat
Standard soy sauce, the kind you’ll find in most grocery store aisles and on restaurant tables, is brewed from a mixture of soybeans, wheat, water, and salt. Wheat typically makes up about half of the grain mixture and plays a key role in developing the sauce’s flavor, color, and aroma during fermentation. Brands like Kikkoman’s original recipe, Lee Kum Kee, and most store brands all use wheat as a core ingredient.
Some people assume that because soy sauce is fermented, the gluten gets broken down enough to be safe. This is a risky assumption. The FDA has acknowledged that gluten proteins in fermented and hydrolyzed foods are no longer intact and cannot be adequately detected or quantified through standard testing. But “hard to detect” is not the same as “gone.” For a fermented product to carry a gluten-free label, the FDA requires manufacturers to demonstrate that the ingredients were gluten free before fermentation began, not simply that gluten can’t be measured in the finished product. The definition of gluten free remains the same: below 20 parts per million.
Tamari: The Closest Gluten-Free Match
Tamari is a Japanese-style soy sauce traditionally made with little or no wheat. Gluten-free tamari is brewed with 100% soybeans and no wheat at all, giving it a richer, more full-bodied flavor with over 30% more umami than typical soy sauces. The deeper flavor comes from a higher concentration of soy protein in the brewing process.
One important caveat: not all tamari is wheat free. Some brands add small amounts of wheat, so you still need to check the label. Look for tamari that explicitly says “gluten free” on the packaging. San-J, for example, produces a well-known gluten-free tamari brewed without wheat.
Gluten-Free Soy Sauce From Major Brands
Several mainstream soy sauce brands now offer dedicated gluten-free versions. Kikkoman’s gluten-free soy sauce swaps wheat for rice, using just four ingredients: water, soybeans, rice, and salt. It’s traditionally brewed the same way as their standard sauce, so the flavor profile is familiar even though the grain base is different. This makes it one of the easiest swaps if you’re used to regular soy sauce and want something that tastes close to what you know.
Certification Levels Vary
If you have celiac disease or a high sensitivity to gluten, pay attention to whether a product is simply labeled gluten free or also carries a third-party certification seal. The FDA’s threshold for a gluten-free label is below 20 parts per million. The three main certification organizations in the United States all require stricter limits. The Gluten-Free Certification Organization (GFCO) and the Gluten-Free Certification Program (GFCP) both cap products at 10 parts per million, while the Celiac Support Association (CSA) requires products to test below 5 parts per million.
A certified product gives you an extra layer of assurance through independent testing and auditing that goes beyond what the FDA label alone requires.
Other Soy Sauce Alternatives
If you want to skip soy sauce entirely, whether for gluten concerns or a soy allergy, two popular alternatives are coconut aminos and liquid aminos.
- Coconut aminos comes from the sap of the coconut plant, not from coconuts themselves. It’s both soy free and gluten free, with a slightly sweeter, milder flavor than soy sauce. It works well for people dealing with both soy and wheat allergies.
- Liquid aminos is made from soybeans but contains no wheat, making it gluten free while still delivering a soy-based flavor. It tends to be high in sodium, similar to regular soy sauce.
Watch the labeling here. Some brands call their coconut-based products “coconut liquid aminos” or just “liquid aminos,” which can create confusion with soy-based liquid aminos. Always check the ingredient list to confirm what you’re actually buying.
Reading Labels at Restaurants
The trickiest situations tend to happen when you’re eating out. Most restaurants use standard soy sauce containing wheat, and it often shows up in marinades, stir-fry sauces, dressings, and glazes where you might not expect it. Asking specifically whether a dish contains soy sauce, and whether it’s a gluten-free version, is the most reliable way to avoid an accidental exposure. Many Asian restaurants keep tamari on hand as an alternative, but you’ll need to ask rather than assume.