Tamari vs Soy Sauce: Wheat, Gluten-Free Labels and Allergen Lines
Tamari and soy sauce sit side by side on the shelf, often in look-alike bottles, and the words “gluten-free” appear on some of them and not on others. This explainer covers what separates the two on the label: whether wheat is in the ingredient list, what the FDA requires before a soy sauce can say “gluten-free”, and how the allergen lines for wheat and soy work. The worked example is San-J Organic Tamari Soy Sauce, Gluten Free.
How we wrote this: the gluten-free rules come from the FDA regulation 21 CFR 101.91 and the FDA questions and answers on gluten-free labeling. Allergen rules come from the FDA page on food allergies. Product details come from the San-J product page. We read the label and the rules; we did not lab test or taste test anything. Recipes and labels change, so the bottle in your hand is the final word.
Tamari vs soy sauce: the short answer
Tamari is a style of soy sauce, so the real question is what a given bottle is brewed from. The FDA describes soy sauce as a food ordinarily made by fermenting a mixture of soybeans and wheat, and notes that some soy sauces are not made with wheat. The word on the front of the bottle does not settle which kind you have. The ingredient list and the allergen statement do.
| Label point | Typical soy sauce | Tamari labeled gluten-free |
|---|---|---|
| Grain in the ingredient list | Usually wheat, alongside soybeans | No wheat, or wheat with the FDA asterisk statement (see below) |
| “Gluten-free” claim | Generally not allowed if brewed with wheat | Allowed when the 21 CFR 101.91 definition is met |
| Allergen statement | Names wheat and soy | Names soy |
| Where to check | Ingredient list, the “Contains” line and any gluten-free mark | |
What “gluten-free” means on a US label
Under 21 CFR 101.91, gluten-containing grains are wheat, rye and barley, including their crossbred hybrids. A food may say “gluten-free” when it does not contain:
- an ingredient that is a gluten-containing grain,
- an ingredient made from one that has not been processed to remove gluten, or
- an ingredient made from one that has been processed to remove gluten, if using it brings the food to 20 parts per million (ppm) gluten or more.
A food that inherently has no gluten also qualifies. In every case, any unavoidable gluten must be below 20 ppm. The same rule covers “no gluten”, “free of gluten” and “without gluten”, so those phrases are held to the same definition.
Why soy sauce gets its own rule
Soy sauce is fermented, and the regulation recognizes that a lab test may not give a reliable gluten number for fermented or hydrolyzed foods. Since a 2020 amendment, a maker of such a food that says “gluten-free” must keep records showing the food met the gluten-free definition before fermentation, that it checked its process for gluten cross-contact, and that it has controls in place where cross-contact could happen. Those records must be kept for at least two years and shown to the FDA on request.
The FDA questions and answers apply this directly to soy sauce:
- Soy sauce made from soybeans and wheat, or another gluten-containing grain, generally may not bear a “gluten-free” claim.
- Soy sauce not made with wheat or another gluten-containing grain can bear the claim.
- Soy sauce made with a grain that was processed to bring gluten below 20 ppm before fermentation can bear the claim too.
Wheat on a gluten-free label: the asterisk rule
That last case means a gluten-free soy sauce could still list wheat. When a food says “gluten-free” and also lists wheat in the ingredients or in a “Contains wheat” statement, the word wheat must carry an asterisk (or similar symbol) pointing to this statement near the ingredient list: “The wheat has been processed to allow this food to meet the Food and Drug Administration (FDA) requirements for gluten-free foods.” If you see wheat on a gluten-free bottle, look for that line. If you avoid wheat itself, not just gluten, a bottle that lists wheat is not the one for you, whatever the front says.
Wheat and soy allergen labeling
The Food Allergen Labeling and Consumer Protection Act of 2004 (FALCPA) named eight major food allergens, and wheat and soybeans are both on the list. Sesame became the ninth on January 1, 2023. Packaged foods that contain a major allergen must name the allergen source on the label. Regular soy sauce brewed with wheat will therefore name both wheat and soy, and a wheat-free tamari will still name soy, because soybeans are its base.
Two points to keep in mind. First, “gluten-free” and “wheat-free” are different questions: the gluten rule is about gluten levels, while the allergen rule is about whether wheat is an ingredient. Second, the FDA says it has not set a threshold level for any allergen. If someone in your home has a food allergy, read the full label every time you buy, since recipes and facilities can change.
Worked example: San-J Organic Tamari
Here is how the label points above look on San-J Organic Tamari, using the brand’s product page:
- Ingredients: water, organic soybeans, salt, organic alcohol (to preserve freshness). No wheat or other gluten-containing grain is listed, and the brand says it is made with 100% whole soybeans and no wheat.
- Allergen line: the brand states that the product contains soy ingredients.
- Gluten-free claim: the brand says it is certified by the Gluten-Free Certification Organization (GFCO). It also lists Non-GMO Project certification and describes the sauce as vegan and kosher.
- Nutrition Facts: a 1 tbsp (18 g) serving lists 10 calories, 0 g fat, 2 g protein, 940 mg sodium (39% Daily Value), 0.7 mg iron (4% DV) and 130 mg potassium (2% DV). The 10 fl oz bottle holds about 20 servings.
- Taste and uses: the brand describes it as richer and milder than regular soy sauce and suggests it for stir-fries, marinades, dipping, soups, dressings and glazes. That is the brand’s description, not our tasting.
Reading the Nutrition Facts panel works the same way for tamari as for any pantry item; our guide to reading a Nutrition Facts label explains serving size and %DV. If you compare two soy sauces, compare them per tablespoon, using each bottle’s own panel.
How to choose between tamari and soy sauce
- Read the ingredient list first. Wheat or no wheat is the main label difference.
- Check the “Contains” line. It should name soy, and wheat if wheat is used.
- Look for the gluten-free claim if you need it. Under FDA rules, the word on the label carries the 20 ppm definition. A third-party mark such as GFCO is the certifier’s own program on top of that.
- If a gluten-free bottle lists wheat, find the FDA asterisk statement, and skip it if you avoid wheat as an allergen.
- Compare per tablespoon using each bottle’s Nutrition Facts panel.
- Check seals that matter to you, such as organic or kosher. Our Non-GMO Project vs USDA Organic guide explains what those seals cover.
FAQ
Is all tamari gluten-free?
Not by name alone. Whether a bottle can say “gluten-free” depends on its ingredients and processing under 21 CFR 101.91, so check the ingredient list and look for the gluten-free claim on the label.
Is regular soy sauce gluten-free?
Generally not. The FDA says soy sauce made from soybeans and wheat may not bear a “gluten-free” claim, unless the grain was processed to bring gluten below 20 ppm before fermentation.
Can a gluten-free soy sauce list wheat?
Yes, if the wheat was processed to meet the gluten-free definition. The label must then mark wheat with an asterisk pointing to the FDA statement quoted above.
Does tamari contain soy?
Yes. Tamari is a soy sauce, so it is made from soybeans and will name soy as an allergen. San-J, for example, states that its tamari contains soy ingredients.
Can I swap tamari for soy sauce in a recipe?
Both are soy sauces and are used in the same kinds of dishes, such as stir-fries and marinades. Flavor varies by brand, so taste as you go.