Soy sauce, tamari and coconut aminos: what is gluten-free

Published 2026-10-21, updated 2026-10-21

Soy sauce looks like it should be gluten-free. It is made from soybeans, after all. In fact most soy sauce is brewed with roasted wheat as well as soybeans, which makes it one of the most common surprises for people starting a gluten-free diet. The wheat is part of the traditional recipe and contributes to flavour and aroma. Tamari, coconut aminos and a few other products are often used instead, but they are not all the same, and a tamari is not automatically safe. This guide explains how soy sauce is made, how the alternatives differ, how to read the label, and which other everyday condiments can contain gluten.

Why regular soy sauce contains wheat

Traditional soy sauce is made by mixing cooked soybeans with roasted wheat, adding a mould culture and salt water, and letting the mixture ferment for months. Many common soy sauces use roughly equal parts of soy and wheat, and some styles use more soy than others. Wheat gives the sauce a sweeter, rounder flavour, and because it is a main ingredient, it is not a trace amount. Even though fermentation breaks down some proteins, regular soy sauce is not considered gluten-free, and should be avoided on a gluten-free diet.

The label gives it away. In many countries wheat has to be declared as an allergen, so look for wheat in the ingredients list or in a bold allergen statement. The words soy sauce alone on a menu or in a recipe do not tell you whether it contains wheat.

Tamari: often but not always wheat-free

Tamari is a Japanese style of soy sauce traditionally made with little or no wheat, and it is often described as a gluten-free soy sauce. It tends to taste darker, thicker and a little less sharp than regular soy sauce. But the word on its own is not a guarantee. Some brands sold as tamari contain wheat, and others are made on shared equipment with wheat-based sauces. Some products are labelled as tamari soy sauce when they are simply a standard soy sauce.

Treat tamari as a product to check, not as a category that is safe. Look for a statement on the bottle such as gluten-free or wheat-free, and read the ingredients. The ingredients should list soybeans, water and salt, and perhaps alcohol as a preservative. The regulations for gluten-free claims differ between countries, so a label claim is more reliable than the word tamari.

Coconut aminos and other substitutes

Soy sauce and its gluten-free substitutes
Product	Made from	Gluten note	Flavour compared with soy sauce
Regular soy sauce	Soybeans, roasted wheat, salt, water	Contains wheat. Not gluten-free.	Salty, savoury, slightly sweet
Tamari	Mostly soybeans, salt, water	Often wheat-free, but check each brand and label.	Darker, rounder, less sharp
Labelled gluten-free soy sauce	Soybeans with another grain such as rice	Should be labelled gluten-free. Check for a label claim.	Close to regular soy sauce
Coconut aminos	Coconut blossom sap, salt	Usually gluten-free and soy-free. Check the label.	Sweeter, milder and less salty
Liquid aminos	Soybeans, acid or enzymes	Varies. Some brands are gluten-free, others are not.	Salty, similar to soy sauce

Coconut aminos is made from fermented coconut sap, and is the usual choice for people avoiding both soy and gluten. It is sweeter and less salty than soy sauce, so a recipe may need extra salt or a little acid. Because the saltiness differs, swap it in to taste instead of measure for measure. Whichever you use, season in small additions, since all of these products are salty.

Reading the label

Look for a gluten-free claim on the bottle. It is the most useful single signal.
Read the ingredients. Wheat, barley, rye, malt, and unspecified grain or cereal are the words to look for.
Check the allergen statement, since in many countries wheat appears in bold or under a contains line.
Check the may-contain statement. Rules for these vary by country and are often voluntary.
Check again when you change brand or buy a new bottle, because recipes and factories change.
In restaurants, ask whether the soy sauce used is gluten-free. Table soy sauce and sauce in sushi, noodle, stir-fry and marinade dishes are usually regular, wheat-brewed soy sauce.

Our guide to reading labels for hidden gluten covers the wider set of words and rules.

Other condiments with hidden gluten

Soy sauce is only one place where gluten shows up unexpectedly in a kitchen. The following are worth checking, because some versions contain gluten and others do not.

Condiments and gluten
Condiment	Why it may contain gluten	What to do
Malt vinegar	Made from malted barley. Advice differs by country: some coeliac societies list it as suitable because the finished vinegar tests below the gluten-free threshold, while in other countries it cannot carry a gluten-free claim. Distilled, wine, cider and rice vinegars are usually considered gluten-free, but check labels.	Follow your national coeliac society's guidance, or use wine, cider or rice vinegar.
Stock cubes and bouillon	Some contain wheat flour, barley or gluten-containing flavourings.	Choose a cube labelled gluten-free, or make stock at home.
Miso	Some miso is made with barley (mugi miso) or contains other grains. Rice and soy miso is usually gluten-free.	Check the ingredient list for barley, wheat and rye.
Teriyaki and stir-fry sauces	Built on regular soy sauce, so usually contains wheat.	Choose a labelled gluten-free product or make your own with tamari.
Worcestershire sauce	Often contains malt vinegar. Some brands also contain anchovy, so it is not vegan.	Look for a gluten-free, vegan version.
Hoisin and oyster-style sauces	Often contain soy sauce or wheat flour, and oyster sauce contains shellfish.	Check the label for wheat.
Salad dressings and marinades	May use soy sauce, malt vinegar or wheat starch.	Read the ingredients every time.
Mustard and ketchup	Usually gluten-free, but some flavoured varieties are not.	Check, especially for malt vinegar.

Vegan and gluten-free labels are separate questions. Neither one tells you about the other, and a vegan sauce can easily contain wheat.

Cross-contact and coeliac disease

A bottle that has a wheat-containing sauce poured from it, or a spoon dipped in two sauces, can carry traces between them. Keep a separate gluten-free bottle where practical, and avoid sharing utensils. For coeliac disease, the right threshold and the right products are a matter for a clinician and your national coeliac society, whose advice should take priority over general guides such as this one.

What this guide is based on

That regular soy sauce is brewed from soybeans and wheat, that tamari is traditionally made with little or no wheat but is not guaranteed wheat-free, that malt vinegar is made from barley, and that some miso uses barley, is widely documented general food knowledge.
Product formulations differ by brand and country and change over time. No figures from our own testing are given, and no brand is named or rated. Check each label.
Which condiments to check is a general list, not a complete one. Gluten-free label rules differ by country.
Allergy and coeliac statements are general. Read labels and ask a coeliac society, doctor or dietitian about your own needs.