The quick answer: which soy sauces are gluten-free?
| Product | Usually contains wheat? | Gluten-free? |
|---|---|---|
| Conventional Japanese soy sauce (shoyu) | Often | Do not assume |
| Tamari | Sometimes, but often made without wheat | Check for a gluten-free declaration |
| Specifically labelled gluten-free soy sauce | Formulation varies | Must meet applicable gluten-free requirements |
| Low-salt soy sauce | Often | Not automatically |
| Dark soy sauce | Often | Not automatically |
| Light soy sauce | Often | Not automatically |
| Sweet soy sauce (kecap manis) | May contain wheat | Check the product |
| Teriyaki sauce | Often contains soy sauce | Not automatically |
| Coconut aminos | Usually made without wheat | Check the actual formulation and label |
| Liquid aminos | Varies by product | Check the label |
Soy sauce
Often contains wheat. Check gluten and soy.
Tamari
Often made without wheat. Verify gluten-free status.
Gluten-free soy sauce
Meets gluten-free claim rules. May still contain soy.
Gluten-free is not soy-free. A gluten-free soy sauce or tamari usually still contains soy.
Important: A sauce being wheat-free does not, by itself, guarantee it is gluten-free. Barley, rye, cross-contact and the finished product's gluten content may also matter.
1. Why does soy sauce contain wheat?
Traditional soy sauce is commonly made by fermenting soybeans and wheat with salt, water and microorganisms.
The ingredients and production methods vary by style and manufacturer.
What does wheat do in soy sauce?
Wheat contributes carbohydrates that can be broken down during fermentation and help develop flavour and aroma.
It plays a role in the characteristic taste of many traditional soy sauces.
Is soy sauce mainly made from soybeans?
Soybeans are a central ingredient, but that does not mean wheat is absent.
Some varieties contain substantial proportions of wheat in their starting ingredients.
Does wheat in soy sauce mean it contains gluten?
Wheat naturally contains gluten proteins.
Processing and fermentation alter those proteins, but this does not automatically establish that the finished sauce is suitable for someone with coeliac disease.
What should you look for?
Check for wheat in the ingredients and look for a reliable gluten-free declaration where appropriate.
2. Is ordinary soy sauce gluten-free?
Do not assume it is.
Many conventional soy sauces contain wheat.
Example ingredients
Soy sauce (simplified)
Ingredients: Water, soybeans (soy), wheat, salt.
This is a typical simplified ingredient example.
What about supermarket own-brand soy sauce?
Recipes vary.
Some products contain wheat, while others may be specifically formulated and labelled gluten-free.
What about well-known brands?
Do not assume every product from a brand uses the same recipe.
A manufacturer may sell ordinary soy sauce, reduced-salt soy sauce, tamari and a separate gluten-free version.
Is the front label enough?
No.
Read the full ingredients list and check the gluten-free claim.
For coeliac disease, the suitability of the finished product matters.
3. What is tamari?
Tamari is a Japanese-style soy sauce traditionally associated with miso production.
It is often made with little or no wheat, but recipes vary.
Is tamari naturally gluten-free?
Not always.
Many tamari products are made without wheat, but some may contain wheat or be affected by gluten cross-contact.
Why do people recommend tamari for gluten-free cooking?
Because wheat-free tamari is widely available and can be used in many recipes that would otherwise call for ordinary soy sauce.
Is every bottle labelled tamari suitable for coeliac disease?
No.
Choose a product with appropriate gluten-free information.
Does tamari taste the same as soy sauce?
Tamari often has a rich, savoury flavour and may taste different from conventional shoyu.
The exact flavour depends on the ingredients and fermentation process.
4. Soy sauce versus tamari: what's the difference?
| Feature | Conventional soy sauce | Tamari |
|---|---|---|
| Main ingredient | Soybeans | Soybeans |
| Wheat | Commonly used | Often absent or used in smaller amounts |
| Fermentation | Usually fermented | Usually fermented |
| Taste | Salty, savoury, aromatic | Often rich and savoury |
| Gluten-free by default? | No | No |
| Suitable for soy allergy? | No, if soy-derived | No, if soy-derived |
| Best approach for coeliac disease | Choose an appropriately labelled gluten-free version | Choose an appropriately labelled gluten-free version |
Can you substitute tamari for soy sauce?
Often, yes.
Tamari can work in:
- Stir-fries
- Marinades
- Dipping sauces
- Dressings
- Rice dishes
- Noodle dishes
However, flavour and salt content can differ, so adjust recipes as needed.
5. Does fermentation remove gluten from soy sauce?
Fermentation breaks down many components of the starting ingredients, including proteins.
However, the fact that a sauce has been fermented does not prove that it is gluten-free.
Why is this complicated?
Gluten proteins can be broken into smaller fragments during fermentation or hydrolysis.
This can make gluten analysis in fermented products more technically challenging than testing an ordinary solid food.
Does fermentation destroy every clinically relevant gluten fragment?
You should not assume so.
Can someone with coeliac disease eat ordinary soy sauce because it has been fermented?
Do not rely on that assumption.
Follow appropriate coeliac guidance and choose products whose gluten-free status has been established.
What about online claims that fermentation makes soy sauce safe?
Treat broad claims cautiously.
The original ingredients, processing, testing methods and finished product all matter.
Fermented does not automatically mean gluten-free.
6. What does gluten-free mean on a UK soy sauce label?
In the UK, a product labelled gluten-free must contain no more than 20 parts per million of gluten.
This is the regulated threshold for the claim.
Does gluten-free mean absolutely zero gluten?
No.
It means the product meets the applicable limit.
Does a gluten-free label matter more than simply seeing no wheat in the ingredients?
For someone with coeliac disease, a reliable gluten-free declaration provides additional information about the finished product.
An ingredient list alone cannot measure gluten concentration.
Can a product contain a wheat-derived ingredient and still be labelled gluten-free?
In some circumstances, yes, if the product meets the relevant requirements.
However, that does not automatically make it suitable for someone with a wheat allergy.
Is wheat-free the same as gluten-free?
No.
Wheat-free products may contain other gluten-containing cereals or be affected by cross-contact.
Read our guide to gluten-free versus wheat-free.
7. What about wheat allergy?
Wheat allergy and coeliac disease are different conditions.
Coeliac disease
An autoimmune condition triggered by gluten.
Wheat allergy
An immune reaction to particular proteins in wheat.
Can a gluten-free soy sauce contain wheat-derived ingredients?
It is possible for gluten-free foods to contain certain specially processed wheat-derived ingredients.
Does that make them suitable for wheat allergy?
Not automatically.
A person with wheat allergy must follow their individual allergy-management guidance.
Can tamari contain soy?
Yes.
Most traditional tamari is soy-derived.
Someone with soy allergy should not assume that switching from soy sauce to tamari solves the problem.
Read our wheat allergy versus coeliac disease guide.
8. Is dark soy sauce gluten-free?
Not automatically.
Dark soy sauce is commonly used for colour, flavour and depth in cooking.
Some varieties include wheat.
Is dark soy sauce sweeter?
Some products contain added sugar or other ingredients, but recipes vary.
Can dark soy sauce be gluten-free?
Yes, gluten-free versions may be available.
What should you check?
Look at the specific product rather than relying on the words dark soy sauce.
9. Is light soy sauce gluten-free?
Not automatically.
Light soy sauce generally refers to a style of soy sauce, not a gluten-free formulation.
Does light mean reduced salt?
No.
Light soy sauce and reduced-salt soy sauce are not necessarily the same thing.
Does light mean less gluten?
No.
The name does not establish gluten content.
What about Chinese light soy sauce?
Many conventional versions contain wheat.
Check the ingredients and gluten-free information.
10. Is low-salt soy sauce gluten-free?
Not automatically.
Reduced-salt or low-salt soy sauce is formulated to contain less salt than a comparison product.
It does not necessarily contain less gluten.
Can reduced-salt soy sauce contain wheat?
Yes.
Can gluten-free soy sauce be reduced-salt?
Yes, some products offer both features.
What should you look for?
Separate the two claims:
- Reduced salt concerns sodium or salt content.
- Gluten-free concerns gluten content.
One does not establish the other.
11. Is sweet soy sauce gluten-free?
Sweet soy sauce, including kecap manis, is commonly used in Indonesian cooking.
It usually contains sweetening ingredients and soy sauce or fermented soybean ingredients.
Can kecap manis contain wheat?
Yes.
Is every kecap manis gluten-free?
No.
What about homemade sweet soy sauce?
Its suitability depends on the soy sauce and other ingredients used.
Can you make a gluten-free version?
Yes.
Use an appropriately labelled gluten-free soy sauce or tamari and check the remaining ingredients.
12. Is teriyaki sauce gluten-free?
Not automatically.
Teriyaki sauce often contains soy sauce.
If that soy sauce contains wheat, the teriyaki sauce may contain gluten.
Other ingredients may include
- Sugar
- Mirin
- Sake
- Ginger
- Garlic
- Starches
- Flavourings
Does homemade teriyaki sauce contain gluten?
That depends on the ingredients.
Is bottled teriyaki sauce gluten-free?
Some are specifically labelled gluten-free.
Others are not.
What about restaurant teriyaki?
Ask about the actual sauce and how the dish is prepared.
Do not assume a dish is gluten-free because it contains rice and vegetables.
13. Is oyster sauce gluten-free?
Not automatically.
Oyster sauce is a savoury sauce used in many Asian dishes.
Some formulations contain wheat-derived ingredients.
Is oyster sauce the same as soy sauce?
No.
They are different sauces.
Can oyster sauce contain soy?
Yes, depending on the formulation.
Can oyster sauce be gluten-free?
Yes, gluten-free versions are available.
What should you check?
Read the ingredients and gluten-free declaration.
Someone with shellfish allergy must also consider the oyster ingredient independently of gluten.
14. Is hoisin sauce gluten-free?
Not automatically.
Hoisin sauce is a thick, sweet and savoury sauce.
Formulations vary and may contain wheat or other gluten-containing ingredients.
Is hoisin always made with wheat?
No.
Is it safe to assume hoisin is gluten-free?
No.
Can hoisin contain soy?
Yes.
What about restaurant hoisin sauce?
Ask the restaurant to confirm the ingredients and cross-contact arrangements.
15. Is fish sauce gluten-free?
Many fish sauces are made from fish, salt and water, and may be naturally gluten-free.
However, not every product has the same formulation.
Can fish sauce contain added ingredients?
Yes.
Some products contain sugar, flavourings or other additions.
Is fish sauce a substitute for soy sauce?
It can provide savoury flavour, but it tastes different.
Is fish sauce suitable for fish allergy?
No, not where the fish ingredient is relevant to the individual's allergy.
Is every fish sauce gluten-free?
Do not assume so.
Check the actual product.
16. What about coconut aminos?
Coconut aminos is a savoury seasoning generally made using coconut-derived sap and salt.
It is often used as an alternative to soy sauce.
Does coconut aminos contain soy?
Many formulations do not contain soy as a deliberate ingredient.
However, check the complete product label.
Does coconut aminos contain wheat?
It is often formulated without wheat, but this should not be assumed for every product.
Is coconut aminos gluten-free?
Some products are labelled gluten-free.
Choose an appropriately labelled product when managing coeliac disease.
Does coconut aminos taste like soy sauce?
It is usually milder and sweeter.
Is coconut aminos safe for coconut allergy?
Not automatically.
The coconut origin is relevant to anyone with a diagnosed coconut allergy.
Read our guide to coconut and nut allergies.
17. What are liquid aminos?
Liquid aminos are savoury seasonings made from protein-derived amino acids.
The source ingredients vary.
Can liquid aminos be soy-derived?
Yes.
Can liquid aminos be coconut-derived?
Yes, depending on the product.
Are all liquid aminos gluten-free?
No universal conclusion can be made.
Are liquid aminos suitable for soy allergy?
Not automatically.
What should you check?
Identify the protein source and read the full ingredient declaration.
18. Five practical ingredient-label examples
These are fictional examples to demonstrate how different sauces should be interpreted.
Example 1: Conventional soy sauce
Conventional soy sauce
Ingredients: Water, soybeans (soy), wheat, salt.
What matters: Wheat is deliberately included.
Do not assume this product is suitable for coeliac disease.
Example 2: Gluten-free tamari
Gluten-free tamari
Ingredients: Water, soybeans (soy), salt.
Front label: Gluten-free.
What matters: The gluten-free declaration is important for coeliac disease. The product still contains soy.
Example 3: Reduced-salt soy sauce
Reduced-salt soy sauce
Ingredients: Water, soybeans (soy), wheat, salt.
Front label: Reduced salt.
What matters: Reduced salt does not mean gluten-free.
Example 4: Teriyaki marinade
Teriyaki marinade
Ingredients: Sugar, water, soy sauce (soybeans (soy), wheat, salt), ginger, garlic.
What matters: Wheat is present through the soy sauce ingredient.
Example 5: Coconut aminos
Coconut aminos
Ingredients: Coconut sap, sea salt.
Front label: Gluten-free.
What matters: The formulation does not declare wheat or soy, and the gluten-free claim provides relevant information. Coconut remains relevant to anyone avoiding coconut.
19. How to read soy sauce labels in the UK
Step 1: Check the product name
Identify whether it is soy sauce, tamari, teriyaki, hoisin or another sauce.
Step 2: Read the complete ingredients list
Look for wheat, barley, rye and other gluten-containing cereals.
Step 3: Check the gluten-free declaration
For coeliac disease, a reliable gluten-free claim is particularly useful.
Step 4: Check soy separately
A gluten-free soy sauce may still contain soy.
Step 5: Review precautionary information
Check any statements about possible cross-contact.
Step 6: Consider other allergies
Some sauces contain sesame, fish, shellfish or other allergens.
Step 7: Check the current packaging
Manufacturers may reformulate products.
Step 8: Don't rely on the colour of the sauce
Dark, light and reduced-salt descriptions do not establish gluten-free status.
Read our guide to checking food labels.
20. What about soy sauce in restaurants?
Restaurant meals require additional care.
Soy sauce can appear in dishes that do not obviously look wheat-based.
Examples include
- Stir-fries
- Fried rice
- Noodle dishes
- Sushi accompaniments
- Marinades
- Glazes
- Dipping sauces
- Meat and vegetable dishes
- Broths
- Dressings
Does fried rice contain gluten?
Plain rice is naturally gluten-free.
However, fried rice may contain ordinary soy sauce or other gluten-containing ingredients.
Is sushi gluten-free?
Not automatically.
Rice and fish may be naturally gluten-free, but soy sauce, marinades, imitation crab, coatings and preparation practices may matter.
Are rice noodles gluten-free?
Plain rice noodles may be suitable, but sauces and preparation arrangements still need checking.
What should you ask the restaurant?
Ask whether the dish is suitable for someone with coeliac disease and whether gluten-free soy sauce or tamari is used.
Also ask about cross-contact, shared equipment and preparation surfaces.
What about takeaway food?
Ask the business directly about the ingredients and preparation.
Do not assume a dish is gluten-free simply because it does not contain bread or pasta.
21. Cross-contact when cooking with soy sauce
Even if you use gluten-free soy sauce at home, other sources of gluten may be present.
Common examples
- A shared bottle with food residue around the opening
- Shared utensils
- Sauces mixed in the same container
- Marinades prepared with ordinary soy sauce
- Shared cooking surfaces
- Noodles cooked with wheat noodles
- Previously used frying equipment
Can a tiny amount of ordinary soy sauce matter for coeliac disease?
Gluten exposure matters for coeliac disease, including when symptoms are not obvious.
Do not assume a small splash of ordinary soy sauce is harmless.
What if someone accidentally uses ordinary soy sauce?
Follow their individual medical advice and coeliac-management guidance.
Does heating soy sauce remove gluten?
No.
Ordinary cooking does not reliably make a gluten-containing sauce gluten-free.
22. Can soy sauce ingredients change?
Yes.
Manufacturers can change recipes, suppliers or production methods.
A previously suitable product may be reformulated.
Does the barcode always change?
Not every formulation change requires a new barcode.
Significant changes, particularly those affecting declared allergens, may require a new product identifier under GS1 standards.
Can an app database contain an older ingredient list?
Yes.
A stored product record may not immediately reflect the formulation printed on a particular package.
Why check the actual label?
Because the current ingredients declaration is the information supplied with the product you're buying.
However, a label can also contain errors, and a photograph cannot detect undeclared allergens.
Read our guide to recipe changes and barcodes.
23. Gluten-free alternatives to ordinary soy sauce
Several alternatives may be suitable, depending on the person's dietary requirements.
| Alternative | Potential advantage | What to check |
|---|---|---|
| Gluten-free tamari | Similar savoury flavour | Gluten-free claim and soy allergy |
| Gluten-free soy sauce | Familiar flavour | Gluten-free declaration and other allergens |
| Coconut aminos | Often soy-free and wheat-free | Coconut, added ingredients and gluten-free claim |
| Gluten-free teriyaki sauce | Convenient for marinades | Complete ingredients and gluten-free claim |
| Suitable fish sauce | Strong savoury flavour | Fish allergy, formulation and gluten-free status |
| Homemade sauce | Greater ingredient control | Every ingredient and cross-contact |
Which tastes most like ordinary soy sauce?
Gluten-free tamari or a specifically formulated gluten-free soy sauce is often the closest substitute.
Which is best for soy allergy?
Soy-free alternatives may be more appropriate, but they must still be checked against the person's other allergies.
Which is best for coeliac disease?
Choose a suitable product with reliable gluten-free information.
24. A practical gluten-free stir-fry checklist
Before cooking:
- Check the soy sauce or tamari
- Confirm its gluten-free declaration
- Check the noodles or rice
- Check stock and seasoning mixes
- Check marinades
- Check other sauces
- Review relevant allergen information
- Use clean utensils and preparation surfaces
- Avoid shared gluten-containing ingredients
- Check every family member's additional restrictions
Simple meal idea
Try a stir-fry made with:
- Plain chicken or tofu, where suitable
- Fresh vegetables
- Rice or suitable gluten-free noodles
- Gluten-free tamari
- Garlic
- Ginger
- A suitable cooking oil
Check the full ingredients and individual dietary requirements.
A recipe using gluten-free tamari is not automatically free from soy, sesame or other allergens.
Always check the current product label before you buy: ingredients, allergen information and any free-from claim.
25. How ClearaScan helps with soy sauce ingredient checking
ClearaScan reads photographs of ingredient labels and checks recognised text against personalised Ingredient Guard rules.
Check wheat and gluten-related ingredients
When gluten is on your Ingredient Guard, ClearaScan flags wheat, barley, rye and other gluten-containing cereals wherever they're named, including inside a compound ingredient such as soy sauce (soybeans, wheat, salt).
It doesn't flag the words soy sauce, teriyaki or hoisin on their own for gluten. If a label names a sauce without listing what's in it, check that sauce yourself. A gluten-free claim on the pack isn't counted as a gluten match, and ClearaScan can't verify it.
Check soy separately
Someone with coeliac disease may be able to eat soy.
Someone with soy allergy may need to avoid soy sauce and tamari even when they are gluten-free.
When soy is on an Ingredient Guard, ClearaScan flags soy sauce, tamari and shoyu as soy, including gluten-free versions. 'May contain' statements are shown separately from ingredients that are deliberately included.
Check multiple family profiles
One family member may need to avoid gluten-containing ingredients.
Another may have soy allergy.
A third may need to avoid sesame or another ingredient.
Choose who the scan is for, then use Also check for... on the result to check the same label for someone else without photographing it again.
Read the actual label
ClearaScan works with recognised ingredient information on the product's packaging rather than relying solely on a barcode database record.
Important limitations
ClearaScan cannot:
- Measure gluten concentration
- Verify the 20 ppm threshold
- Determine whether fermentation has made a sauce suitable for coeliac disease
- Verify gluten-free certification
- Detect undeclared gluten
- Assess restaurant cross-contact
- Guarantee every ingredient has been recognised
- Determine individual clinical safety
A scan can help identify relevant ingredients, but it cannot establish that a sauce is gluten-free or suitable for someone with coeliac disease.
Always check the original label and follow appropriate medical and dietary guidance.
