Can soup have gluten? What you need to know

December 24, 2025 •

3 min read

For individuals with celiac disease or a gluten sensitivity, many pre-made and restaurant soups are a major source of hidden gluten, as companies commonly use wheat or wheat-based products as a thickening agent. This can make enjoying a simple, comforting bowl of soup surprisingly challenging and risky.

Quick Summary

Soup is not always a gluten-free meal due to common additives like wheat-based thickeners, flavor enhancers, and certain grains such as barley. Always scrutinize product labels on store-bought versions and exercise caution regarding potential cross-contamination when dining out or using shared kitchen spaces.

Key Points

Thickeners and Flavorings: Many soups use wheat flour, yeast extract, or malt-based flavorings that contain gluten.
Canned Soups are Risky: Many brands use wheat flour to thicken creamy or condensed soups, so always check labels.
Broth and Bouillon: Pre-packaged broths, stocks, and bouillon cubes can contain hidden gluten sources, so certified gluten-free options are essential.
Cross-Contamination is a Concern: Restaurant soups, especially those from a buffet or prepared in shared equipment, pose a high risk of cross-contamination.
Homemade is the Safest Option: Making soup from scratch gives you complete control over every ingredient and preparation step.
Not all Soups with Grains are Safe: Even if a soup contains rice or corn, it could still be contaminated if it is processed or cooked in facilities that also handle gluten.

Common Sources of Gluten in Soup

While a basic, homemade soup with fresh vegetables, meat, and a simple stock should be naturally gluten-free, several ingredients in commercial or restaurant soups can introduce gluten. The key is to be aware of these common additions and to scrutinize labels and ingredient lists carefully.

Thickeners and Roux

Many creamy soups, bisques, and chowders achieve their thick consistency with a roux, which is a combination of flour and fat.

Cream-based soups like clam chowder, broccoli cheddar, and cream of mushroom often contain wheat flour.
Chowders and stews may use flour to give them body.
Gravies and pan sauces added to meat-based soups can also use flour as a thickener.

Broths, Stocks, and Bouillons

For convenience, many cooks and food manufacturers use pre-made broths, stocks, or bouillon cubes, which can contain gluten.

Yeast Extract: Often used for flavor enhancement, this ingredient may be derived from barley and is not always gluten-free unless specifically labeled.
Natural Flavors: The source of “natural flavors” can sometimes be a gluten-containing grain like barley. Unless a product is certified gluten-free, these flavors are a risk.
Seasoning Mixes: Some spice blends contain anti-caking agents or stabilizers derived from wheat flour.

Grains, Pastas, and Additions

Certain ingredients added to soups are obvious gluten sources and should be avoided unless a certified gluten-free alternative is used.

Barley and couscous are often added to hearty soups and stews.
Regular pasta noodles are a very common addition, especially in chicken noodle soup.
Bread crumbs, croutons, or biscuits served with soup are potential sources of gluten.

Cross-Contamination

This is a major concern, particularly when dining out or consuming food prepared in shared kitchens.

Shared Surfaces: A restaurant kitchen may use the same cutting boards, utensils, or pots for gluten-free and gluten-containing ingredients.
Frying Oils: If a restaurant fries gluten-free items in the same oil as breaded items, the oil becomes cross-contaminated.
Communal Serving: A shared ladle or buffet line can easily transfer gluten into a soup that would otherwise be safe.

Homemade vs. Store-Bought Soup: A Comparison


Feature	Homemade Soup	Store-Bought Soup
Ingredients	Complete control; can ensure every ingredient is gluten-free.	Many potential hidden sources in thickeners, broths, and flavorings.
Cross-Contamination	Easily preventable with dedicated equipment and careful food preparation.	High risk, especially in kitchens that also prepare gluten-containing items.
Labeling	N/A	Requires careful reading; look for "certified gluten-free" labels, as ingredients can change.
Flavoring	Custom seasoning with pure herbs and spices.	Watch for "natural flavors" and yeast extract, which can contain gluten.
Thickening	Use safe alternatives like rice flour, cornstarch, pureed vegetables, or potato starch.	Frequently uses wheat flour as a thickener, especially in condensed and creamy soups.

How to Enjoy Gluten-Free Soup Safely

For the Home Cook

Use Certified Gluten-Free Broth: When buying pre-packaged broth, look for a certified gluten-free label. Brands like Swanson offer gluten-free stock options. Better yet, make your own broth from scratch to be 100% certain of the ingredients.
Thicken Wisely: Use alternatives to wheat flour, such as cornstarch, arrowroot powder, or a puree of beans or vegetables. Ensure these thickeners are certified gluten-free to avoid cross-contamination.
Check Every Ingredient: Even seemingly safe additions like rice or legumes can be cross-contaminated during processing. Only use products from trusted gluten-free brands.

For the Restaurant Diner

Ask Specific Questions: Don't just ask, "Is this gluten-free?" Inquire about specific ingredients and preparation methods. Ask if flour is used as a thickener or if the soup is prepared in a separate pot.
Beware of Soup of the Day: Daily specials or house-made soups often change and may not be made with gluten-free protocols. Order from the permanent menu, where ingredients are more consistent.
Identify Safe Options: Clear, broth-based soups without noodles or grains are generally safer, but still require inquiry about the stock and seasoning blends.

Conclusion

In short, while naturally prepared soups can be entirely gluten-free, the reality is that many convenience and restaurant soups contain hidden gluten. Common culprits include wheat flour used as a thickener, gluten-containing broths or flavor enhancers, and the risk of cross-contamination. By understanding these risks, carefully reading labels, and making informed choices, those with gluten sensitivities can continue to enjoy delicious and safe soup. For the most peace of mind, homemade soup made with certified gluten-free ingredients is the best option.

Learn more about safe gluten-free living from the Celiac Disease Foundation(https://celiac.org/gluten-free-living/gluten-free-foods/).

Frequently Asked Questions

You should always exercise caution. While a restaurant may claim a soup is gluten-free, it could still be cross-contaminated from shared equipment, utensils, or oil. Always ask detailed questions about ingredients and preparation methods.

Classic tomato soup recipes are naturally gluten-free, but many canned and pre-made versions often add wheat flour as a thickener. It is crucial to read the ingredient label carefully, as gluten can be a hidden ingredient.

No, many brands now offer specific lines of certified gluten-free canned soups. You can find these by looking for a 'certified gluten-free' label on the packaging. However, traditional recipes from those same brands often contain gluten.

Safe gluten-free thickeners include cornstarch, arrowroot powder, rice flour, potato starch, or pureeing some of the vegetables or beans in the soup itself.

Not all, but many contain hidden gluten sources like yeast extract or flavorings derived from barley. It is safest to buy products explicitly labeled as 'certified gluten-free' or to make your own stock.

Yeast extract is a common flavor enhancer that can be derived from various sources. If it is made from barley, it will contain gluten. Always check for a 'certified gluten-free' label when yeast extract is listed as an ingredient.

Yes, even if all ingredients in a soup are gluten-free, cross-contamination is a significant risk. Using shared utensils, cutting boards, or cooking surfaces can introduce traces of gluten that are harmful to those with celiac disease.