Is there gluten in clam chowder?

Gluten is a protein found in grains like wheat, barley, and rye. For people with celiac disease or gluten sensitivity, consuming gluten can cause digestive issues and other health problems. When preparing clam chowder, it’s important to know whether the ingredients contain gluten.

Quick Answer

Most traditional clam chowder recipes do not contain gluten. The main ingredients in clam chowder are clams, potatoes, onion, celery, broth or milk, and seasonings. None of these ingredients naturally contain gluten. However, clam chowder served in restaurants may be thickened with wheat flour or contaminated with gluten during preparation. People with celiac disease or gluten sensitivity should ask about how the chowder is prepared when dining out.

What is Clam Chowder?

Clam chowder is a thick, creamy soup that originated in New England. The main ingredients are chopped clams, diced potatoes, onions, and celery simmered in milk or clam broth. Common seasonings include salt, pepper, parsley, thyme, bay leaves, and paprika. There are several variations of clam chowder:

  • New England clam chowder – Creamy white chowder made with milk or cream.
  • Manhattan clam chowder – Tomato-based broth.
  • Rhode Island clam chowder – Clear broth with no cream.
  • Minorcan clam chowder – Spicy version with datil peppers.

While recipes can vary, traditional clam chowders do not contain any gluten-containing ingredients. The base is clams and potatoes thickened with cream or milk.

Do Clams Contain Gluten?

Clams are naturally gluten-free. Clams are mollusks that live in saltwater habitats. They do not contain any grains or gluten. Fresh, canned, or frozen clams can be safely eaten on a gluten-free diet as long as they haven’t been contaminated.

Potential Sources of Gluten in Clams

Although clams don’t naturally contain gluten, there are some potential sources of contamination:

  • Breading – Clams may be breaded before frying, which could contain gluten.
  • Marinades or Sauces – Many store-bought marinades, cocktail sauces, and tartar sauces contain gluten.
  • Shared Cooking Equipment – Clams cooked on shared grills or steamers may pick up traces of gluten from other foods.

When preparing clams at home, avoid any breading or sauce that could be a source of gluten. When ordering clams in restaurants, check that they are not breaded or cooked alongside breaded items.

Do Potatoes Contain Gluten?

Potatoes are a naturally gluten-free food. Potatoes are tubers that grow underground on potato plants. They do not contain grains or gluten. All types of potatoes, including russet, red, yellow, purple, fingerling, and sweet potatoes, are gluten-free.

Potatoes should be safe for gluten-free diets as long as they are not contaminated. Sources of potential gluten contamination include:

  • Coating: Potatoes may be coated in wheat-based batter before frying.
  • Shared Oil: French fries and hash browns can pick up traces of gluten in shared fryer oil.
  • Mashed: Instant potato flakes or powders sometimes contain gluten from additives.

When preparing potatoes at home, avoid any batter coating and make sure the oil has not been used to fry breaded items. When ordering potatoes in restaurants, request plain baked or ask how they are cooked.

Do Onions Contain Gluten?

Onions do not naturally contain gluten. Onions belong to the Amaryllidaceae plant family, which also includes other bulb vegetables like garlic, shallots, leeks, and chives. None of these allium vegetables contain grains or gluten.

All types of fresh, frozen, or dried onions are gluten-free and safe to eat on a gluten-free diet. This includes:

  • Yellow onions
  • White onions
  • Red onions
  • Shallots
  • Leeks
  • Chives
  • Green onions

The only potential source of gluten in onions would be cross-contamination during processing or cooking. But this is unlikely since onions are rarely combined with gluten-containing ingredients.

Do Celery and Other Vegetables Contain Gluten?

Fresh vegetables like celery, carrots, bell peppers, and other veggies do not naturally contain gluten. However, packaged pre-cut vegetables or frozen vegetable blends may be subject to cross-contamination:

  • Additives: Some pre-cut vegetable products contain anti-caking agents or seasonings that could contain gluten.
  • Shared Equipment: Frozen veggie blends are sometimes processed on equipment shared with wheat-based foods.

When preparing homemade clam chowder, it’s safest to use fresh vegetables that have been washed at home. If using any pre-cut or frozen vegetables, check the labels carefully for gluten-containing additives.

Does Milk or Cream Contain Gluten?

Plain dairy products like milk, cream, and butter do not naturally contain gluten and are safe for gluten-free diets. Problems arise when additives are introduced:

  • Flavored Milks: Chocolate or strawberry milk can contain thickeners and stabilizers with gluten.
  • Non-Dairy Milks: Almond, soy, oat, and rice milk are made from gluten-containing grains.
  • Additives: Some creamers and coffee whiteners contain wheat-based ingredients.

When making clam chowder at home, stick to plain dairy products like whole milk, heavy cream, or half-and-half. If using any flavored or non-dairy milks, read labels carefully and contact manufacturers if uncertain.

Do Broths Contain Gluten?

Plain broths and stocks made from meat, fish, or vegetables are naturally gluten-free. However, some commercial broths may contain gluten:

  • Hydrolyzed Wheat Protein: Found in many store-bought broths and stocks.
  • Miso Paste: Used in some Asian broths, miso is fermented soybean paste that contains gluten.
  • Shared Equipment: Some factories make wheat-based and gluten-free broths on shared lines.

When buying canned or boxed broths, read labels carefully to make sure they don’t list any wheat-based ingredients. Or make your own gluten-free seafood or clam broth at home.

Do Herbs and Spices Contain Gluten?

Most pure, dried herbs and spices do not contain gluten and are considered safe for gluten-free diets. These include:

  • Parsley
  • Thyme
  • Bay leaves
  • Pepper
  • Paprika
  • Red pepper flakes
  • Sea salt

However, some herbs and spice blends may contain gluten-based additives such as wheat flour, maltodextrin, or dextrin. Potential risky products include:

  • Spice blends
  • Seasoned salt
  • Chili powder
  • Curry powder

When making your own clam chowder, stick to single-ingredient dried herbs and spices. If using any blends or rubs, check that they are labeled gluten-free.

Thickeners Used in Clam Chowder

Some clam chowder recipes call for flour, cornstarch, or other thickening agents to give the broth more body and texture. Here are some potential thickeners:

Thickener Gluten-Free?
All-purpose flour No (contains wheat)
Cornstarch Yes
Arrowroot starch Yes
Potato starch Yes
Tapioca flour Yes

Traditional clam chowder recipes rely on cream or milk to thicken the broth without added starches or flour. But some modern recipes call for corn starch or other gluten-free starches to stabilize and thicken the soup. Avoid wheat-based flours to keep clam chowder gluten-free.

Is Clam Chowder Gluten-Free at Restaurants?

Ordering clam chowder at restaurants tends to be riskier than preparing it yourself at home. While the base ingredients may be gluten-free, restaurant prep introduces opportunities for cross-contamination. Potential sources of gluten include:

  • Thickeners – Restaurants may add wheat flour to thicken chowder.
  • Breading – Clams or potatoes may be breaded before frying.
  • Shared Fryers – Fries may be cooked in oil used for breaded foods.
  • Shared Equipment – Chowder may be ladled with spoons used for wheat-based dishes.
  • Cross-Contact – Clam chowder is often prepared in close proximity to flour-thickened soups.

The safest option is to visit dedicated gluten-free restaurants that avoid all cross-contact issues. At regular restaurants, ask detailed questions about preparation and ingredients before ordering. Some tips include:

  • Ask if the chowder contains wheat flour as a thickener
  • Request no bread bowls, croutons, or crackers on top
  • Ask if fried clams or potatoes are breaded
  • Request a “clean” spoon if concerned about cross-contact

With vigilance, those with celiac disease or gluten sensitivity can often enjoy clam chowder from restaurants. Butcommunicating with staff is key.

Should Clam Chowder Be Thickened?

Adding flour or starch to thicken clam chowder is optional. Some argue that the rich, creamy base of milk or cream is already sufficiently thick. Potential issues with adding thickeners include:

  • Difficulty finding gluten-free option
  • Changes mouthfeel and texture
  • Dulls flavor of the clams and potatoes
  • Not traditional in many recipes

Many traditional clam chowder enthusiasts argue the soup should be thickened only with plenty of potatoes and cream. This also makes it easier to keep gluten-free. But light thickening with cornstarch or arrowroot can help stabilize broth without significantly altering texture.

Gluten-Free Clam Chowder Recipe

Here is a basic gluten-free clam chowder recipe:


  • 3 tablespoons butter
  • 1 large onion, diced
  • 3 ribs celery, sliced
  • 2 medium russet potatoes, peeled and diced
  • 2 (6.5 ounce) cans chopped clams
  • 1 cup seafood or vegetable broth
  • 1 cup heavy cream
  • 2 bay leaves
  • 1 teaspoon dried thyme
  • Salt and pepper to taste


  1. In large pot, melt butter over medium heat. Add onions and celery and cook 5 minutes until softened.
  2. Add potatoes and cook 3 minutes, stirring frequently.
  3. Pour in clams with their juice, broth, heavy cream, bay leaves, thyme, salt, and pepper. Bring to a boil.
  4. Reduce heat and simmer 20 minutes until potatoes are tender.
  5. Remove bay leaves. Use immersion blender to slightly thicken chowder.
  6. Taste and adjust seasoning as needed. Garnish with parsley.

This simple clam chowder recipe avoids potential sources of gluten like wheat flour and shared fryers. Choose canned clams packed in water without additives, and make sure the broth is gluten-free. With these basic precautions, you can safely enjoy homemade clam chowder on a gluten-free diet.


Traditional clam chowder recipes are naturally gluten-free, relying on simple ingredients like clams, potatoes, onions, and cream. When cooked at home from scratch, clam chowder is generally safe for those avoiding gluten. The biggest risks come from restaurant preparations, where cross-contamination is common. By asking questions and being selective when dining out, people with celiac disease and gluten intolerance can often enjoy clam chowder without issues. With proper precautions to avoid wheat-based thickeners and cross-contact, clam chowder can be a delicious gluten-free comfort food.

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