Yes, classic mayonnaise is gluten free: it contains no gluten. Oil, egg yolk, mustard, vinegar or lemon, salt: there’s no cereal in the recipe. Gluten can, however, slip into an industrial mayonnaise, a light version or a derived sauce, through a starch, a thickener or malt vinegar.

Why mayonnaise is gluten free

Mayonnaise is an emulsion: you whisk an egg yolk with mustard, then add the oil drop by drop, and season with vinegar or lemon and salt. None of these ingredients naturally contains gluten.

Two of them deserve a word:

  • Mustard. A classic Dijon mustard contains no gluten-containing cereal; some mustard specialities, on the other hand, add wheat flour or malt vinegar. We covered this in detail in our article on stocks and condiments.
  • Vinegar. Spirit vinegar, wine vinegar and cider vinegar are gluten free. Malt vinegar, made from barley and not distilled, is not, and it’s common in the United Kingdom. We’ve given it its own article.

Homemade mayonnaise made with Dijon mustard and wine vinegar or lemon therefore raises no questions.

What’s still at risk

Industrial mayonnaises. Mayonnaise in a jar or a squeezy bottle is a factory recipe that has to last months without separating. You’ll often find water, sugar, flavourings, modified starch and thickeners. The starch can come from corn, potato or wheat; if it comes from wheat, the European label must highlight it. Most shop-bought mayonnaises have no gluten-containing cereal in their list, but the recipe changes from brand to brand and country to country.

Malt vinegar. On a British mayonnaise or an imported sauce, “malt vinegar” or “malt vinegar (barley)” signals barley. As a precaution, avoid it unless it carries a “gluten free” label.

Light versions. Less oil means more water, and therefore more thickeners and starch to hold the texture. They don’t all contain gluten, far from it, but they’re the ones that need the most careful reading.

Derived sauces. Tartare, cocktail, shop-bought aioli, burger sauce, andalouse, samurai sauce, kebab garlic sauce: mayonnaise is just a base, to which gherkins, ketchup, spices, flavourings and thickeners are added. Some recipes contain Worcestershire sauce, whose malt vinegar comes from barley. Each sauce needs reading as a product in its own right.

The opened jar and restaurants. A spoon that has touched toast or a burger bun leaves crumbs in the jar. In restaurants, homemade mayonnaise is generally safe; the problem is the shared ramekin and the brush used to coat the buns. The habits that prevent this at home are in our article on cross-contamination.

The table

No risk To check Often contains gluten
Homemade mayonnaise (Dijon mustard, wine vinegar or lemon) Mayonnaise in a jar or squeezy bottle Sauces made with barley malt vinegar
Mayonnaise labelled “gluten free” Light mayonnaises Derived sauces with Worcestershire sauce
Homemade aioli (garlic, oil, egg yolk) Tartare, cocktail, burger, andalouse sauces Jar opened with a spoon used on toast
Kebab garlic sauce, restaurant sauces

How to choose

  • Read the ingredients list. In Europe, cereals containing gluten are among the allergens that must be declared, highlighted in bold or capitals. “WHEAT starch” or “malt vinegar (BARLEY)” can be spotted in seconds. A “modified starch” with no further detail isn’t wheat: if it were, wheat would be named.
  • Look for the “gluten free” label. Governed by Commission Implementing Regulation (EU) No 828/2014, it guarantees no more than 20 mg/kg of gluten, traces included.
  • The Crossed Grain symbol adds checks by a coeliac association, under licence.
  • A “may contain gluten” warning without a “gluten free” label signals a risk that nothing measures: if you’re coeliac, choose another jar.

For the rest of the method, our guide to reading labels explains each statement.

In the kitchen

Mayonnaise is one of the easiest sauces to make yourself, and the homemade version settles every question at once. It also goes with other store-cupboard basics that have their own traps: butter, gluten free but quickly contaminated, and baking powder, whose starch carrier can be wheat.

In short

  • Classic mayonnaise contains no gluten: oil, egg, mustard, vinegar or lemon, salt.
  • In jars, most contain none, but the starch and the vinegar need checking.
  • Malt vinegar, common in the United Kingdom, comes from barley.
  • Light versions and derived sauces each need reading as a product in their own right.
  • In restaurants, homemade mayonnaise is generally safe; the shared ramekin, less so.

This information is no substitute for medical advice. Industrial recipes change without warning: the label on the jar in your hand is what counts.