Is Baking Powder Gluten Free? Not Always — Here's Why

Not always: baking powder can contain gluten. Its active ingredients, a bicarbonate and an acid, contain none, but they’re mixed with a starch that acts as a carrier, and that starch is sometimes wheat. Baking soda on its own, however, is gluten free.

Why the question arises

Baking powder isn’t a yeast: it’s a mixture of three things.

• A base, almost always sodium bicarbonate (“sodium carbonates” on the label).
• An acid, often a diphosphate or tartaric acid, which reacts with the base on contact with water and heat to release the carbon dioxide that makes the batter rise.
• A carrier, a starch that absorbs moisture, stops the reaction from starting in the sachet and makes measuring easier.

Neither the base nor the acid contains gluten. It all comes down to the carrier: depending on the country and the manufacturer, it’s corn, potato or rice starch… or wheat starch. In France, supermarkets sell baking powders whose carrier is wheat starch, next to others made with corn starch. The two look exactly alike.

What’s still at risk

Baking powder made with wheat starch. It contains gluten. The amount in a cake is small, but for a coeliac person, a gluten-free recipe has no reason to accept an ingredient containing gluten: leave it out.

Ready-made mixes. Self-raising flour, cake mixes, crêpe or pancake mixes: the raising agent is mixed into the flour, usually wheat flour. Only versions labelled “gluten free” are suitable.

Vocabulary mix-ups. In French, the word “levure” covers three very different products, and translations of recipes often blur them:

Brewer’s yeast has its own article: it can retain barley residues. And watch out for sourdough starter, which isn’t a yeast in a sachet but a fermented mixture of flour and water: made with wheat or rye flour, it contains gluten.

Baking soda and cream of tartar, on the other hand, are gluten free. Baking soda is a mineral salt; cream of tartar, a deposit from wine fermentation. Combined, they make a homemade baking powder.

The table

No risk	To check	Often contains gluten
Pure baking soda	Baking powder without a “gluten free” label	Baking powder made with wheat starch
Cream of tartar	Brewer’s yeast (flakes, supplements)	Self-raising flour
Fresh or dried baker’s yeast	Baking powders bought abroad	Cake, crêpe and pancake mixes
Baking powder labelled “gluten free”		Wheat or rye sourdough starter

How to choose

• Read the carrier. In Europe, cereals containing gluten are among the allergens that must be declared, highlighted in bold or capitals: “WHEAT starch” stands out. A corn or potato starch with no other cereal highlighted and no “may contain” raises no recipe question.
• Look for the “gluten free” label. Governed by Commission Implementing Regulation (EU) No 828/2014, it commits the manufacturer to no more than 20 mg/kg of gluten, traces included. Many baking powders carry it, and it’s the simplest choice.
• The Crossed Grain symbol adds checks by a coeliac association, under licence.
• Abroad, labelling rules change. A baking powder brought back from another country must be judged on its own label, not on that of the brand at home.

A “may contain gluten” warning on a sachet without “gluten free” next to it signals a factory risk that nothing measures. For the full method, see our guide to reading labels, and for the other store-cupboard ingredients, our list of foods with and without gluten.

In gluten-free baking

A baking powder labelled “gluten free” settles the question. The rest of the recipe needs its own checks: butter is gluten free, provided the butter dish hasn’t seen any crumbs, and the worktop, tins and sieve that have been used for wheat flour must be washed, as we explain in our article on cross-contamination at home. For a savoury sauce on the side, mayonnaise has its traps too.

In short