What is baking powder? All you need to know about baking powder

classic cake ingredients including baking powder
(Image credit: Getty)

What is baking powder and why is it important in baking? We answer all your baking powder-related questions and explain how it’s different from baking soda.

You may have noticed a common ingredient in all your favourite bakes and it’s not just a coincidence. It is a chemical-raising agent that helps your cakes and bakes increase in volume while cooking for a fluffy, light rise.

From your go-to cupcake recipe, that fail-safe chocolate cake recipe, or lemon drizzle cake which you've baked time and time again, each recipe lists baking powder in the ingredients and it’s incredibly important for achieving the best final bake.

What is the difference between baking powder and baking soda?

In The Pastry Chef’s Guide, British pastry chef Ravneet Gill explains: "Bicarbonate of soda works by reacting to acidity, to create carbon dioxide, which causes your cake, cookie or biscuit mixture to expand and rise."


Baking powder, on the other hand, is a leavener made up of baking soda, cream of tartar, and a filler, which is most commonly in the form of cornflour. It has a more neutral taste than baking soda but using too much of it can still cause baking disasters as we explain below.

Ravneet explains: "Cream of tartar is an acid, so it essentially contains its own acid. It is used to lighten the texture of cakes, biscuits etc. and increase volume."

Ever wondered why your cake doesn’t start rising until midway through the cooking? It’s because the baking powder has two reactions, first when it gets wet and then again when heated. This comes with advantages, as it means it’s less essential for the mixture to be placed straight in the oven after mixing. According to Leith’s Baking Bible, baking powder also produces a more reliable rise.

Does baking powder expire?

Because baking powder contains active ingredients, it does not last forever and therefore can expire. If you use it when expired, it isn’t dangerous but it will likely not produce the results you wanted. It reacts to heat and moisture so it’s important to store it in a cool, dry place and try to use it within the given expiration date.

Can too much baking powder ruin a cake?

Yes, too much baking powder can ruin a cake. Not only could using too much ruin the taste of your cake, but it will also cause the cake to rise and increase in volume too rapidly. The cake will then sink during cooling. See our feature; ‘What’s wrong with my cake?' for more baking troubleshooting.

The below video shows the difference as little as half a teaspoon too much can make.


Using too much baking soda will also ruin your cakes and bakes and is likely to leave an unpleasant taste in your mouth. If your finished bake tastes bitter or soapy it’s likely because you’ve used too much baking soda and too little acid, such as citrus juice, buttermilk, or chocolate. Ravneet advises you to increase the acid or decrease the baking soda in the recipe to fix this.

Why does the recipe require baking powder and baking soda?

Cookies made with baking powder

Always follow the recipe and make sure you stick to the correct amount of ingredients

If you’ve noticed that a recipe calls for baking powder and baking soda, like our Quinoa crunchies, for example, it’s important that you listen. This is because the recipe requires an extra boost in order to achieve the best rise. If you omit it, you’ll likely find that the cake or bake has not risen as much as you’d hope.

Is baking powder gluten-free?

While both baking powder and soda are naturally gluten-free. Some brands may use wheat starch in the ingredients or process the ingredients in environments that also manage items containing gluten. Therefore it’s always best to buy gluten-free marked options or check the ingredient list if you have an allergy.

What else can I use it for?

Baking soda is a popular alternative to many cleaning products. It is made up of some baking soda, you can use it for cleaning too. You will likely not yield the best results as it only contains a portion of soda but it’s a good affordable option and worth a try.

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Jessica Ransom
Senior Food Writer

Jessica is a freelance food writer, stylist and recipe tester. She previously worked as Senior Food Writer at Future. While at Future Jessica wrote food and drink-related news stories and features, curated product pages, reviewed equipment, and developed recipes that she then styled on food shoots. She is an enthusiastic, self-taught cook who adores eating out and sharing great food and drink with friends and family. She has completed the Level 1 Associate course at the Academy of Cheese and is continually building on her knowledge of beers, wines, and spirits.