Baking powder

Baking powder is a chemical leavening. It is a mix of baking soda, one or two dry acids, and a little starch to keep it dry. When it gets wet, and again when it gets hot, the soda and acid react and give off carbon dioxide. The gas bubbles make cakes, muffins, pancakes and quick breads rise without yeast.

How to tell it is done

To check if your baking powder still works, stir ½ teaspoon into 60 ml (¼ cup) of hot water. It should fizz strongly right away. If it barely bubbles, replace it.

Why it works

Baking soda is a base. It needs an acid to release gas. Baking powder carries its own acid, so it works in batters made only with milk, water or eggs, which are not acidic. Because the reaction starts as soon as it gets wet, get the batter into the oven soon after mixing. Double-acting powder buys you a little time, since part of the rise waits for the heat.

How to use it

Baking powder has the same name in English everywhere. Other names you will see:

• Double-acting baking powder in the US. This is the usual kind there. It releases some gas when mixed and the rest in the oven.
• Bakpulver in Swedish recipes and Backpulver in German ones. They are used the same way.

A common amount is about 1 to 1½ teaspoons per 125 g (1 cup) of all-purpose flour. Recipes with buttermilk or yogurt often use less baking powder and add some baking soda.

Substitutes

• For 1 teaspoon baking powder, use ¼ teaspoon baking soda plus ½ teaspoon cream of tartar.
• Self-rising flour already has baking powder in it. Leave the baking powder out if you use it.
• In some Swedish cookies, hjorthornssalt (baker's ammonia) does a similar job and gives a very crisp result.

How to store it

Keep the lid tight and the tin in a dry cupboard. Moisture sets off the reaction slowly, so baking powder loses strength after about 6 to 12 months once opened.

Common mistakes

• Using baking soda when the recipe says baking powder. Soda is about three to four times as strong and tastes soapy without acid.
• Adding extra for a better rise. Too much makes cakes rise fast, then sink, and taste bitter.
• Letting the batter sit for an hour before baking.

In recipes

You will see "2 tsk bakpulver", "1 tsp baking powder" and "1 level teaspoon baking powder".