Baking soda

Baking soda is sodium bicarbonate, a fine white powder that makes baked goods rise. It is a base, so it reacts with an acid in the recipe, such as buttermilk, yogurt, lemon juice, brown sugar, honey or natural cocoa, and gives off carbon dioxide. It is about three to four times as strong as baking powder, so recipes use only a little.

Why it works

Without an acid to react with, baking soda only gives off gas when heated, and it leaves a soapy, metallic taste and a yellow color. With the right amount of acid, it is fully used up and leaves almost no taste. It also raises the pH of the dough, which makes cookies spread more and brown more deeply.

How to use it

It goes by several names, all the same product:

• Baking soda in the US and Canada.
• Bicarbonate of soda in the UK, often shortened to bicarb in Australia and New Zealand.
• Bread soda in Ireland, from its use in soda bread.
• Bikarbonat in Sweden and Natron in Germany.

A usual amount is about ½ teaspoon of baking soda for each 240 ml (1 cup) of buttermilk or yogurt in a recipe. Mix it into the dry ingredients so it spreads evenly, and bake soon after the wet and dry parts meet, because the reaction starts at once.

Other uses:

• A pinch in onions as they cook speeds up browning, because it helps the Maillard reaction. It also makes them soft.
• About ½ to 1 teaspoon per liter of water softens dried chickpeas and beans as they soak.
• A pinch in a marinade tenderizes meat for stir-fries, as in velveting.

Substitutes

There is no simple swap. If you only have baking powder, use about three times the amount, and expect a slightly different texture and taste.

How to store it

Keep it dry with the lid tight. It lasts a long time, but test it by adding a pinch to a spoonful of vinegar. It should fizz strongly.

Common mistakes

• Mixing up baking soda and baking powder. They are not the same strength and do not work the same way.
• Leaving lumps. Sift it with the flour, or a lump can leave a bitter pocket.
• Using too much. Cakes taste soapy and turn dark.

In recipes

You will see "1 tsp baking soda", "½ tsp bicarbonate of soda" and "1 krm bikarbonat".