If you are a baker, you know that many of the items you bake need to rise to achieve a proper result. There are different ways in which to get your item to rise and they all involve some type of leavening agent. What these leavening agents are and how to use them is the subject of this Cooking Tip.
There are three main categories of leavening agents – Chemical, Biological and Physical/Mechanical.
- Chemical – These are ingredients that use a chemical reaction that releases gas bubbles into your baked goods, thereby causing them to rise. These are generally used in cakes and quick breads. There are two main chemical leavening agents.
- Baking Soda is also known as bicarbonate of soda or sodium bicarbonate and is an alkaline substance. When combined with an acidic ingredient (vinegar, lemon juice, buttermilk, yogurt), a chemical reaction occurs that produces CO2 gas bubbles, causing the batter or dough to rise. Because this chemical reaction occurs immediately upon moistening the baking soda with the acidic ingredient, it should be mixed with the other dry ingredients before adding any liquid. Also, the batter should be placed in the oven immediately after combining or you will lose the lift it provides.
- Baking powder is a mixture of baking soda, an acid (often cream of tartar) & a moisture absorber (such as cornstarch). It does not require an acid to activate it. When mixed with a liquid, it also produces CO2 gas bubbles that aid in rising. Most commonly found in our stores is double-acting baking powder. It releases some gas upon mixing with a liquid but the rest is released when exposed to the heat of the oven.

- Biological/Organic
- These are naturally occurring microorganisms that act in the fermentation process of baking. These agents break down sugars and produce CO2 gas bubbles. The main one of these that we use is Yeast. Please see this Cooking Tip for a more in-depth discussion of yeast. Sourdough starter is another example. These are essential to bread making.
- Mechanical/Physical
- This involves you putting air into the batter or dough by mixing the ingredients. As you whisk or beat things in your mixer, you are rapidly introducing air into your mixture. A common method is whipping eggs or just egg whites until they are full of air and then carefully folding in other ingredients. You must take care in this step as you do not want to deflate all that air you just put into it.
- Steam is another example of physical leavening. Steam is produced by evaporation of water as the temperature increases. The gas that is produced by this lifts your baked good.
Both baking powder and soda lose their effectiveness over time. The shelf life of properly-stored (kept dry and cool) baking powder is 6 months to a year. For soda, it is 8 months to a year. Put the date you open these items on the canisters so you know how old they are.
There are tests you can do to see if they are still effective. For baking powder, put 1 teaspoon in ½ cup of hot water. It should bubble immediately and foam to the top. For baking soda, put 2 tablespoons of white vinegar in a cup. Add 1 teaspoon of baking soda. Stand back as it should froth like crazy. If your powder and/or soda does not react like this, throw it out. Just a caution – there are experts who feel that these tests don’t tell the whole story. They have determined that your baking powder and soda do not yield the same lift as they get older even if they perform well on the above tests. They recommend replacing these items every six months routinely.
One tidbit – you can make your own baking powder. Mix one part baking soda with one part cornstarch & two parts cream of tartar. Store in a cool, dry place for several months.
A last caution is for those of you who live at high altitude. The increased elevation, which leads to lower air pressure as well as a change in the temperature at which water boils, can cause problems with the rising of your baked goods. For a more thorough discussion, see this Tip on High Altitude Baking.
I hope this Tip demystifies those all-important leavening agents for producing delicious and airy baked goods!