If you’ve ever looked closely at the baking powder canister in your pantry, you might have seen “double-acting” or “single-acting” printed on the label. But what do these terms really mean, and how do they affect baking?
What Is Baking Powder?
Baking powder, like its counterpart baking soda, is a leavening agent that helps doughs and batters rise. Unlike baking soda, however, baking powder is a complete leavening agent, containing both an alkaline component (baking soda) and the acid needed to trigger a reaction in one package.
The distinction between double-acting and single-acting baking powder lies in the type of acid used alongside the alkaline baking soda.
Single-Acting vs. Double-Acting Baking Powder
Double-acting baking powder generates gas bubbles twice: initially when mixed with liquid and again when exposed to heat. As food scientist Harold McGee describes in On Food and Cooking, they produce an initial set of gas bubbles when the powder is combined with batter and a second set during baking.
As McGee explains, different acids in baking powders influence the pattern of gas production. Most supermarket double-acting baking powders combine sodium bicarbonate (baking soda) with monocalcium phosphate (MCP) and sodium aluminum sulfate (SAS), allowing reactions both during mixing and with heat.
In contrast, single-acting baking powder only causes one reaction upon contact with liquid. This means its leavening action occurs entirely at the beginning.
Tip: Because single-acting baking powder only reacts once when mixed with liquid, it’s crucial to get the batter into the oven quickly after mixing to ensure optimal rise and preserve the valuable gas bubbles produced.
The Best Baking Powder for Home Baking
For home bakers, double-acting baking powder is commonly found in stores and is the preferred choice for everyday use. Single-acting versions are typically reserved for commercial use.
If you come across commercial-grade single-acting baking powder or have a recipe that specifically calls for it, you can usually substitute with double-acting baking powder without issue. When recipes mention “baking powder” without specifying, they generally mean double-acting, which is ideal for all your home baking needs.
