Why You Should Make Homemade Baking Powder
Here, in no particular order, is a quick lesson in kitchen science, a route to better tasting biscuits and other baked goods, and a handy tip in case you run out of baking powder and can't get to the store to buy more. Making your own baking powder requires just two ingredients and takes a mere moment. Try it in a favorite recipe and see if you can taste the difference.
Food writer Jane Lear swears by a DIY baking powder blend for her favorite buttermilk biscuit recipe, which comes from the Southern chef Scott Peacock, co-author with Edna Lewis of a beautiful cookbook called The Gift of Southern Cooking: Recipes and Revelations from Two Great American Cooks ($59.71, amazon.com). Let us quickly diverge: Edna Lewis is, of course, the chef and culinary legend whose book The Taste of Country Cooking, ($134.60 amazon.com), is among the most important American cookbooks. Peacock is also a celebrated chef himself and began making his own baking powder after working with Miss Lewis. As he explained in their book, Miss Lewis was "distressed" by the metallic aftertaste of commercially available "double-acting" baking powders, which often contain sodium aluminum sulfate, among other chemicals. She began mixing a simple combination of baking soda and cream of tartar, to mimic the "single-acting" powders of the past. (These same "single-acting" powders are much like the ones sold in parts of Europe, where "double-acting" versions are not as widely available.)
The baking powder sold in most American grocery stores is labeled "double-acting" and is not interchangeable with baking soda, but what does that mean? Baking soda and baking powder are leavening agents, meaning that they cause baked goods to rise. How they rise and when depends on their chemical makeup. Baking soda is pure alkaline, or a base. When it's mixed with an acidic ingredient, like lemon juice, vinegar, or buttermilk, it causes a chemical reaction that creates carbon dioxide.
Baking powder is actually made of baking soda, but with an acidic ingredient added, usually cream of tartar, and often a thickener like cornstarch. If it's single-acting powder, then the chemical reaction occurs when it's mixed with the liquid in a recipe. Double-acting baking powder is formulated to react twice—once when it encounters the liquid, and again when the mixture meets the heat of the oven. The odium aluminum sulfate and other chemicals of the commercial blends are added to encourage that later reaction.
Even if your palette isn't quite as sensitive as that of Miss Lewis (or Scott Peacock or Jane Lear, either), you will taste a difference when you bake biscuits with homemade baking powder. Even slathered with butter and jam, the difference in taste will be noticeable. The richness of the butter and the tang of the buttermilk will be more pronounced.
It is worth noting that since the DIY blend does not contain any ingredients to promote double action, you have to act faster when baking with it. Don't let the uncooked batter or dough sit too long, or the baked goods could fall a little flat. As Marion Cunningham explains in The Fanny Farmer Baking Book, "Homemade baking powder is perfectly efficient, but remember that it is single-acting, so once you’ve combined the ingredients, pop the batter right into the oven so you don’t lose any 'oomph.'"