How Julia Child Would Test Baking Powder Before Using
Chef and food media super-celebrity Julia Child was a library of tips and tricks gleaned from professional chefs and home cooks alike. She would dole out these tips to burgeoning cooks who were apprehensive about the nuances of the kitchen and even more-seasoned kitchen denizens looking to up their game. As noted by WiseBread, Child implored her viewers to wring the excess liquid from their spinach, to use butter in addition to oil when sautéing, and to give omelets a good shake for the perfect French form.
These helpful hints extended well into the world of breads, baking, and pastries, such as her advice on the importance of and how to properly fold ingredients together, a technique that often appears in recipes for meringues and delicate batters. She was also keen on cooks making sure that they were getting the most effective use out of their ingredients, and nowhere was that more apparent than in her advice for testing out baking powder.
How to know if your baking powder is too old?
What is baking powder? Well, as noted by The Food Network, it's a leavening agent made from baking soda (sodium bicarbonate) an acid salt, and cornstarch. The acid salt in baking powder reacts only once liquid is added.
Though baking powder will never spoil in the sense that a meat, dairy, or plant will, it will lose its potency somewhere around the six-month mark (via Does It Go Bad?). The result, as LiveStrong notes, will be dense baked goods with a less-than-impressive rise.
Along with a few other tips compiled in Epicurious, Julia Child offered a simple, but effective way for cooks to test their baking powder before using it in their batch of cookies or cake. Just get a half cup of hot water and stir in a teaspoon of baking powder. It should begin to bubble actively. If it doesn't, it's time to move on to a fresh container.
Fret not, though, if you find you have the better portion of a container of past-prime baking powder; it still has some life left in it. ABC News notes that you can still use the baking powder to clean countertops and vinyl floors, as a water softener, or even as an air freshener.