Two things can be said about the young adults of America today, and they can be said with arguable certainty. One is that they are struck by a wanderlust, a restlessness. It is hard to know if this sentiment is an earnest desire to constantly pick up and go, embrace apartments of unknown integrity and the internet for employment opportunities, take life by the reigns, for better or for worse, come what may, thus beefing up life with a full repertoire of places, experiences and stories for the grandchildren. The feeling may instead stem from the lack of a clear and specific destination in life. Or perhaps it's just a fad. In any case, if George Gibbs were around in 2007 he would probably have felt more compelled to follow the voice telling him not to get married to Emily Webb and would have taken a break from Grovers Corners instead.

The other fact about the folks of this crowd is that, from time to time, they enjoy baking desserts. Brownies and chocolate chip cookies would probably rank high favorites if there were a Family Feud category, but so would other delights, such as the oatmeal cookies-meet-fudge dish dubbed "Supremes", the deep-dish cousins of the chocolate chip cookie known as "Congo Bars" or the let-us-now-rid-our-kitchen-of-all-things-sweet option, "Garbage Cookies".

Here is the dilemma: sometimes, what with all of this moving around, and this busyness associated with not settling down, certain kitchen sundries go missing. Either it's a new apartment, and there hasn't been a chance to stock the cupboard with all-purpose, wheat and soya flour, or there just hasn't been occasion to do so because black bean quesadillas and Nutella on toast has been a homerun dinner/dessert combo for the entirety of winter. Further confounding the problem, 24-hour bodegas aren't always right around the corner, even though they are sometimes. While some would argue (somewhat banally) that necessity is the mother of a brand-new idea, leading to an invention of sorts, others would shake their heads and say, well, dang. These folks know how good a true-blue chocolate chip cookie really is.

When it comes down to it, there are a number of age-old substitutions that can lead someone out of this very pinch -- the binding quality of eggs can be replaced by tofu (?!), potato starch, arrow root or even applesauce, for instance -- yet there are certain things that just shouldn't be swapped on a whim. I'm talking about baking powder and baking soda here.

For beginners, there are three things that every good pastry chef should know:

1. If you don't have baking soda, you can substitute baking powder for the soda in a recipe, but you'll have to add a bit more than the recipe calls for, and it may affect the final taste. If in doubt, make the dessert sweeter, as swapping in the powder may make things a bit more bitter.
2. The logic is not reciprocal. That is, you can never simply substitute baking soda for baking powder, but --
3. To make baking powder using baking soda, just mix two parts cream of tarter with one part baking soda, and voila. (Note that sometimes a little buttermilk or lemon juice can allow the elimination of the cream of tarter, and read on for details).

The science behind these simple chemical leavening agents is just as simple as a third grader's diorama -- you know, the one with a paper mache volcano spewing forth an acidic spume that was supposed to be lava. In fact, that very reaction between baking soda, also called sodium bicarbonate, and vinegar, your favorite acid, follows the same chemistry that causes cookie dough to rise. In this particular case of chemistry, an acid reacts with bicarbonate, a base, to produce carbon dioxide gas. In baking, the soda serves as the base, and the dough, when moistened, is acidic enough to cause a bubbly reaction. That reaction releases carbon dioxide, which is trapped in the dough and causes the leavening action.

Baking powder, which contains the basic (read: opposite of acidic) salt baking soda (read: sodium bicarbonate), only differs in that it contains an acidic element as well -- that little tin is filled with a dessicated mixture of acid and base which only need some water to make them soluble and reactive with each other. In the case of Rumford, the acid is calcium phosphate. Others, like Calumet (which, by the way, means "peace pipe" in another language) also contain sodium aluminum phosphate, another acid. The provided acid is important to note because some (calcium phosphate) are reactive at room temperature while others (aluminum phosphate) are more reactive in the heat of the oven. Recipes will tell you not to mix the dough too much after the soda or powder is mixed with the liquids because doing so will release some of those CO₂ bubbles and cause a flatter baked good.

Those are pretty much the basics...but there are always further explanations. Sometimes what's stocked in the kitchen really isn't working with a recipe. Say, for instance, that there is no baking powder, and nor is there cream of tarter -- a common problem among the transient, young workforce. There should be no fear. Just add a smidgen of science and let the situation rest a minute, open up the fridge, and look for something...acidic. Why? Because that cream of tarter is nothing but potassium bitartrate, which itself is an acid salt, and is a substitute ingredient in baking powder because it gives the baking soda something to react with. In other words, if the recipe calls for some yogurt, a bit of lemon juice, citric fruit or any other possibly acidic ingredient (apples, strawberries, pineapples, raisins, sour cream, buttermilk...), you're just as well off subbing baking soda alone to replace the powder.

A little science certainly goes a long way in the kitchen. History is the same way; some say it is our greatest resource. Indeed, if it weren't for Eben Norton Horsford, a scientist and culinary innovator, baking powder wouldn't be in the kitchen cabinet, and the biscuits of today would probably taste pretty yeasty. Now that would be a shame.

« Previous Next »