by Jeff Potter
Baking Powder
Baking powder solves the "balancing act" problem encountered when using baking soda by including acids alongside the bicarbonates. And since the acids are specifically mixed into baking powder, they can be optimized for baking; you don’t have to rely on whatever acids happen to be present in the food being made.
Baking powder, at its simplest, can be made with just one type of bicarbonate and one type of acid. This is why, in a pinch, you can make your own baking powder: 2 parts cream of tartar to 1 part baking soda. Cream of tartar—potassium hydrogen tartrate—will dissolve in water, freeing tartaric acid (C4H6O6) to react with the sodium bicarbonate.
Commercial baking powders are a bit fancier than this, though. Different acids have different rates of reaction and reaction temperatures, so using multiple types of acid allows for the creation of a baking powder that’s essentially time-released. This isn’t just clever marketing: in baked goods, if the CO2-generating reaction occurs too slowly, you’ll end up with a dense, fallen product. And if those reactions happen too quickly, the food won’t have time to properly set so as to be able to hold on to the gas, resulting in things like collapsed cakes.
Note
Some people find that baking powder made with sodium aluminum sulfate tastes more bitter than that made with other acids, such as monocalcium phosphate.
Double-acting baking powder—this is the stuff you’ll find at the grocery store—uses both slow- and fast-acting acids to help prevent these types of problems. Fast-acting acids, such as tartaric acid (in cream of tartar) and monocalcium phosphate monohydrate, can work at room temperature; slow-acting acids, such as sodium aluminum sulfate, need heat and time to release CO2. As long as the ratio of ingredients in your baked products is roughly correct and you’re baking within an acceptable temperature range, baking powder is unlikely to be the culprit in failed baking experiments.
Still, if you’re getting unexpected results with a commercial baking powder, check whether your ingredients are highly acidic. Acidity impacts baking powder; more acidic ingredients in a recipe will require less baking power. If that doesn’t turn up any suspects, check how long it has been since the baking powder was opened. Even though commercial baking powders contain cornstarch, which absorbs moisture to extend the shelf life, the chemicals in baking powder will eventually react with each other. Standard shelf life is about six months after being opened.
Pizza Dough—Yeast-Free Method
While baking powder is most commonly used in sweets, it can be used in savory applications, too. Try making a quick-rising pizza dough—especially handy if someone has a yeast allergy.
Whisk 3–4 cups (360–480g) of flour with 1 teaspoon (6g) of salt and 2 teaspoons (10g) of baking powder. Add 1 cup (240g) of water and knead to create a dough that has roughly a 66–75% hydration level. Let rest for 15 minutes and then proceed with par-baking instructions as described in Pizza.
Pumpkin Cake
There are two broad types of cake batters: high-ratio cakes—those that have more sugar and water than flour (or by some definitions, just a lot of sugar)—and low-ratio cakes—which tend to have coarser crumbs. For high-ratio cakes, there should be more sugar than flour (by weight) and more eggs than fats (again, by weight), and the liquid mass (eggs, milk, water) should be heavier than the sugar.
Consider this pumpkin cake, which is a high-ratio cake (245g of pumpkin contains 220g of water—you can look these sorts of things up in the USDA National Nutrient Database, available online at http://www.nal.usda.gov/fnic/foodcomp/search/).
In a mixing bowl, measure out and then mix with an electric mixer to thoroughly combine:
1 cup (245g) pumpkin (canned, or roast and puree your own)
1 cup (200g) sugar
¾ cup (160g) canola oil
2 large (120g) eggs
1 ½ cups (180g) flour
¼ cup (40g) raisins
2 teaspoons (5g) cinnamon
1 teaspoon (5g) baking powder
½ teaspoon (5g) baking soda
½ teaspoon (3g) salt
½ teaspoon (2g) vanilla extract
Transfer to a greased cake pan or spring form and bake in an oven preheated to 350°F / 175°C until a toothpick comes out dry, about 20 minutes.
Notes
Try adding dried pears soaked in brandy. You can also hold back some of the raisins and sprinkle them on top.
One nice thing about high-ratio cakes is that they don’t have much gluten, so they won’t turn out like bread, even with excessive beating. With a total weight of 920 grams, of which only roughly 20 grams is gluten, there just isn’t enough gluten present in this cake to give it a bread-like texture. There’s also a fair amount of both sugar and fats to interfere with gluten development.
If you’re making a quick cake like this pumpkin cake as the finale to an informal dinner party, try serving it directly on a single plate or even a cutting board. Besides lending a pleasant casual feel, this’ll mean fewer dishes to wash!
Tim O’Reilly’s Scones and Jam
Tim O’Reilly is the founder of O’Reilly Media, which started out as a publisher of technical books and has more recently branched out into offering content in a variety of media, running technical conferences, hosting online and in-person workshops, and creating other ways to spread the knowledge of innovators. (This book is published by O’Reilly Media.) Above, Tim shows his method for drying apples: sliced into rings, arranged on a window screen, and left to dry in the hot and dry California sun.
You say you don’t consider yourself a foodie at all?
No. In fact, I kind of make a small number of things that I make repetitively. A lot of what I do is driven by the fact that I hate to waste things. So hence jam because there’s all this great fruit. [Tim has numerous fruit trees.] Right now I’m doing dried apples. But let me put these scones in. [Tim had been making scones as we started.] This is something that I figured out a long time ago. I make this big batch and it’s too much for two people so I made a batch and then I was like, oh wait, I can just freeze it.
How did the thought of freezing it come to you?
Oh, I don’t know, it was just sort of like duh. It’s sort of like so obvious. You just make it and freeze it and then I have it and I can throw in a bunch. When somebody visits it literally just takes me a few minutes. The raspberry jam—I have raspberries, but I don’t have enough to make jam all at once, but I’ll go out and pick them every day and now you can see what I’ve now got... [Tim holds up a bag of frozen raspberries.] By the time I get two of these bags I’ll have enough to make raspberry jam. You don’t have to do it all at once.
What’s your favorite kitchen tool?
I like things that seem magical. When you see this particular apple peeler-corer-slicer, you’ll go, "Oh! That’s so cool! It’s magical." It just does a fantastic job.
Tim O’Reilly’s Jam-Making Tips
Tim says there are two secrets for making jam:
Use a low-methoxyl pectin, such as Pomona’s Universal Pectin. Unlike standard pectin, which requires sugar to create a gel, Pomona’s is activated by calcium. This basically takes one variable out of the picture, in the sense that you don’t have to add sugar for both taste and stability, but just for taste.
Throw some spoons in the freezer before you start. When making the jam, drip the hot jam onto the cold spoon to let it cool, and then you can tell whether it has a good gel or not.
With these two points in mind, you’re totally free to experiment with flavor, because that’s the only variable left to optimize.
Tim O’Reilly’s Scone Recipe
In a bowl, measure out:
2½ to 3 cups (350–400g) flour (experiment to see how much you prefer)
½ cup (115g) butter, chilled
Using a pastry blender or two knives, cut the butter into the flour. When done, the butter and flour should look like small pebbles or peas.
Add and whisk to combine:
3 tablespoo
ns (36g) sugar
4 teaspoons (20g) baking powder
½ teaspoon (3g) salt
(At this point, you can freeze the dough for later use.)
In the center of the dough, make a "well" and add:
½ to 1 cup (50–100g) currants (or raisins, if you prefer)
½ to 1 cup (130–260g) milk (or soy milk; goat milk is also great)
Stir with a knife until you get just shy of a gooey consistency. Start with only ½ cup (130g) of milk, adding more as necessary until the dough begins to hang together. If it gets very sticky, you’ve put in a bit too much milk. You could add more flour if you’ve gone in with less flour to begin with. It’s better to bake them sticky than to add more than a total of three cups of flour: the stickiness is just a problem for shaping them, since it sticks too much to your fingers; too much flour, and they can become tough.
Prepare a baking sheet by lining it with parchment paper or a Silpat (nonstick silicone baking mat). If you don’t have either, lightly grease a baking sheet. (You can just rub it with the paper from the stick of butter.) Using your hands, shape the dough into small lumps spaced evenly on the baking sheet.
Bake at 425°F / 220°C until the tops are browned, about 10 to 12 minutes.
Serve with jam, and, if you’re feeling piggy, with Devonshire cream (whipped cream works, too, from one of those aerosol cans, so you can just put a spot of it on).
Tim’s homemade strawberry jam on "bottom" of currant scones. Tim pointed out that it’s easier to flip the scone over and jam the bottom side of it, instead of trying to slice it open.
Notes
You can use a cheese grater to grate the butter into the flour. Chill the butter for a few minutes so it’s easier to handle.
Tim freezes the partially mixed dough, adding the milk and currants to the dough after it’s pulled out from the freezer. (The frozen dough has an almost sand-like consistency, so you can pull out as much or as little as you want.) The benefit of the frozen dough is that you can bake scones a few at a time, adding just enough milk to bring the cold dough to a sticky consistency. This makes for a great quick treat, especially if you are the type that has unexpected guests occasionally. It’s also in the spirit of learning to cook like a pro: nothing goes to waste this way, and it’s efficient!
Mechanical Leaveners
Mechanical leaveners work by trapping air within a liquid—usually by whipping egg whites, egg yolks, or cream—or by generating steam from water present in the food.
Unlike biological or chemical leavening methods, which rely on the chemical makeup of the food to generate air, mechanical rising techniques rely on the physical properties of the food to hold air. Because of this, mechanical leaveners can’t just be added to a dish without considering the impact of the moisture or fat that they also add, which can throw off the ratios between ingredients such as flour and water or sugar and fats.
Note
"Cream the butter and sugar" has nearly three million exact-phrase matches on Google, and plenty is written about the microscopic air bubbles that the sugar crystals drag through the butter when creamed. When you see a recipe call for creaming butter and sugar, use room-temperature butter—it needs to be plastic enough to hold on to the air bubbles but soft enough to be workable—and use an electric mixer to thoroughly combine the ingredients until you have a light, creamy texture.
Egg Whites
Whisked egg whites are the Styrofoam of the culinary world: besides acting as space fillers in cakes, waffles, and soufflés and as "insulators" in desserts like lemon meringue pie, when overcooked, they taste about the same as Styrofoam, too. All metaphors aside though, egg whites are much more forgiving than many cooks realize. With a little attention spent on understanding the chemistry and a bit of experimentation, egg-white foams are easy to master.
Note
A foam is a mixture of a solid or liquid surrounding a dispersion of gas; that is, the gas (usually air) is dispersed through the liquid or solid, not in a single big cavity. Bread is a solid foam; whipped egg whites are a liquid foam. (See Buying Food Additives in Chapter 6 for a description of colloids.)
The key to understanding egg whites is to understand how foams themselves work. Whisking egg whites turns them into a light, airy foam by trapping air bubbles in a mesh of denatured proteins. Since regions of the proteins that make up egg whites are hydrophobic—literally, water-fearing—they normally curl up and form tight little balls to avoid interacting with the water. But when whisked, those regions of the proteins are slammed against air bubbles and unfold, and as more and more proteins are knocked against an air bubble, they form a layer around the bubble and essentially trap it in the liquid, creating a foam that’s stable.
Oils—especially from egg yolks or any trace oils present in the whisking bowl—prevent egg whites from being whisked into a foam because they’re also able to interact with the hydrophobic sections of the proteins. Water and sugar don’t interfere with the formation of protein-based foams for the same reason.
Once the air bubbles are encapsulated by the proteins in the egg white, it takes quite a bit of effort to get them to break. Exposing the whites to any oil before whisking is a problem; even a trace amount of fat from a small amount of stray egg yolk will interfere with the creation of the foam. But once the eggs are whisked, they’re much more resilient. Try this experiment: whisk an egg white to soft peaks, then add ½ teaspoon (5g) olive oil and continue to whisk. It might surprise you how long it takes before the oil starts to noticeably interact with the foam, and even then, that the foam remains mostly stable.
What Should You Whisk Your Egg Whites In?
Definitely not plastic. Copper bowls work best; a clean stainless steel or glass bowl is fine.
Plastic is chemically similar enough to oil that oil molecules stick around on it and are impossible to completely remove. Whisking egg whites in plastic bowls doesn’t produce as good a result because there’s enough oil lingering on the surface of the bowl to interfere with the development of the foam. (Of course, it’s fine to whip cream in a plastic bowl; more fat isn’t going to interfere with the fat-based foam structure.)
When you use a copper bowl, trace amounts of copper ions interact with the proteins in the egg whites to make a more stable foam. It’s not a subtle effect: egg whites whisked in copper bowls are definitely easier to work with. Copper bowls are expensive, but if you find you’re whipping up egg whites a lot, it’s probably worth breaking down and spending $40 on one.
For more occasional use, most of us have stainless steel or glass bowls on hand, and those are fine. While these materials won’t help with the egg-white foam by adding copper ions, they also won’t hold on to problematic fats. Cream of tartar is commonly used as a chemical buffer—any time you see a recipe calling for egg whites to be whisked and you’re using stainless steel or glass, "auto-complete" it with a pinch of cream of tartar (⅛ teaspoon [½g] per egg white). Don’t use cream of tartar in a copper bowl, though; it’ll interact with the copper.
Try an experiment: whisk three whites in a plastic bowl, three whites in a stainless steel or glass bowl, and, if you should happen to have a copper bowl, three whites in a copper bowl. Take a spoonful of the resulting foams and smear it on a cookie sheet to compare the difference between the foams.
Egg whites whisked to stiff peak in a stainless steel bowl (left) and a copper bowl (right), smeared on a cookie sheet to show the difference in texture.
Meringues
Egg whites, when whisked and combined with sugar, turn into a sweet, airy mixture suitable for folding into heavier bases, bringing a lightness and sweetness. Of course, sugar and egg whites are pretty good on their own—meringue cookies are nothing more than egg whites and sugar that have spent a little time in the oven. The sugar isn’t just for taste, though; it helps stabilize the egg-white foam by increasing the viscosity of the water present in the foam, meaning that the cell walls in the foam remain thicker and are thus less likely to col
lapse. Net result? The meringue is better able to support the weight of anything you add into the foam.
Stirring and Whisking
When whisking, think about the goal. If you’re trying to whisk air into the food to create a foam, such as whipped cream or whipped egg whites, whisk—preferably by hand!—in an up-and-down circular motion, catching and trapping air. If you’re trying to mix ingredients together without necessarily adding air, whisk in a flat circular motion. This is especially important for dishes like scrambled eggs, where incorporating air actually reduces the quality.
I prefer whisking things by hand. Why? Electric beaters won’t work in as much air before the foam is set because of the motion of the beaters. Also, when whisking, avoid tiny little stirring motions. This is true for stirring almost anything, whether you’re holding a whisk or a spoon. Sautéing vegetables? Either get in there like you mean it, or don’t touch them; just let them sit so that they brown. Likewise, when whisking foams, get in there like you mean it and whisk some air in there!
Once you’ve got the motion down, how do you know when it’s done? It depends on the recipe. If it calls for soft peaks, the foam should still be supple and pliable, but if it calls for firm or stiff peaks, the foam should hold and set its shape; stiff peaks should be firmer and glossier than firm peaks. (See Making Whipped Cream in Chapter 1 for more photographs of cream whipped to various states.)
