Cooking for Geeks: Real Science, Great Hacks, and Good Food (48 page)
Read Cooking for Geeks: Real Science, Great Hacks, and Good Food Online
Authors: Jeff Potter
Tags: #COOKING / Methods / General
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.
You did calibrate your oven, yes? If not, see the sidebar
The Two Things You Should Do to Your Oven RIGHT NOW
in
Chapter 2
.
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 (C
4
H
6
O
6
) 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 CO
2
-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.
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 CO
2
. 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.
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
.
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 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.
In a bowl, measure out:
- 2 ½ 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 tablespoons (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!