Tune in to Science Friday on December 12, when
Cooking for Geeks author Jeff Potter talks cookie science.
The perfect cookies or a beautiful loaf of bread can take center stage at a holiday celebration. But if you’re tired of the traditional recipes, why not mix things up? This season, try replacing the sugar, switching up the flour, mimicking an egg, or going butter-less.
The important thing to remember when baking or cooking is that “experimentation is the name of the game,” says Jeff Potter, author of Cooking for Geeks
and a guest on Science Friday. “When you’re doing a substitution, you are making a guess,” he says, so keep track of what you did and of what happens. If need be, adjust the recipe accordingly, and try it again.
Science Friday caught up with Potter and culinary scientist Ali Bouzari, another SciFri guest, for baking ingredient twists—and scientific insight into why they work. (Listen to Bouzari’s segment here
, and Potter’s most recent segment here
If you want to substitute ingredients, Potter says it’s important to ask, “What’s the role that the ingredient is playing in this recipe?” In the case of butter, its roles entail lending structure to your baked goods, making them tender, and adding flavor.
A stick of butter is an emulsion, formed from tiny bubbles of water embedded in fats. Those fats are mostly saturated, consisting of long, straight chains of carbon and hydrogen that form a solid at room temperature. If you want a substitute for butter, you have to find the same butter-like properties within different compounds. Besides the obvious—margarine— Potter suggests baking with coconut oil, because it's also solid at room temperature, as opposed to safflower or canola oil.
And for the adventurous cooks interested in jazzing up their French pastries, Bouzari suggests an unusual fat: “You use butter because it’s a saturated fat, solid at room temperature, and it lets you mold it,” he says. “There’s really no reason you couldn’t do that with duck fat—that would be really interesting, the idea of a duck fat croissant.” Note that whereas butter is roughly 80 percent fat and 20 percent water, duck fat is pure fat, so you’ll probably need to add some water to your recipe.
FUN WITH FLOURS
Bread is a finely forged construction. Its shape, whether flat and chewy or airy and crunchy, comes from a combination of proteins that, upon meeting water, combine to make gluten. Multiple gluten molecules together form a 3-D lattice-like structure. Different types of wheat flour contain different amounts of the proteins that make up gluten—and the more gluten, the stronger the lattice will be. For instance, a baguette has a rigid structure because it’s made from wheat flour with a higher gluten content. Cake-like, tender breads, on the other hand, use softer flour that forms less gluten.
If you’re bored with wheat bread, Bouzari suggests replacing most of the flour with rye flour for a sour kick and added nutrition. The proteins in rye that form gluten are slightly different than those in wheat flour, and they can’t form as strong a lattice. But rye is also full of sticky, gummy polysaccharides—long, repeating chains of carbohydrates—that help fill in the 3-D structure.
You can’t go all-out and rely only
on rye flour, however. “Those polysaccharides are not quite as good as wheat gluten at making the network,” says Bouzari, so you need to include some wheat flour. Bouzari adds that any substitution works better if you’re able to include some of the original ingredient to get the desired structure. (Hear more about the science of bread making in this SciFri segment
, with Jack Bishop from America’s Test Kitche
THE EGG CHALLENGE
“If I run out of eggs at home,” says Potter, “almost everything grinds to a halt.”
Eggs fill so many baking roles. They contain hundreds of different proteins, some of which form a web that traps air. But eggs can also act as a binder to provide moisture, as an emulsifier, and as a leavening agent.
But for people with allergies, or for those on a vegan diet, eggs aren’t an option—and many of the so-called egg substitutes that are commercially available still incorporate some egg products. (Recall that it’s easier to substitute when some of the original ingredient is incorporated.)
One stand-in that manages to mimic an egg’s consistency, and even color, is ground flaxseeds. (Try one tablespoon flaxseed meal and two tablespoons oil or water to replace one egg.) Flaxseed contains long polysaccharides that help bind other ingredients together, and enough proteins to decompose and cause browning on the outside of a baked good as it cooks. But flaxseed meal isn’t nearly as smooth as egg, so don’t expect a meringue or delicate sugar cookie without visible pockets of flax.
If you need to replicate the structure-giving proteins of an egg, you can try applesauce (about a third of a cup per egg). It contains a lot of the compound pectin, which, in nature, helps solidify the cell walls in fruits (and also helps form the gels that hold jam together). But note that applesauce doesn’t have any fat in it to lend what Bouzari refers to as lubricity, or the sensation of moisture, so your pastries or breads might seem drier.
Keep in mind that no substitute will replace all of an egg’s properties. You just have to figure out the most important role that the egg is playing in a recipe to know which substitute might work best.
Like your cookies crispy or chewy? The kind of sugar you use makes a difference. If you like sinking your teeth into cookies and your recipe calls for corn syrup, you can try honey, molasses, or even pomegranate syrup to vary taste and keep that soft texture.
Corn syrup is “basically pure glucose,” says Bouzari, “which binds [to] water very well.” As a result, water can’t evaporate too quickly—and the more tightly water is bound, the softer the cookie will stay. “For your enjoyment of moist, fudgy cookies, you want that water to stay around,” says Bouzari. The other substitutes on this list are full of glucose or fructose, which also fixes water in place.
On the other hand, if you want cookies that snap when you bite and your recipe calls for regular table sugar, or sucrose, you can try a twist and use maple syrup instead. Maple syrup is made of mostly sucrose, which doesn’t bind that well to water. When dough made with maple syrup is heated up in the oven, the water tends to evaporate, leaving a drier product. “The water gets super excited and wants to get the heck out,” says Bouzari.
SciFri also asked YOU for your cookie recipe secrets. Here's what you shared: