When we divorce ourselves from wheat, we lose the gluten that, when combined with yeast, generate the “rise” that gives wheat bread that light and airy texture. It means that we often struggle to create non-wheat breads that are big enough to make sandwich breads.
The rise generated by yeast just means that carbon dioxide (CO2) was generated by the metabolism of carbohydrates (amylopectin and amylose) by yeast. We can also generate CO2 by other means, called “chemical leavening.” (Frankly, I don’t like that term because it sounds like we are doing nasty, chemical things but, as you will see, the reactions to generate CO2 are quite natural and safe.) Most forms of chemical leavening involve the generation of CO2 by reacting an acid with a base. There’s also the process of “mechanical leavening,” using some physical or mechanical means of incorporating air into the mix; whipping with a power or hand mixer is one example.
Here are the methods that I have found helpful in helping to generate rise in wheat-free baking:
Use acid-base reactions–An easy way to remember this if, for instance, you are experimenting with a new recipe, is to mix your base–baking soda, or sodium bicarbonate–into your dry mix (e.g., almond meal/flour, coconut flour, ground golden flaxseed); mix your acid–citric acid, lemon or lime juice, or vinegar–into your liquid mix (e.g., egg yolks, coconut milk, water). When you combine dry and liquid mixes, you will see a foaming reaction, representing the reaction of acid with base that generates CO2. Typical proportions to use are:
1 teaspoon baking soda: 1/4 teaspoon citric acid
1 teaspoon baking soda: juice of 1/4-1/2 lemon
1 teaspoon baking soda: 2 teaspoons vinegar
You can even do this more than once. For instance, let’s say you are using lemon juice. Start with a little extra (e.g., 1/2 more teaspoon) baking soda in your dry mix. Proceed with making your wet mix using lemon juice, reserving a bit. Mix wet into dry, then proceed with adding your egg whites (see below). Then add the remaining lemon juice, again causing the foaming CO2-generating reaction to occur.
Whip egg whites–Whipping egg whites with cream of tartar (potassium hydrogen tartrate, used in winemaking) helps stabilize the whipped whites. Use 1/4 teaspoon of cream of tartar per 2 egg whites; whip at high-speed until peaks form. This represents a modification of mechanical leavening. It is usually best to add the egg whites after the acid-base step (above) is completed over 1-2 minutes; this avoids the peculiar ammonia-like smell of “Baker’s ammonia,” the product of a reaction between baking soda and the proteins in egg whites.
Microwaving–If you are using a microwave-safe baking dish, you can increase risk considerably (typically 30% increased volume) by microwaving for 1-2 minutes. The amount of time will vary, depending on the size of dish, the depth of the dough, and the ingredients, so a bit of experimentation may be necessary to generate maximum rise. I usually microwave in 30-second increments. (Yeah, yeah, yeah: I know all about the objections some people raise to the use of a microwave!)
I will often use all three methods, including the two-stage acid-base step, to generate plenty of rise when I want it, e.g., for greater rise for a sandwich bread or a fluffier cake. It’s not perfect, but you still can obtain some very nice results using these techniques.
And I’d love to hear whether any of you clever wheat-free bakers have come up with any of your own methods!