Leaveners: Lighten Up

Oh heck yeah! When many of us think of Autumn we all think of school starting, baseball playoffs, football, and the start of another hockey season (I just had to throw that in there.). As for us cooks we also think of Fall as the beginning of baking season. The weather’s cooling off (FINALLY a little if you live here in Texas!), so the thought of having your oven on for an hour or two actually sounds okay, instead of like turning on furnace in your kitchen for a few hours.

And as home bakers, we have come to learn that an important element in baking is leavening. So I thought it might be informative to talk about leavening for a bit.

What the heck is "leavener" anyway?

We hear the term "leavener" all the time, so let’s begin by defining what it even means. When it comes to baking, the word “leaven” means to lighten dough or batter. It is accomplished in several ways typically using either biological or natural leaveners (like yeast) or chemical leaveners (like baking powder or baking soda).

They create “leavening gases” (ummm...actually carbon dioxide) which give baked foods their volume. They expand the air bubbles (and there are tons of them!) that have been put into the batter or dough by whipping, kneading. etc. The gluten structure traps them and the leavener enlarges them. Moisture and heat make this happen.

When carbon dioxide is released by either baking soda and/or baking powder, it first dissolves in the batter's liquid. When there's more carbon dioxide than the liquid can take in, the carbon dioxide begins to find its way into the air bubbles, which causes them to expand. The bubbles continue to expand as long as the batter is not fully baked. When the batter sets into a firm structure during baking (heat), the air bubbles stay around. These are the air bubbles (big or small) that you see in your finished baked goods.

In addition to texture, leaveners also contribute to baked goods' taste and color. For a successful recipe you want to balance the leavening system to achieve a neutral pH. Having an unbalanced pH can lead to the common problems we often see in baking - off-taste or color, not setting right, cracking, etc.

Chemical leaveners have only been around for about 200 years. Prior to that yeast was the prevalent leavener used. That's why most early baked goods were more flat (think totillas, naan, etc.).

There are so many names

Biologic or Natural Leaveners

  • Yeast: Yeast is the most commonly used leavener in bread baking. There are:
    • Commercial Yeast: Member of the Saccharomyces cerevisiae (go ahead, try to pronounce THAT!) species and is actually a member of the mushroom family.
    • Sourdough Starters or "wild" yeasts (and bacteria): Predominant yeast belongs to the Saccharomyces minor family, and is called Saccharomyces exiguus.

Chemical Leaveners

  • Baking soda: Sodium bicarbonate (or sodium acid carbonate), is a natural alkaline ingredient derived from trona ore. A finished product made with baking soda usually is associated with a slightly coarse or shaggy texture. It is a base and so it reacts with acids. (Remember that chemistry class? :) Baking soda begins to release carbon dioxide immediately after moistening and it needs an acid (like buttermilk, sour cream, brown sugar, vinegar, or citrus juice) to be activated. It is usually mixed in with the dry ingredients. Baking soda works by reacting with the naturally acidic ingredients in a dough or batter). It releases most of its gas immediately when combined with an acid and moisture, and a bit more when heated. 
  • Baking powder: I’ll dig a little bit deeply into baking powder since it’s probably used more often and is a little more involved. Think of baking powder as baking soda with the acid already added; along with an inert starch (i.e. corn starch) to act as a filler and prevent the components from reacting prematurely. Baking powder creates carbon dioxide bubbles when both moistened and heated.
    • Most baking powder on the market today is double-acting. It uses two acids to create reactions in two stages. One acid reacts very quickly and, when combined with a liquid starts to aerate the batter. The second acid is slower-acting, and begins to release carbon dioxide only when heated.
    • This double-action is a real advantage. It allows you to make recipe in advance since the second-stage doesn't kick in until it's heated. And the acid/baking soda is in balance, so you don;t have to worry about that part of a recipe. An imbalance of acid and baking soda can cause a kind of "soapy" aftertaste.
  • Baker's Ammonia (ammonium carbonate or ammonium bicarbonate ): Ammonia?!?! Don't worry. This is NOT the same as ordinary household ammonia, which is poisonous.  It’s a type of baking powder that yields a very light, airy product, but can impart an ammonia flavor to baked goods. It's best used in cookies, which are flat enough to allow all of the ammonia odor to dissipate during cooking. It’s not used very much in the U.S.
  • Cream of Tartar: This is a natural fruit acid that actually comes from the winemaking process. It accumulates on the inside of wine casks as the wine matures and then gets scraped out of the barrels. How cool is that? It's one of the ingredients that, along with baking soda, goes into baking powder. Cream of tartar is often used to stabilize meringue, as its acid helps strengthen the proteins in the egg white, allowing them to trap more air as they're beaten.

Often overlooked are the other, more mechanical means of leavening. But they too are important. So, don’t overlook them. And certainly don't skip or short-change them if your recipe calls for it. The key is that they add air into the mixture. Some examples of these are beating sugar, butter and eggs into a light and creamy mixture to include in the dough or batter, whipping or beating air into the eggs or egg whites, or fluffing flour before sprinkling into the measuring cup. These can make a difference in how your baked goods set up.

So, what’s important to know about leveners?

The type, amount, and balance of leavener can be the difference between a nice, light fluffy cake or bread and the flat, hard disk we’ve all probably experienced at one time or another. Generally, just follow the recipe you are using. Some other tips:

  • The general rule is to use 1 to 1-1/4 teaspoons baking powder per cup of flour. On the other hand, baking soda should be added at 1/4 teaspoon per cup of flour.
  • Try to get a baking soda dough into the oven as quickly as you can, as it begins losing its leavening ability as soon as it's mixed.
  • If your cake dips slightly, it has too much leavening, so reduce the baking powder by 1/4 teaspoon. If you are using baking soda, decrease it by 1/16 teaspoon. If the cake domes, do the opposite - increase the baking powder by 1/4 teaspoon or the baking soda by 1/16

Showing off a little

So what are a few things that you can use to impress your friends? Well, try these!

  • You can make your own baking powder. Mix 1 part cornstarch, 1 part baking soda, and 2 parts cream of tartar. 
  • Baking soda is four times as strong as baking powder.
  • You can substitute baking powder for baking soda. Just know that if the recipe calls for an acid (which it will) the final result could have a slightly acidic taste. If that’s what you want, go for it.
    • As an example, if you like the slightly acidic flavor of buttermilk, and your recipe calls for baking soda to neutralize it, try using baking powder instead, which will allow the flavor of the buttermilk to be more assertive.
  • Chemical leavers have only been around since about 1800. Before that it was yeast all the way! All the way back to the ancient Egyptians about 5,000 years ago! 

I tried to keep the info here helpful, but light (pun completely intended!). If you want to dive even deeper I can share some great resources with you. Just leave me a comment. Now, go bake something great!!