Understanding How Steam Works

• Unlike yeast or chemical leaveners such as baking soda or baking powder, steam leavens baked goods using the moisture that's already present in the wet ingredients. Often referred to as a physical leavener, steam works powerfully, expanding to take up approximately 1,600 times as much space as water. As the liquid, which comes from water, eggs, milk, syrups or other wet ingredients, in your dough or batter gets heated in the oven, it transforms into its gaseous state. As the steam is released, it presses into the pockets of air, causing the dough or batter to expand and rise. Steam leavening is particularly effective at temperatures of 400 degrees Fahrenheit or greater since higher temperatures give you a higher volume of steam.

Steam Leavens All Baked Goods

• To a certain extent, all baked goods rely to some degree on steam for leavening since all baked goods are made with wet ingredients. However some baked goods rely more heavily upon steam than others. For example, although the air that’s whipped into egg whites acts as the main leavener in angel food cake, steam plays an equally important role since it helps amplify the air’s lifting power. Steam is created as the eggs whites are heated, and it helps give you the light, spongy consistency that’s characteristic of the dessert.

Baked Goods That Use Steam as the Main Leavener

• Although everything needs some steam for leavening, there are a few baked goods that rely almost solely on steam as their leavener. Some examples include cream puffs, popovers and puff pastry. Cream puffs and popovers both rely on steam to rapidly leaven the dough, creating an outer crust with a hollow center. Puff pastry works a little differently since it's made by stacking flour and fat to create layers of air pockets. These pockets then expand as steam is released in the oven, giving you that mile-high lift that's characteristic of puff pastry.

Tips for Leavening With Steam

• If you want to maximize the effects of steam on your batter or dough, one of the best ways is to work the dough a bit more to introduce more air. Some of the methods for getting more air into the mix include creaming sugar and butter together, whipping eggs, kneading dough and fluffing the flour with a fork or a whisk before you measure it. This also strengthens the structure of the dough while increasing its elasticity to let the air pockets expand effectively. Another way to boost steam's effect is to add another leavener such as baking soda or yeast to increase the gases released into the baked good, giving it a lighter texture.