Basic Pastry Making-Leavener
Leaveners make your baked goods rise. Heard of unleavened bread? It's flat--no leavening. You have to use some sort of leavening if you want something fluffier and lighter than matzo.
Leaveners fall into a three different categories that I will label biological, chemical and mechanical.
Biological Leaveners: We're talking yeast here. Yeast are little one-celled organisms that do two things: they eat sugar, and they turn it into alcohol and carbon dioxide. Yeast is used in beer and bread production, and often beer is referred to as "liquid bread."
Anyway, in bread making, the carbon dioxide bubbles are trapped in the gluten strands (see the module on "Flour"), and that's what makes the bread rise.
Chemical leaveners: ingredients that give off carbon dioxide when in the presence of liquid. Baking soda is one of these leaveners, and baking soda is also the reason that Alka Seltzer bubbles. All that "Plop, plop; fizz, fizz" is put to great use leavening slightly acidic ingredients (think buttemilk, natural cocoa powder and molasses).
Baking powder is baking soda to which an acid has been added. This leaves the pH of the powder at 7, or neutral. Baking powder is used to leaven neutral batters, or batters that don't contain acidic ingredients.
Double acting baking powder has two chemical reactions. It releases some carbon dioxide bubbles when it gets wet (during initial mixing), and it emits more carbon dioxide bubbles when it's exposed to heat (in the oven). Using double acting baking powder can result in a higher and more even rise.
Mechanical leaveners: Eggs and steam. Baked goods that are leavened mechanically rise because a)you've either beaten enough air into egg whites or whole eggs (think angel food cake or genoise) that the air in all those millions of foamy egg bubbles will expand in the oven and make your cake rise, or b) there's enough water in the batter that will turn to steam and force a rise (think cream puffs and puff pastry).
And that is the lesson on leavening.
Source: Notes & pictures from Google
Comments
Post a Comment