LEAVENING AGENTS

LEAVENING is the production or the incorporation of gases in a baked product to increase volume and to produce shape and texture. These gases must be retained in the product until the structure is set enough (by the coagulation of gluten and egg protein) to hold its shape.Exact measurement of leavening agents is important

YEASTFERMENTATION is the process by which yeast acts as on carbohydrates and changes them into carbon dioxide gas and alcohol. This release of gas produces the leavening action in yeast products. The alcohol evaporates completely during and immediately after baking.

YEAST

34F(1C)- inactive, storage temperature60-70F(15-20C) slow action 70-90F(20-32C) best growth, proofing temp for bread doughs100F(38C) reaction slows140F(60C) yeast is killed

THREE FORMS OF YEASTFresh YeastActive dry yeastInstant dry yeast

Fresh yeast active dry yeast x the quantity by 0.5Fresh yeast instant dry yeast x the quantity by0.35

CHEMICAL LEAVENERSBaking Soda

Baking Powder- Single acting baking powder- Double acting baking powder

Baking Ammonia

AIRAir is incorporated into a batter primarily by two methods, creaming and foaming. This air expands during baking and leavens the product.

CREAMING

FOAMING

STEAMWhen water turns to steam, it expands to 1,600 times its original volume. Because all baked products contains some moisture, steam is an important leavening agent.Puff pastry, cream puffs, popovers, and pie crustsIf the starting baking temp for these products is high, steam is produced rapidly and leavening is greatest.

STEAM BAKING