1. Warm Up Why do bread, cakes and baked goods rise?

2. Leavening Agents Chapter 21

3. What is Leavening To Leaven means to lighten Bubbles of gas cause the mixture to inflate Main gasses that leaven are: Air, Carbon Dioxide and Steam Air and steam naturally occur and Carbon dioxide is produced by chemicals

4. Air Not the main leavening agent in most baked goods Principle leavening agent in meringues and angel food cake –Products based on egg foam –Beating eggs incorporates air into the batter Mixed through many means –Sifting flour, beat fat with sugar and whipping batter

5. Steam Water in the liquid produces steam Recipes that use steam to leaven require very hot ovens Eggs and Gluten provide the structure of steam leavened products Steam forms and the batter forms around it

6. Using Carbon Dioxide to Leaven Two basic methods for creating Carbon Dioxide –Baking Soda or Baking Powder create a chemical reaction that yields gas –Using Yeast in a biological process to create the gas

7. CO 2 Chemically Two leavening agents: Baking Powder and Baking Soda They participate in a chemical reaction that produces CO2

8. Baking Soda The chemical compound sodium bicarbonate Releases sodium carbonate and carbon dioxide when heated sodium bicarbonate gives bad taste and yellowish color to baked goods Always used with an acid to prevent sodium carbonate from forming –Buttermilk, vinegar, lemon juice, molasses, honey, fruit, fruit juices and cream of tartar

9. Baking Powder Leavening compound that contains baking soda, dry acids and starch or some other filler The filler helps absorb moisture in the air, which prevents the chemical reaction from taking place too fast You can make baking powder by combining: baking soda, cream of tartar and corn starch

10. Baking Powder Comes in two types: –Single Acting and Double acting –Double Acting: contains two acids-one that reacts with cold liquid and one that reacts with heat –Most of the carbon dioxide is produced when heated in the oven Preferred in the US –Single Acting: as soon as liquid is added carbon dioxide starts to be released Rarely sold in US

11. Power of Baking Powder By Federal Law: Baking Powder must yield 12g of carbon dioxide for every 100g of powder Most yield about 14% Baking Powder must be a least 25% baking soda by volume Too much baking powder causes flour mixtures to stretch too far and break and collapse Too Little will make a compact product If not stored in a tight container it can absorb moisture and react too early

12. Producing CO 2 w/Yeast Yeast: microscopic organism that produces carbon dioxide through fermentation –Fermentation: biological reaction that slowly splits complex organic compounds into simpler substances Yeast converts sugar to ethyl alcohol and carbon dioxide The alcohol evaporates and carbon dioxide causes the product to rise The yeast is killed by the high baking temperatures, which stops fermentation

13. Making Leavened Products Batters and Doughs Batters contain more liquid than doughs Pour Batters: made with equal ratio of flour to liquid (usually water). Range from thin to hard to pour. Pour batters are used to make waffles and pancakes Steam is the main leavening agent in pour batter used to make popovers and cream puffs

14. Drop Batters Muffins, quick bread loaves and some cookies Mix 2 parts flour to one part liquid Baking powder and steam are leavening agents in these recipes

15. Soft and Stiff Doughs Soft Dough –Mixing three parts flour to one part liquid –Need more mixing to develop gluten –Yeast breads, baking powder biscuits and pizza crusts are made from soft doughs Stiff Dough –Six to Eight times as much flour as liquid –Drier consistency –Pie crusts and some cookies

16. Yeast Products Yeast Bread is made from soft dough Yeast is sold in granular and compressed forms Pellet is stable at room temperature Compressed should be refrigerated or frozen Basic Ingredients include: Flour, Liquid, Salt, Sugar, Fat and Eggs

17. Purpose of Ingredients Flour: provides starch, proteins that form gluten, gives structure Liquid: Usually water or Milk. –Milk is often chosen because it adds ingredients and makes bread last longer. Steam from the liquid combines with the CO 2 produced by the yeast helps the bread rise. Salt: Adds Flavor. Prevents enzymes from breaking down proteins Sugar, Fat and Eggs: Sugar helps crust brown and adds flavor. Eggs make the bread richer in texture and flavor

18. Quick Breads Need no time to rise. These products are made with a leavening agent other than yeast. Usually steam or COs that is produced by baking soda or baking powder Muffins, Coffee Cakes, popovers and biscuits are examples All contain flour, liquid and salt Proper mixing is important Over stirring or mixing overdevelops the gluten producing a tough product

19. Leavened Cakes Leavening used affects the cakes texture Traditional cakes such as sheet cakes, and layered cakes are shortened cakes Contain fats ad chemical leavening agents Air is added when fat and sugar are beaten together or if the recipe calls for eggs to be beaten separately Fat and eggs tenderize the batter so it expands easily

20. Pound Cakes/Unshortened Cakes Pound Cakes: primarily leavened with air and steam –Air is incorporated when batter is mixed –Heat changes liquid into steam, the steam enlarges the air bubbles and causes the cake to rise Unshortened Cakes: include Sponge, Chiffon and Angel food cakes –Depends on the air beaten into an egg foam for leavening, Steam is also used –Angel food cakes expand more due to the amount of egg whites used –Eggs provide protein and contain water that converts to steam, creating a tall, light cake