It is often said that baking is half art and half science. In comparison to other types of cooking, a slight mistake in ingredient, temperature or technique can have a significant effect on the end result. Knowing the science of baking can help you predict what will happen, fix mistakes and alter recipes with confidence. With science you don’t have to cross your fingers and hope for the best every time you try something new.
Understanding the chemistry behind dough rise, cookie spread, cake tenderness, and crust crunch allows you to manipulate it to produce what you want. It helps you predict what’s going to happen when you make changes. It makes baking more of a science and less of an art.
Ingredients: Flour and Gluten Formation
Flour is a key ingredient in baked products, as it provides structure through the creation of gluten. Gluten is formed when the water in a dough or batter mixes with the proteins present in the flour, ultimately leading to the formation of an elastic web that holds in gases and creates the structure that gives rise to a product.
All-purpose and bread flours have a high protein content which means they will develop into a solid gluten. This is what you want for breads that need to be chewy.
Pastry flour (low protein) is perfect for cookies and cakes.
Unlike other ingredients, mixing flour too much develops the gluten, which can make baked goods tough, and not enough can make them crumbly and flaky.
Knowing how different types of flour act makes it easier for bakers to choose the type of flour that will give them the texture they want.
Texture and Fat Content
The role of fat. Fat contributes to tenderness, flakiness, and the ability of a product to retain moisture. When you add butter, oil, or shortening to a mixture, the fat surrounds the flour particles. This prevents them from forming gluten and results in a tender final product.
It’s because solid fats form layers (such as when you make a flaky pie crust or puff pastry), which makes the pastry flaky.
Liquid fats are completely absorbed by the batter, creating a uniform crumb texture and mouthfeel.
Keeping your fat cold, for instance, is what will help make your pastry flaky, but if you’re using it in a cake batter, you want it to be at room temperature so it will aerate when you beat it with your sugar.
Sugar has a bit of a double identity.
Of course, sugar makes things sweet, but it’s also involved in browning, texture, moisture, and color. It reacts with proteins to make the caramelization and Maillard reaction, which give your foods color and a lot of flavor.
Overload with sugar and the thing collapses or flattens.
If there is too little sugar, the finished products will be dry and dense.
Sugar also plays a role in fermentation: it softens the gluten strands and decreases the gelation of starch.
The Importance of Eggs
Eggs contribute structure, leavening, fat and moisture.
Beaten eggs provide the air for sponge cakes.
Egg yolks contribute fat and emulsification for smooth batters.
Whole eggs provide structure and flavor balance.
Proper egg treatment is important. Overbeating, as well as underbeating, can have an impact on texture and volume.
Baking Powder Baking powder can be found in many baked goods, including quick breads, cakes, and biscuits. This leavening agent releases carbon dioxide bubbles, making the dough or batter rise. Depending on the type, you can replace 1 teaspoon of baking powder with 1 1/2 teaspoons of baking soda plus 1/2 teaspoon of cream of tartar or 1/2 teaspoon of lemon juice or vinegar. Baking Soda Commonly used in recipes for cookies, bread, and pancakes, baking soda is another type of leavening agent that helps food items rise. For every 1 teaspoon of baking soda called for, you can use 1 teaspoon of baking powder or 1 teaspoon of potassium bitartrate. Natural Yeast You can also try using natural yeast as a leavening agent. It will help your baked goods ferment, but keep in mind that the taste and texture may differ from the original recipe.
Leavening agents release a gas that causes your baked good to rise in the oven. There are three primary leavening agents:
Baking soda or baking powder: These chemical leaveners also generate carbon dioxide and are often used in cookies and quick breads.
BIOLOGICAL LEAVENING: Yeast converts sugars into carbon dioxide and alcohol, giving flavor and creating rising bread.
Baking or mechanical leavening: The air beaten in by the creaming and whisking of the butter and sugar, and the folding of eggs, causes cakes, meringues etc. to rise.
Time, temperature and proportions are important to manipulate those reactions.
The Science of Heat
Conduction, Convection, and Radiation
There are various methods of heat transfer that impact how things bake.
Conduction: This is the transfer of heat from the pan to the food. This is important to toast the bottom crust.
Convection uses hot air circulation to provide even cooking and can reduce baking times.
Radiation: heat from the walls of the oven or broiler that browns and caramelizes the surface.
Knowing the flow of heat in the oven will help you change the positions of the racks, determine how long to preheat, and prevent hotspots.
Managing the temperature
The temperature of the oven will influence the texture, rising and the crust of the bread.
Too high: the food will brown too quickly before the inside is done.
Under-proofed: not enough rise, pale in color and heavy.
It’s important to use an oven thermometer to ensure that the temperature is accurate.
Even the temperature of ingredients affects the final product: the effect of cold butter compared to melted butter in cookies, and of room temperature versus cold eggs in cakes and cookies.
The Chemistry of Mixing Creaming and Aeration
When you cream together sugar and fat, you’re catching little pockets of air that are then released in the oven to aerate your cake. This is why you need to keep the air bubbles intact and evenly distributed.
Folding and Incorporating
Folding maintains aeration. With sponge and chiffon batters, overmixing will deflate them completely, resulting in dense, fallen cakes.
Managing Gluten Development
This is done by manipulating the mixing techniques: kneading for a long time and allowing the dough to rest to develop the gluten for bread, mixing as little as possible and using lots of fat to prevent gluten from forming for a cake, etc.
Moisture, Steam, and Humidity
Role of Water and Liquids
Liquid helps to activate the gluten, dissolves the sugar and salt, and helps the chemical reactions. Too much liquid makes the dough too runny, and too little makes the dough too dry.
Steaming to Leaven
The third role of steam is to assist in expanding or “puffing” baked goods such as laminated doughs, puffed pastries, and some types of bread. In these cases, adequate moisture content and temperature in the oven are critical.
Humidity
Flour absorbs more or less liquid depending on the relative humidity of the air. So if you’re in a very humid climate you may need less liquid in your doughs and if you’re in a very dry climate you may need more. This is useful to know if you’re having trouble getting the right texture.
B. Color and Flavor Development: Maillard Reaction and Caramelization
The Maillard Reaction: The browning of protein and sugar when heated that results in the development of savory and sweet flavor compounds.
Caramelization: This is the browning and flavor that comes from sugar being heated past its melting point.
They are both temperature dependent and affect crust, aroma, and flavor. Managing these processes is what creates professional products and flavor.