One of the questions we’re asked most often, and think about ourselves when posting recipes and advice, is why certain ingredients are included in baking recipes and what is their purpose. For example, whenever you look up a baking recipe, you’ll be confronted with the common list of ingredients including flour, eggs, butter, and sugar. Buy a cookbook and you’ll always find these at the front. They’re your baking essentials, without them you have no cakes, cookies, or anything else.
Let’s get scientific; what do these ingredients really do?
Any parents who love to bake will be conscious of how much sugar they’re putting into their recipes, especially if they’ve had a bad experience in the past of having their kids crawling the walls after eating a piece of cake. However, sugar plays a role for far more than sweetening reasons.
Without sugar, flour proteins can join in the baking process and make gluten. This is why you’ll often find many gluten free foods that have a higher than normal sugar content. This same factor is why you can usually find ingredients labelled as “low fat” but with high sugar content. When there’s sugar in a recipe, the flour joins with this rather than itself.
As for the sweetening that sugar brings, this is as a result of the sugar caramelizing. To get really scientific, certain sugars are better at absorbing moisture than others, which is why biscuits made with brown sugar stay softer and moister than those made with white sugar, for example.
What do Butter and Eggs Do?
We’ll cover eggs first, as you have probably found yourself asking why certain recipes require egg yolks, while others will specify egg whites, while others simply say to use the eggs as whole.
- Egg whites are a drying agent; check out a meringue recipe to see how important egg whites are and the difference they make.
- Egg yolks help to give a mixture a rich, creamy texture.
These properties are why you should be careful when using “ready-made” cake mixture or egg substitutes; it is actually very difficult to replicate the properties of eggs! Try making a delicious custard with an egg substitute, and you’ll see what we mean!
Butter is the ingredient that does the most multi-tasking in baking; it carries and holds flavors, makes recipes feel lighter by holding air bubbles within the mixture, and tenderize the finished product as it covers proteins in the flour. Butter is always better than margarine, so use it all the time unless a specific recipe calls for the latter.
Why is Salt Important?
Salt is very important in the science of baking and does so much more than just contributing to the flavor. Salt helps preserve the color and flavor of flour. It also strengthens the gluten protein in dough and is necessary for bread, as it controls the fermentation rate of yeast. Did you know that without salt, holes with form in your bread? The bread rises faster and air pockets enlarge where the gluten has broken. Bread made without salt will taste bland. Salt also indirectly contributes to crust coloring. Without salt, the yeast quickly consumes the available sugars, and the crust on the baked bread is pale and dull.
Baking Soda vs. Baking Powder
While baking soda and baking powder are leavening agents they are used in different situations. They are added to produce carbon dioxide so baked goods will rise. Baking soda is pure sodium bicarbonate while baking powder includes cream of tartar (an acidifying agent), and starch (a drying agent). Which is used will depend on the other ingredients.
It is important that when you use only pure baking soda, you bake your goods immediately because a chemical reaction (bubbles) occurs and they will expand upon baking. Wait too long and your goods will be flat. Recipes that call for only baking soda will have some kind of acidic ingredient such as honey, chocolate or yogurt.
Baking powder on the other hand has a built in acidic ingredient. As long as you are using a double-acting powder, your mixture can sit a while before baking and be fine because they react in two phases and the gas won’t be released until baked.
Note that you can substitute baking powder for baking soda in a slightly higher amount the the recipe calls for, but you can not substitute baking soda for baking powder.
Do I Really Need to Measure Flour?
We’re moving from a science to a math lesson here! Where many bakers go wrong is by assuming that the volumes featured in recipes are there as a rough guide, and not as a “must follow.” But baking is a science, and certain ingredients need an exact measurement.
Admittedly, you can get away with a little too much flavoring, for example, but when you start messing around with measures of certain ingredients such as flour, sugar, eggs, baking soda or salt, and you may be asking for trouble. Flour is usually the biggest problem, as it can be thrown into recipes lumpy and is often crudely added without the necessary care and consideration.
Ensure you spoon flour gently into your measuring cup to get the exact amount of flour you need; any other method could end in disaster!
Getting the wrong volume of flour in your recipe can lead to the texture of your baked goods being all wrong, and because it will affect the baking time, you could also find yourself with a burnt or undercooked final product. As you won’t have made allowances for the other ingredients to be in proportion with the flour, you will either end up with a complete mess, or start adding more ingredients to try and counteract this, and might end up having to throw everything away and starting again!
Even if you’re not scientific, understanding the science of baking will help you to create the best possible recipes and ensure you don’t mindlessly substitute ingredients thinking it doesn’t matter. Have fun putting your new scientific knowledge to the test!
This article was written in conjuction with Robert Gray of Bradford’s Bakers, and independent bakers and confectioners based in Glasgow, Scotland.