Have you ever seen a baked good rising in the oven? It’s a fascinating thing to see. If you have a curious mind like mine, you must have definitely wondered how that happens. Well, I’m here to tell you exactly how it happens.
It’s magic. Not just any magic; it’s the magic of the leavening agents. Despite the fact that they sound like a team of avengers (which, to be honest, they really are), leaving agents are techniques and ingredients that trap gasses in a baked good and help it rise to become airy and fluffy. Leavening, i.e., trapping gasses in a baked product, can be done through various ingredients like baking powder, baking soda, and yeast, and techniques like whipping, creaming, and folding.
Every single baked good uses at least one type of leavening ingredient or technique. Bread uses yeast; cookies use creaming and baking powder, and cakes use baking powder and baking soda. In other words, baking cannot be done without leavening agents, and understanding how they work can make a huge difference in your final baked product.
Today, we’ll be taking an in-depth look into the science of leavening agents in baking – how they work and react with different ingredients to help you better understand the processes and give you the ability to develop your own recipes.
Welcome to Ep 4 of Baking Basics, a series where we will dive deep into the science of baking’s 4 key ingredients – eggs, sugar, butter, and raising agents- to help you develop your recipes and troubleshoot baking errors, and become a better baker.
Check out the previous episodes here.
- Episode 1: Baking Basics – Eggs In Baking
- Episode 2: Baking Basics – Butter In Baking
- Episode 3: Baking Basics – Sugar in Baking
Types of Leavening Agents
As I mentioned earlier, there are a few different types of leavening agents in baking, some more effective than others, each different in its own way. Let’s take a look at the different types.
Chemical leavening agents
Chemical leavening agents like baking soda, baking powder, and cream of tartare undertake a chemical reaction that releases gas into the baked goods, leading to the leavening process. This happens when an acid is mixed with a base which leads to the formation of bubbles in the batter, helping the baked good rise. Let’s look at the three main chemical leavening agents in baking.
- Baking soda – Also known as sodium bicarbonate, baking soda is an alkaline salt (i. e. it is a base) that contains oxygen, carbon, sodium, and hydrogen. When this base ingredient is mixed with an acid (for instance, lemon juice, yogurt, or vinegar), it releases carbon dioxide air bubbles, enabling baked goods to rise and expand. Because it is a base, baking soda requires an acid to activate its leaving capabilities.
- Cream of Tartar. – In contrast, cream of tartar, also known as potassium bitrate, is acidic in nature and requires a base like baking soda to activate and help baked goods rise.
- Baking powder – Baking powder is a combination of baking soda with an acid, which means that it does require any activation and can be used as is for leavening. Once the baking soda is mixed with a wet ingredient, it activates immediately and releases gas into the batter.
Biological Leavening Agents
While chemical agents are manufactured, biological agents are made of natural microorganisms that enable the fermentation and gas-release process in baking when activated and help baked goods rise. The most popular biological leavening agent is yeast, which is made of fungi. Yeast, which is primarily used in bread and doughs, breaks down sugar and starches and produces carbon dioxide bubbles, flavor compounds, and even alcohol (if fermented for very long) which gives bread its fluffy and airy texture.
However, the speed at which carbon dioxide is released using yeast is not as quick as that of chemical leavening agents, which is why a dough using yeast must have a properly developed gluten structure to trap the gasses for a long time. If you remember, in lesson 3, we spoke about delaying gluten formation in baked goods like cakes and cookies; the more gluten a batter has, the more firm it will be. This means that such batters don’t have a strong gluten structure and, therefore, cannot be leavened properly using yeast.
There are three commonly used types of yeast; let’s look at each of them in-depth.
- Active Dry Yeast – The most common household yeast, active dry yeast, is created by drying fresh yeast and sold as a powder. This type of yeast has to be activated in warm milk/water and sugar before being added to the dough. You will know that the yeast is activated when the mixture rises and forms small bubbles on top in 10-15 minutes. If it fails to do so, it indicates that your yeast is dead and will not work.
- Instant Dry Yeast – In contrast, instant dry yeast, as the name indicates, can be used instantly and does not require any activation or proofing.
- Fresh Yeast – This is yeast in its true form and is sold in compressed vacuum packets. Fresh yeast is most commonly used in bakeries and is active only for a few days, up to a week. This type of yeast can be added directly to the dough.
How to find out if your yeast has died: If the yeast has been on the shelf for a long time, there is a chance that it has died and will not work. The only trick to finding out if it’s still alive is trying to activate it by mixing it with water and sugar. Let the mixture proof for 10-15 minutes. If it starts rising and forming bubbles on the surface, it means that the yeast is still active. If it’s unchanged, it means that the yeast is dead and needs to be replaced.
Physical Leavening Agents
Physical leavening agents are the techniques and manual processes that introduce air into a batter, allowing baked goods to expand while baking. This process occurs when ingredients are mixed vigorously, creating air pockets in the batter which rise in the oven and gives baked goods their fluffy, airy texture.
Here are the three main types of physical leavening processes.
- Whisking – When stable ingredients like eggs are whisked together rapidly with an electric beater or hand whisk, the process introduces air bubbles which are then trapped in the molecules which are stable enough to trap and hold the air, resulting in a rise while baking.
- Creaming – Creaming is the process of beating room-temperature butter with sugar. If you can recall from lesson 2, when butter and sugar are mixed together at high speed, it creates air pockets that remain trapped due to the stable nature of butter. This process leads to leavening as the air in the butter expands while baking, helping the baked good rise.
- Steam – Every dough and batter contains hydration and liquid in some form. While baking, this liquid evaporates, creating steam that expands and helps baked goods rise. Many pastries like puff pastry and choux buns rely solely on steam for leavening; the rise comes from the liquid evaporating from the air pockets.
The Most Important Tip For Using Baking Leaveners
When using chemical or biological leavening ingredients, it’s important to ensure that they are fresh and not stale. As all these ingredients are acidic, chemical, or biological, they have an expiry date. Too long on the shelf, and they lose all their leavening capabilities. Here is how you can check if your learners are working.
- Baking soda – add a splash of acid (like vinegar or lemon juice) to the baking soda. If it sizzles and froths up, the baking soda is active and reacts with acid. If it does not sizzle, it needs to be replaced.
- Baking powder – unfortunately, the only way to check if your baking powder is active is to test it in a baked good. If you end up with a flat, dense product, your baking powder has to be replaced.
- Yeast – yeast can be tested by mixing with water and sugar. If the mixture starts to rise and becomes frothy after a few minutes, the yeast is alive and ready to be used.
Baking Leaveners – Summary
- Leavening is the process of introducing air and gas into baking batters and dough to give them the capability to rise and become airy and fluffy.
- There are three types of leavening agents – chemical, biological, and physical.
- Chemical leavening agents like baking soda, baking powder, or cream of tartare release carbon dioxide into a batter with the help of an acid and base reaction.
- Biological leavening agents like yeast are made with live microorganisms that release gas into doughs when activated.
- Physical leavening agents are techniques and processes like whisking and creaming that introduce air into a batter with the help of manual labor.
- Use fresh leavening agents to ensure that they are still active and have not gone stale.
And there you go, you are now fully educated about the science of leavening in baking. With this information, you can figure out how to use these leavening agents when developing your own recipes or troubleshoot when things go wrong.
I hope you found this series helpful! I learned a lot throughout my research journey, and I am so excited for all of you to learn it with me!
If you have any other baking questions, drop them in the comments!
Until next time!
