Must-Know Baking Tips for Quick Breads, Yeast Breads, and More

Have you ever tried your hand at baking a loaf of homemade bread? If so, you may have wondered if the baking process is considered a chemical change. After all, it does involve combining ingredients like flour and yeast to create something entirely new. Let’s take a look at what happens when we bake bread to answer this question.

  • What Is a Chemical Change?
  • Is Baking Bread A Chemical Change?
  • FAQs
  • Conclusion

Before we can say for sure whether or not baking bread is a chemical change, it’s important to understand exactly what constitutes a chemical change.

A chemical change occurs when two substances combine to form an entirely different substance. This means that the original substances are transformed into something completely new with distinct properties.

Is Baking Bread A Chemical Change?

Yes, bread-making involves combining several ingredients—flour, water, salt, yeast—which means that it has the potential to be considered a chemical change.

During the kneading process, gluten molecules in the flour react with water molecules and become linked together, creating long protein chains called gluten strands.

As more water is added during kneading, these gluten strands become even longer and more elastic and trap carbon dioxide gas bubbles released by the yeast during fermentation.

In other words, something completely new has been created—a doughy mass that behaves differently than any of its individual components did on their own!

The baking process is when things really get interesting because heat energy triggers various physical and chemical reactions at once. On one hand, the heat dries out some of the dough’s liquid content while simultaneously breaking down starch molecules into simple sugars (which gives baked goods their sweet flavor).

On the other hand, proteins and carbohydrates in the dough undergo Maillard reactions which give bread its characteristic golden-brown exterior crust and nutty aroma—all of these changes occur as part of one single reaction!


Souring milk is a classic example of a chemical change that takes place through the process of fermentation.

During this process, bacteria convert the natural sugars in milk into lactic acid, which causes the sour flavor and thick texture associated with soured milk.

It is also possible to add special cultures to fresh milk to cause this reaction more quickly. While this process is a chemical change, it can also be reversed by boiling the milk to kill off the bacteria. The sour taste will disappear, leaving behind fresh milk once again.

In summary, soured milk is a result of a chemical reaction and can be reversed through heating.

Although it may not look like much has changed in the milk, a chemical reaction has taken place to cause this change in taste and texture. This is why soured milk is considered a classic example of a chemical change.

Understanding the science behind this process can help us appreciate how complex and dynamic the natural world truly is.

Ultimately, understanding the chemical changes that take place when milk sours can help us understand the chemical changes taking place in other parts of the natural world. From food production to biotechnology, chemical reactions are at the heart of many processes that make life possible on Earth.

By understanding these chemical changes and their implications, we can work towards protecting our planet for future generations.

Is cooking an egg a chemical change?

Cooking an egg is considered a chemical change because it involves the rearrangement of molecules.

When you cook an egg, heat causes the proteins in the egg to break down and form new compounds.

This type of reaction is called denaturation, and it can’t be reversed—the original molecules are permanently changed. It’s a similar process to when you combine certain chemicals together to form new compounds. That’s why cooking an egg is thought of as a chemical change.

There are other clues that this is a chemical reaction, too: it involves changes in color and texture, and there are often gases released or absorbed during the process.

All these factors together make it clear that cooking an egg is a chemical change.


So there you have it — baking bread does indeed constitute a chemical change! By combining several different ingredients together in just the right way under specific conditions (heat), you can end up with something entirely different from any of its constituent parts alone — making it an excellent example of how chemistry works in our everyday lives! Whether you’re an experienced baker or just getting started on your journey toward becoming one, understanding how chemistry plays into bread-making can help you perfect your recipes even further. Give it a try today!

This story is as old as the stalest bread, which is to say at least 14,000 years. The act of mixing flour with water, raising it with a leavener, and baking it goes back at least that far. The process is deeply familiar, yet most of us don’t know much about what is happening down in that mass of dough. Let me tell you, it’s complicated.

The science of doughs and batters can fill books upon books and still not cover all there is to know about how it works. So a relatively brief article like this one that’s focused on just one facet of a much larger story is guaranteed to have holes in it, which is fitting, because the subject here is exactly that—the bubbly spaces that inflate breads, cakes, and countless other leavened baked goods. Without the bubbles that aerate them, breads would be rock-hard lumps that we’d have to suck on in hopes of dissolving a bit with our saliva, and cakes would be dense and rubbery discs that might work best as drain stoppers.

Serious Eats Video Team

Ask people how air bubbles form in doughs and batters, and they’d likely say that yeast or a chemical leavener like baking soda produce gas bubbles that provide aeration. And they’d be partly correct, but the full story is more complicated—and more interesting. Why exactly do cakes have such fine, tiny bubbles while breads can have huge hollows in them? It’s not an easy question to answer, as doughs and batters are incredibly complex systems.

The importance of bubbles, though, isn’t just about the bubbles themselves, it’s about what they make possible. Only through an elaborate dance of a multitude of chemical and physical processes can a loaf of bread or moist cake exist. Understanding this science will not automatically make you a better baker (though it certainly can!), but it will help you understand why so many baking recipes work the way they do.

I want to take you on a journey to witness firsthand the lifecycle of bubbles in doughs and batters. To do it, we’re gonna fire up the miniaturization-laser of our imaginations and shrink ourselves down, Honey-I-Shrunk-the-Kids-style, to visualize the bizarro world of bubbles firsthand.

But First, What Are Batters and Doughs, Anyway?

Doughs, as you’ve probably noticed, are drier than batters. Doughs may be sticky, and they’re very much malleable, but batters are far more wet and flowing. This is because doughs have more flour than water, while batters have more water than flour. Doughs also tend to be simpler in terms of ingredients, often consisting of just flour, water, leavener, and salt. Many batters have several additional ingredients, including eggs, sugar, flavorings, and various sources of fat (butter or oil, milk, the egg yolks, etc.). Bread doughs, meanwhile, are more often leavened with yeast, while batters tend to be leavened by gas-producing chemicals like sodium bicarbonate (baking soda).

Yet all of this is a generalization. There are doughs with eggs and fat (hello brioche!), and batters that are little more than flour and water. Similarly, there are doughs that are raised with baking soda (they don’t call it soda bread for nothing) and batters teeming with yeast.

To put it bluntly, there’s more complexity and nuance to these categories of food than I can account for here, and many recipes exist on a spectrum somewhere between the doughiest dough and the batteriest batter. So, in the interest of getting the basic points across, we’ll be looking at the most stereotypical versions of bread dough and cake batter.

The Beginning of Bubble Life

Close your eyes and picture this: You’re inside a mass of bread dough that has just had its ingredients of flour, water, yeast, and salt combined. Stretching off in all directions are chains of gluten proteins that seem to go on for miles, so long they fade into the murky distance. You can see that the gluten proteins are just starting to bond with each other to form a network that will be critical to all that happens next. They’re going to give this bread dough strength and elasticity—which will be essential for trapping the gas bubbles later on.

You can also see starch granules everywhere, suspended in the watery matrix of gluten proteins like boulders tangled in an underwater net. They will eventually swell with water and later, when heat is applied, they’ll gel and set, turning a soft dough into something much more solid.

You can also see yeast cells beginning to feed. They’re eating the starch granules, digesting the glucose inside to generate energy and producing alcohol and carbon dioxide (CO2) in the process. Despite imagining ourselves at such a tiny scale, the carbon dioxide is still much, much smaller, and therefore impossible to see. The CO2 molecules are diffusing across the yeast cell walls into the watery solution that surrounds them—not as bubbles of gas, but as molecules dissolved in the water. The yeast will continue to eat the glucose in the starch granules and produce more and more alcohol and CO2, but it will take a while; they work slowly and are just getting started. Good thing is, in a bread dough, time is on our side: The yeast have a massive supply of food and there’s a lot left for the baker to do before the dough is ready for the oven.

Speaking of the baker, they’re about to do something important: Knead the dough. If you get motion sick, you may not want to imagine you’re inside the dough at this point, but a lot happens here. First, the baker is mixing the ingredients more thoroughly, distributing the starch, proteins, salt, and yeast more evenly throughout the mass, which will ensure a more even crumb later. All that mixing is also working the gluten proteins round and round, helping them to bond to each other and building an even stronger network to trap air. But there’s a third thing that’s often overlooked in the explanation of why we knead dough: Air pockets and bubbles are being worked into it.

Doughs and batters (and the finished baked breads and cakes) are foams, just like in this fizzy drink.

Without mixing and kneading, it would take longer for a yeasted dough to aerate, and the size and distribution of the eventual air bubbles will be more uneven in both size and distribution (some breads are kneaded minimally precisely to encourage large, uneven bubbles). By working air into the dough mechanically, the baker gives a jump-start to the aeration process, offering sites for larger bubbles to form throughout the dough, while also evening out the bubbles in the crumb.

At the same time, the dissolved CO2 that’s being excreted by the yeast is diffusing through the water in the dough. Anywhere these dissolved CO2 molecules encounter an irregularity in the mass of dough—and there are irregularities everywhere, from the varied shapes of starch granules to impurities in the dough and bits of salt—they will gather and cluster to form the teensiest, tiniest bubbles. This is the same thing that happens in a glass of beer or soda, where microscopic irregularities on the surface of the glass provide nucleation sites, as they’re called, for bubbles to form, eventually break free, and float upwards.

The big thing to know here is that in a dough, there are two pathways for bubbles to form: Larger ones of atmospheric air (mostly nitrogen and oxygen) that are incorporated mechanically when the dough is mixed and kneaded, and miniscule ones of CO2 that are forming at nucleation sites throughout the dough. Additional dissolved CO2 will find its way as it travels through the watery phase of the dough to these bubbles, where it can then escape into them as a gas.

Let’s now move by power of imagination into a batter. Sploop. We’re now bobbing in a thick slurry that was stirred together just moments before. Here, you have a lot more water along with several other ingredients—dissolved sugar, eggs (including emulsifier-rich yolks), fats, flavorings (is this a chocolate cake? Let’s pretend it’s a chocolate cake—I can definitely see chocolate now!), and even more fats, sugar, and proteins from milk. Gluten proteins float through the swampy mix with us, but they seem to be struggling to form much of a network—the fats in the batter appear to be attracted to the gluten proteins, and they’re getting in the way of the kind of gluten-to-gluten bonding we saw in the dough.

In this swampy batter, we see no yeast. Instead, there’s a chemical fizzing away: sodium bicarbonate (baking soda), which has wasted no time reacting with acids in the batter. The byproduct, once again: CO2. The whole pace of activity is different here. Unlike the snail-like pace of the yeast in the dough we were just in, the baking soda in this batter is just going absolutely nuts. One thing is clear: batters like this one are developing on a much shorter timescale than doughs—there’s no time to wait for yeast to slowly build up a supply of CO2, it’s being created in much greater quantities by the baking soda as soon as the batter is mixed.

Swimming through this slightly viscous batter, we can see the lingering effects of the mixing that the baker did right before we dropped in: the mixture is homogenous, thanks to all that mixing, and little bubbles of atmospheric air are suspended in the floury soup. In this way, the batter is very much like a dough. But, unlike a dough, gluten didn’t really have much of a chance to form here—there’s no elastic network of wheat proteins to trap air nearly as effectively as in a dough.

From the beginning, these batter bubbles tend to be smaller than what we saw in the dough. That’s because batters are rich with emulsifiers from egg yolks and other ingredients that work as surfactants to help form a stable shell around the bubbles—the more emulsifiers there are, the smaller the bubbles can be. If our baker were to reduce the amount of emulsifiers in the batter, we’d see larger bubbles because there simply wouldn’t be enough surfactants available to cover the increased surface area of smaller bubbles.

Serious Eats / Amanda Suarez

Aside from these differences, the processes we’re seeing in a batter are largely similar to a dough: the dissolved CO2 created by the baking soda diffuses through the water phase of the batter, nucleating on physical imperfections to form the tiniest bubbles, while mechanically-incorporated air provides a bubble-boost to further aerate the batter.

With the bubbles formed, it’s off to the races. For bread, this will be a long-distance run. For the batter, it’s more like the 100-meter dash. But there’s no need for a winner here, we’ll get our delicious and airy baked goods eventually.

Let’s stay in the batter for a moment, because some interesting things are happening here in the short time we have before baking. As I described above, we’re floating in a more liquidy medium, rich with egg and wheat proteins, emulsifiers, starches, sugars, baking soda, flavorings, and, at this point, lots and lots of tiny bubbles.

Because of the relatively lower viscosity of the batter compared to the dough, the bubbles are moving around much more easily, and they’re moving up due to their buoyancy. At the surface, bubbles pop and release their gas into the air, like sulphur burbling up through a muddy geothermal spring (thankfully, minus the sulphur part). The batter is degassing much faster than the dough—it has no good way to truly trap the air bubbles the way a stretchy dough can. It can slow them down, but they’ll eventually find their way to the surface and out into the air. Hence why we need to bake the batter sooner rather than later.

* Okay, okay, that’s a cop-out. Want to know why smaller bubbles have higher pressure than larger ones? Mostly, the answer has to do with the surface tension of the bubble’s shell: Smaller bubbles have a more extreme curvature than larger ones, and more curvature puts the bubble under more pressure, similar to how a tiny balloon is so much harder to blow up than a large one.

All of this coalescing and ripening drives the bubble structure towards an equilibrium in bubble size. At the same time, there’s an upper limit on bubble size in a batter. The reasons are many. Part of it is just time—a batter, being a shorter-lived foam compared to a dough, has less time to amass larger bubbles. Part of it is buoyancy: As bubbles become larger, they float to the surface more quickly, exiting at the surface of the batter. Bigger bubbles go bye-bye more quickly.

But another big part of it is the nature of the surrounding batter slurry, and once again we get to a fundamental difference between doughs and batters here. In a dough, the air is trapped in a strong but elastic gluten network that can swell and swell as the bubbles collect more gas. In a batter, though, there’s no significant gluten network to trap the air. Instead, the bubbles are held stable by the emulsifiers in the wetter batter, and there’s a threshold at which a bubble in a batter just can’t get any larger or it’ll pop due to instability. Plompfffffffff-blub, I think, would be the appropriate sound to imagine here.

The dough, meanwhile, is growing much more slowly, the gluten network expanding like a bunch of rubber balloons to contain a greater quantity of air as the yeast produces more and more of it. While coalescing and Ostwald ripening can happen in a dough, it’s much less frequent due to the lack of mobility of the bubbles in a lower-hydration mass of dough; on top of that, the gluten network acts like barriers for bubble crowd-control, making it more difficult for those bubbles to interact freely. So much of bread-making at this point involves the baker, who can influence bubble size and distribution with a variety of techniques, from a very hands-off no-knead approach for bigger, more uneven bubbles to methods that involve active folding, punching down, slapping, and more, to divide bigger air bubbles into smaller ones while improving the evenness of their distribution.

Immortality (-ish)

It’s time to bake. Thankfully, one of the benefits of imagining we’re inside bread dough or cake batter is we can stay “inside” during baking without actually being roasted to death. Our batter has now been transferred to cake pans, our bread loaf is formed, fully proofed, and ready to go into the oven.

For cake batter, the oven temperature is generally a cooler 325°F or so. Bread goes into hotter ovens of at least 400°F, sometimes much hotter (think: Neapolitan pizza in an 800°F oven). Why the difference? With bread, we tend to want a dramatic and rapid oven spring, the dramatic increase in volume mostly caused by steam as the water in the bread vaporizes in the heat—once the exterior dehydrates enough to begin forming a crust, it won’t allow much further expansion. This is also why breads are often baked with steam or spritzed with water in the beginning stages, to stave off crust development and allow more oven spring.

Cakes, on the other hand, do not require as dramatic of a rise, nor do we want them to form tough crusts, hence the lower oven temperature. Plus, cakes, with their finer bubble size, tend to be more dense than breads, so it takes heat longer to penetrate to the center; if the oven were too hot, the cake would harden on the exterior and still be raw in the middle. More moderate heat helps the cake cook through without over-baking on the outside.

Here, once again, we need to stop and appreciate one of the most important transformations that happens in the whole life story of the bubbles in these baked goods. Up until this point, the bubbles in both cases were forming what is called a closed foam, meaning each pocket of air is discrete and cut off from the rest. Think of the unbaked bread or cake like a huge house with tons of rooms (the bubbles) that each have an explosive device in them. Before baking, all the rooms have all their doors closed. If we were to light a fire in one room, it would eventually cause the explosive device to combust, blowing the door right off its hinges and opening the room up to the next. The heat would then rush into the next room, build, and blow the next device, and on and on until almost no rooms have doors anymore.

The same thing happens in a mass of batter or dough. As heat enters, starting from the outside and working its way to the center, water begins to vaporize and form steam, expanding a whopping 2000 times in volume compared to its liquid state. The bubbles expand, and then they burst into their neighbors’ spaces, in a chain reaction of ruptures and explosions that drive heat much more rapidly towards the center, speeding up cooking, and turning the baked goods into open foams.

Which is to say, by the time they’re baked, breads and cakes are no longer filled with thousands or millions of little bubbles, but rather one huge bubble that snakes and weaves its way through the crumb.

Up until baking, the bubbles in our batter and our dough had acted as a kind of internal support structure—in a sense, the bubbles were a solid framework holding up the liquid substance filled with starches and proteins. But as the bread and cakes cook, the starches gel and, in the case of egg-enriched batters, the egg proteins denature, firming up the crumb and setting the baked goods in their final solid form.

Once they’re cooled, as the accumulated gas and steam that provided so much expansion just minutes before drift off into the atmosphere, the loaves and cakes will not collapse. The bubbles that formed them have been immortalized in a final casting. Well, as final as any cake or bread will ever be, anyway, because I’m hungry. Can I interest you in a slice?


  • Harold McGee, On Food and Cooking (Scribner, 2004)
  • F. Ronald Young, Fizzics: The Science of Bubbles, Droplets, and Foams (The Johns Hopkins University Press, 2011)
  • Sidney Perkowitz, Universal Foam: Exploring the Science of Nature’s Most Mysterious Substance (Anchor Books, 2000)

I would be lying to you if I said I was a scientist. I’d also be lying to you if I said I wasn’t absolutely fascinated with it. That said, I have spent plenty of time researching chemical and physical changes and can confidently state that baking a cake is a chemical change.

Hey, there! My name is Michelle and I am a home baker that’s been mixing, whirring, and creating for the past ten years. During my time baking, I have learned that baking really is a science. I wanted to learn about the scientific aspect, which led me to this post.

If you have ever wanted to learn about whether baking a cake was a chemical or physical change, you’ve stumbled across the right post. Below, you will find plenty of information about how and why baking a cake is a chemical change – not a physical one.

  • Is Baking a Cake a Chemical or Physical Change?
  • FAQs
  • Final Words

When you bake a cake, you’re doing more than just crafting something delectable – you are also doing science. (Maybe this is a great way to teach some science to your kiddos out there?)

More specifically, you are creating a chemical change. That’s because baking a cake creates a chemical change, NOT a physical change. Why? Because a chemical change occurs when molecules (those found in cake ingredients) of more than one substance are combined, rearranged, and formed into a new substance entirely.

There are a few key indicators that prove a chemical change has occurred:

  • Change in the smell – Your baked cake smells much different than the batter you started with
  • It gives off or takes in heat – Your cake is baked in the oven, creating an endothermic reaction which means it takes in heat. (The other option is exothermic which gives off heat – both involved in chemical changes)
  • Gases being released – When your cake is baking, gases must release in order to create a lightweight, airy, and fluffy cake.
  • Can’t go back to original form – Once your cake has been baked, it cannot be returned to its original form (separate flour, eggs, sugar, etc.)
  • Transformation – The biggest indicator of a chemical change is transformation. Clearly, your cake transforms from a thick batter to a light and fluffy cake after being baked, thus proving a chemical change has taken place

Why Is Baking a Cake Not a Physical Change?

To understand why baking a cake is not considered a physical change, it’s important to understand what a physical change is. A physical change occurs when something the way it looks is altered, but the composition remains the same.

Think of a physical change such as tearing paper. The paper has changed, but the molecules of the paper remain the same. It is also able to be put back together, although it may be challenging. But being able to return to the original form is a key indicator of a physical change.

Looking to find out more about chemical changes and physical changes? Here is a great education website that goes into great detail about both.

It’s pretty exciting to learn that you’re essentially doing a science experiment every time you engage in baking a cake. If you’re still curious about this query, then check out these frequently asked questions below.

What are the chemical changes in a cake?

Cakes undergo several chemical changes while mixing and baking, from the gluten formation to the browning and binding. One of the most interesting chemical changes is baking soda reacting with acids to create carbon dioxide, which is necessary for your cake to rise.

Is baking muffins a physical change or a chemical change?

Since muffins are made in a similar manner to cakes, it’s clear that muffin-making causes a chemical change rather than a physical change. Remember, muffins are transformed from batter and it is an irreversible process, making it a chemical change.

Baking bread is also a chemical change. It starts with the batter being made, then allows the dough to rise. From there, the bread is baked in an oven and transformed from a dough to a loaf of bread that can’t be reversed.

Final Words

When it comes to baking a cake, you’re doing more than making a treat for your friends and family members. You’re creating a science experiment that results in a chemical change. That’s because cakes transform and are irreversible once baked, indicating a chemical change.

I have been a lover of sweets since day one. This led me on a self-taught baking journey starting at the age of 13. It’s been over 10 years since the start of my baking adventures, and I’ve learned a lot along the way. Now, people rave about my delectable treats, whether it’s a chocolate cake or a strawberry crepe.

Bread making can be as simple as just mixing some ingredients, waiting and baking, to a complex multi-step process. Depending on what style of bread you’re after, you might choose for one over the other.

Basic steps for making bread

  • Step 0: The Ingredients
  • Step 1: Pre-fermenting
  • Step 2: Mixing & kneading doughKneading by hand vs mixerTips for mixing & kneading
  • Kneading by hand vs mixer
  • Tips for mixing & kneading
  • Step 3: First proof / Bulk fermentation
  • Step 4: Shaping
  • Step 6: Final proof
  • Step 7: Scoring
  • Step 8: BakingOven spring, yeast’s last growth spurtA crust forms and browns
  • Oven spring, yeast’s last growth spurt
  • A crust forms and browns
  • Step 9: Cooling & Eating
  • Step 10: Practise & improve

The Ingredients

Before you start actually making bread, you need to choose the ingredients you’ll be working with. These ingredients will impact your process, but also the final texture, flavor, and appearance of your bread. You can make a bread with as little as two ingredients, but most use at least four: flour, water, yeast and salt. A bread made with these ingredients is often referred to as a lean bread. For a little more complexity and a new range of textures and flavors, you can create an enriched bread by adding fat, eggs, milk and sugar. Once you’ve chosen your ingredients, it’s time to get to work.


This first step is optional. A pre-ferment is a mixture of part of the flour, water, and yeast from the bread that is left to rest and ferment before incorporating it into the rest of the dough. A sourdough starter (or levains), sponge and poolish are all examples of a pre-ferment. Pre-fermenting part of the ingredients has a few advantages:

  • Flavor formation: if yeast is given time to ferment, it develops a lot of flavors, resulting in a more well-rounded loaf of bread
  • Hydration of the flour: this is especially helpful if making a bread with a lot of whole wheat flour. Whole wheat flour contains the bran of a wheat kernel. This takes longer to hydrate and absorb moisture than the rest of the flour. By pre-fermenting, it now has time to do so.
  • Flexibility in time: most pre-ferments don’t require very precise timing. An hour more or less often doesn’t do much harm. As such, you can get this going in advance, without necessarily impacting the rest of your process and timing.

A pre-ferment made of 750g whole wheat flour, 750g water and 1/8 tsp instant yeast. It’s been left to rest for approx. 18 hours before using it in bread.

Mixing & kneading dough

Next it’s time to mix the ingredients to actually start forming a bread. It is generally easiest to mix the dry ingredients first. This ensures minor ingredients such as salt and yeast are mixed in homogeneously. Next, it’s time to add the wet ingredients. Once moisture has been added, the actual bread-making starts. A dough starts to form, yeast is activated and ingredients start to interact.

Once the main ingredients are in, it is time to start kneading. Kneading is nothing more than continued intensive mixing. During kneading the ingredients are mixed, but, more importantly, the proteins are activated and will start forming a gluten network. By the end of the kneading process you should be able to take a piece of dough, gently pull on the sides and form a very thin, stretchy piece of dough. This indicates that a good gluten network has been formed. It is appropriately called the window-pane test, since you should be able to look through that thin piece of dough.

Kneading also introduces air into the dough which helps create a light and airy bread. Even though yeast will produce gas bubbles during proofing, generally speaking, most air bubbles are formed during kneading and they merely expand later in the process.

Kneading by hand vs mixer

Kneading by hand requires practice and patience. But once you have both, there are countless ways to properly knead a dough by hand. There are several techniques for doing so: repeatedly smashing the dough on the counter, pulling it apart and folding it over, continuously folding the dough over and over, etc. It requires skill to develop the gluten sufficiently and ensure enough air bubbles have been trapped within.

For the less experienced kneader, or if you need to knead a lot of dough, an electric mixer is a great solution. A small or large mixer with dough hook will do the job for you. The dough hook helps pull the dough along, folding and unfolding it upon itself, stretching the dough as it goes to make a smooth consistent dough.

Is kneading necessary?

Yes, and no. It depends. Kneading and time go hand in hand. During kneading you’re forming gluten networks. Given enough time and water, these gluten networks can also be formed without extensive kneading. However, in that case you need to give the dough time, often at least 24 hours for the structures to form. It’s a method we used when making bread in a LoafNest.

Tips for mixing & kneading

During this step there are a few key considerations to keep in mind:

  • Yeast is very temperature sensitive. It can get killed if you add very hot ingredients – don’t let the yeast get above 40°C (104°F). But it can also slow down considerably when adding (very) cold ingredients.
  • Fats interfere with the formation of a gluten network. This gluten network is crucial for many breads t to be able to expand and rise well. As such, it is often best to add the fat after the other ingredients have been mixed together into a dough.
  • Inclusions: if you’re planning on adding pieces of other ingredients such as nuts, cheese, meat, or dried fruits you can do so at the end of the kneading phase. Don’t do it any sooner or you’ll interfere too much with the gluten formation and you’ll run the risk of breaking up your inclusions! Some bread styles will only add the inclusions after the first proof which is also possible.
  • Over kneading: it is quite easy to see when a dough has not yet been kneaded enough. It might not yet be smooth and not pass the ‘window-pane’ tets yet. However, keep in mind that you can also over-knead a dough. Longer isn’t always better, when it’s done, it’s done.
  • Take some extra time: some recipes may call for quickly mixing the main ingredients (flour, water, yeast) and then resting it for 15-30 minutes before properly kneading it. During this resting time, flour gets a chance to hydrate. After this resting period the dough will be more flexible, making it easier to knead into a good dough.

Brioche dough, freshly kneaded and ready for its first bulk fermentation.

First proof / Bulk fermentation

Once a dough has been made it needs to rest. Doughs without yeast just need some time to relax the gluten network before they’re processed further. However, yeasted breads need more time because the yeast needs to get to work!

Yeast ferments sugars, either from the flour or from sugars that have been added directly. During fermentation, yeast converts these sugars into carbon dioxide 2, a gas. This gas is responsible for the increase in volume of dough during this phase. The extra gas pushes the dough up, supported by the gluten network that was developed during kneading. But that’s not all. During fermentation, a wide range of flavor molecules can be formed, if the yeast is given enough time. This can add an extra layer of depth to the flavor profile of your bread.

Keeping yeast happy by controlling temperature

Yeast are living organisms. As such, just like humans, they thrive under certain conditions and are less happy under others. For one, yeast have an optimal growth temperature. That is the temperature they grow and ferment fastest. They don’t grow (or very slowly) at temperatures (well) below or above this ideal temperature. If the temperature is too high they may even be killed.

Varying temperatures in your kitchen of bakery can drastically affect proofing times. For optimal control, you can use a proofing cupboard/drawer during proofing which is what professional bakeries will do. It makes the process more predictable, but it is not a requirement.

Some recipes will tell you to store the dough in the fridge for a long proofing time. In the fridge yeast will still be active, but way more slowly than at room temperature. As a result, it takes a lot longer for the dough to proof. But, this gives the dough time to properly hydrate, and it gives yeast and other microorganisms the chance to form a wide range of flavor molecules!

Controlling humidity to prevent dry dough

Proofing can take a while and you do not want the dough to dry out. You can prevent this by properly covering the bowl in which the dough is rising, without the dough touching that cover. At home, a great way to cover your bowl is by using a shower cap, it’s waterproof and reusable many times!

A shower cap gives the dough plenty space to rise. If you use transparent ones you can even see what’s going on in there :-).

Tips for proofing

  • Re-use a bowl: you can proof the dough in the same bowl that you kneaded it in. There is no need to transfer it to a different container!
  • Oil the dough: to make it easier to take the dough out of the bowl after proofing, you can coat the dough with a thin layer of oil, this prevents sticking to the sides.


Depending on the bread you’re making you may use the whole piece of dough for one loaf of bread, or you may need to portion it into several smaller pieces. If doing the later, cut it in such a way that the dough already resembles the final shape where posisble. So cut squares for a round douh and rectangles for an elongated long dough. Use a dough scraper to remove and cut the dough, or wet/oil your hands to help ensure the dough doesn’t stick to everything.

Punch it down

Next, you’ll generally want to punch down the dough lightly. That is, you push out some of the air again. The reason for doing so is that you’re giving the yeast extra food to go at it another round. It also prevents some very large bubbles from forming. But, be gentle here, you don’t want to push out all the air or your bread won’t be as light as you’d be hoping for.

Add tension

It is now time to shape the bread. Shaping adds to the visual appeal of a bread, making a baguette a baguette and a braided challah in to a braid. But is also has a more technical function. During shaping you’re adding tension to the dough by folding or tucking it into oneself. This tension helps create a better loaf. The gluten strands tighten up which helps the whole piece of dough to rise evenly. Unshaped, some parts might puff up more than others, resulting in uneven loads.

There are countless ways to do it (here are 10 ways to do so for plain breads, and here are more ways to do so for bread with a filling). Shaping is a skill that takes time to fully master. It may seem less important than some others, but once you get the hang of it, you’ll see the quality of the bread improve.

Final proof

Before the bread can be baked, it needs to rest and proof again. The yeast sets to work to re-expand the gas bubbles that were partially pushed down during shaping.

Since you’ve shaped the bread already, it’s important not to break up the shape again during this final proof. A lot of special tools exist, especially for special breads, but you can proof most breads with simple tools. There are a few options to do so.

Proofing in pan

Proofing on tray

  • Proof on baking sheet: if the bread will hold its own shape, proof it on a baking sheet, can be the one you’ll be using to bake it on. Do cover the tray + bread to prevent it from drying out, either with a towel or a large (garbage) bag.
  • Baskets, or bannetons: these baskets will help a dough keep its shape during proofing. An added benefit is that they let the outside of the dough dry out ever so slightly. This makes it easier to score the bread later on.
  • In the pan: for breads baked in a pan, proofing can be down within that pan. It helps the dough keep its shape.
  • A couche: some breads, such as a baguette might need something more custom. These are often proven on towels/linen folded in such a way that they support each other, without the dough of two separate baguettes touching.


Just like shaping, this step is easily overlooked. And, just like shaping, scoring can both make a loaf look better, and improve its overall structure. During scoring you make slight cuts on the top of the dough, just before baking. You’re essentially cutting through the gluten strands. This makes it easier for the dough to continue expanding and opening up in the oven. If you don’t score these breads, they might ‘explode’ at their weakest spots, which simply doesn’t look as nice as a scored expansion. But you can also use it merely to add a pattern on top. Again, practice makes perfect here.

Not every bread needs scoring to expand properly. Doughs with a lot of fat, or very wet doughs, may not need it.

The pattern on top was achieved thanks to scoring the dough before baking,

Last, but not least, it’s time to bake that bread. This is where that soft, flexible dough transform in a firm set loaf of bread. Bread is baked by placing it in a hot oven. The heat cooks the starches and proteins, and sets the bread. There are a lot of different types of ovens that each work slightly differently both a lot can be used to make perfectly fine bread.

Oven spring, yeast’s last growth spurt

During baking a lot of things happen. First of all, the yeast gets one last growth spike. Just before it dies because of heat it will do one last burst of gas production thanks to the nice warm temperature. This causes the loaf to expand. The loaf also expands because existing gas bubbles within the dough start to expand. Hot gas takes up more volume than cold gas, as explained by the ideal gas law. Additionally, even more gas is formed because water starts to evaporate, again pushing the loaf up.


Many professional ovens inject steam during the beginning of the baking process. This helps create a nice crust and seems to help with the oven spring. At home, you can simulate this effect by adding a pan with hot boiling water in the oven for the first several minutes. Alternatively, you can bake bread in a pan with a lid. The pan serves as a tiny oven and traps the moisture that evaporates, creating a nice and moist environment for the bread. It’s a greaet way to replicate steam ovens and helps incresae that oven spring further. After the first 10-20 minutes simply lift off the lid to let he steam escape and let the bread turn brown anddry.

Removing a pan with hot water from the oven after the first 15 minutes of baking.

A crust forms and browns

The bread can only expand as long as the outside is still flexible. But, once in the oven, the outside will start to dry out, moisture evaporates. Combined with the cooking of the starches and proteins, the outside of the bread becomes firmer and a crust starts to form. Just how much of a crust is formed depends on the type of bread and the oven conditions. Higher heats give thinner and softer crusts whereas lower heats give thicker crusts since moisture has more time to evaporate.

Once the crust is dry and hot enough, it will also start to turn brown due to the Maillard reaction. It is important to set the oven temperautre such that the outside doesn’t turn too brown, or even black, before the inside has had a chance to cook. Breads with a high sugar content are especially prone to burning and turn often bakeed at a lower temperature.

Cooling & Eating

Once your bread leaves the oven, there’s just one step left before you get to eat it: cooling down. During cooling bread still loses a lot of moisture. It is important that this moisture can dissipate and isn’t trapped somewhere along the bread’s crust or it woul become soggy. So take breads out of the pan (unless you want a soft bread) and cool them on a rack for best result.

A cooled down bread starts to turn old almost immediately, so most, but not all, breads are best eaten fresh. Want to store your bread for some time? In almost all cases doing so in the freezer is the best choice.

Ready to be devoured, a pan baked garlic cheese bread.

Practise & improve

You won’t learn how to bake bread by just reading books. The best way is to just get started and start making some. Start simple and make things more complex as you go. Once you’re ready to dig in more, and when you’re looking for an in-depth discussion of all the steps that (can) go into making bread, you might want to read Modernist Bread, Volume 3: Techniques and Equipment. It’s an expensive series, so check it out at your local library first. It does contain a lot of information and especially a lot of beautiful visuals to explain what’s going on.

Various intriguing applications and industries use carbon dioxide, yet one that may often be overlooked is CO2’s influence in baking.

Is CO2 Important in Baking?

Non-bakers may not realize that besides ingredients like flour, sugar and eggs another common ingredient is baking soda, baking powder, or in the case of bread, yeast. These “magic ingredients” work with the other ingredients to release carbon dioxide (CO2).

For example, when leavening agents such as baker’s yeast or baking soda are added to bread dough, they release CO2 which forms bubbles to give the dough the perfect consistency and structure for it to rise. CO2 creates the light and fluffy texture in baked goods by filling the batter with pockets of gas as it bakes.

Carbon dioxide also happens to be one of the major gases responsible for leavening in baking. In cakes, it comes from the reaction of sodium bicarbonate under acidic conditions. That’s why for thousands of years bread has been made with only flour, yeast and water (skip the yeast and you have unleavened bread).

What’s more is that the added CO2 further results in the scrumptious bakery breads we gather today such as rye, brioche, sourdough and even that delicious holiday cornbread.

Bakeries use carbon dioxide all the time, especially in the final proofing stage before baking (resting to increase the volume of the bread). In a closed area with hundreds of loaves of bread, this can cause the CO2 levels to rise to potentially dangerous levels. This is why a large, artisan bread company in Minneapolis recently began using our CO2 Storage Safety Alarm to protect their employees from high levels of CO2 in enclosed bread rising rooms.

Fun Fact: One of a baker’s goals is to increase the volume of the bread to make it more “airy” and tasty. A loaf of bread will nearly double in volume, which you can see by looking at the holes in bread caused by CO2 bubbles.

During the proofing process, when CO2 is produced it begins to apply pressure which makes the dough rise. If the bread is not allowed to expand enough it may rise in the oven. If it is allowed to expand for too long, it may be “over-proofed” and deflate the dough.

Alcohol Also Helps Bread Rise

In addition to carbon dioxide, alcohol can play a significant role in making some breads rise. While most people think that carbon dioxide makes bread rise and alcohol changes the flavor, this is not entirely true.

When yeast breaks down glucose it transforms it into carbon dioxide and ethanol. Both byproducts are formed in equal parts. So for every glucose molecule, two molecules of carbon dioxide and two molecules of ethanol are formed. While at room temperature, the alcohol is liquid. When the bread hits the oven, the alcohol begins to evaporate, transforming into gas bubbles that contribute to the rise of the bread.

What Foods Use Carbon Dioxide?

While carbon dioxide serves incredibly useful in baking, it is used across the entire food industry.

  • CO2 gives your favorite soda and beer the sensational fizz of carbonation.
  • CO2 is used in drying to extend fruit and vegetables’ shelf-life
  • CO2 as dry ice is used for goods refrigeration in transit
  • CO2 is even used to euthanize animals before slaughter

CO2 gas is obtained from a wide range of sources, but it is generally recovered from industrial off-gases with varying degrees of purity. Much of it is produced in synthesis gas plants such as ammonia or hydrogen production, in breweries through the fermentation process, or, to a lesser level, combustion of fossil fuels such as natural gas.

Overall, many of the main foods you come in contact with have already been introduced to CO2 such as:

  • Livestock (Pigs, Chickens, Turkeys, Cows)
  • Dairy (Ice Cream, Milk, Eggs, Cheese)
  • Carbonated Drinks (Soda, Juices, Ciders, Lagers)
  • Packaged Foods (Meats, Cheeses, Fruits, Vegetables)

Is Carbon Dioxide Safe in Food?

As we have learned, many of our most common food and beverages use carbon dioxide, but does this come with any risks?

Carbon dioxide might seem harmless at first glance. After all, we exhale it with every breath, and plants need it for survival. Yet, the presence of carbon dioxide itself is not necessarily a problem, but it is the volume in any given environment that can rise to dangerous levels.

The fact that carbon dioxide is colorless and odorless makes it dangerous at high levels.

Since carbon dioxide is heavier than air, it also displaces oxygen. At high concentrations this will cause asphyxiation. In the event of a release, it’s easy to succumb to exposure, especially in a confined space like a tank or a cellar.

Early symptoms of being exposed to high levels of carbon dioxide include dizziness, headaches, confusion, and loss of consciousness.

Because of these severe negative health effects, many accidents and fatalities do occur in the food and beverage industry from carbon dioxide releases.

Without proper detection methods in place, everyone at a facility could be at risk. This is fairly common when one person shows symptoms of high carbon dioxide exposure and nearby workers attempt to help, only to become victims as well.

Many bakeries, restaurants, and beverage industries working around CO2 use the Remote CO2 Storage Safety 3 Alarm to provide employees with the ability to visibly measure the CO2 levels and trigger an exhaust fan should CO2 levels increase to a harmful level.

A Bloomberg study stated, “The equivalent of half a kilogram of carbon dioxide goes into the atmosphere for every loaf of bread produced in the UK”.

This is just one safety example of CO2 in regards to the baking industry and why use of a  CO2 safety monitor to can provide safety solutions to those in and around this invisible, deadly gas.

Aside from just implementation of CO2 in bread baking, another application which involves CO2 in bakeries is the cryogenic freezing of baked goods. In order to freeze a product for preservation, many industries in the baking fields use liquid nitrogen or CO2 as a freezing agent.

According to Baking Business, “Bakeries freeze raw, par-baked and fully-baked foods to extend shelf life, retain moisture and flavor, and increase distribution capabilities.”

Whether you are preserving baked goods with nitrogen or looking to gain the perfect appearance and volume in bread making with CO2 – the gases are all commonly used and safety solutions are available.

The team at CO2Meter is proud to have the opportunity to provide technologies and protect customers and workers near stored inert gases such as carbon dioxide, or even nitrogen in cryogenic applications.

Overall, be mindful this holiday when you are baking and having loved ones over to celebrate.  Even though you may not see, smell, or taste the inert gases – they are there.

Most bread recipes give you a time range for rising, but because kitchen conditions can vary, time isn’t always the best way to measure your dough’s readiness. For instance, if you’re given a rise time of 60 to 90 minutes, should you pull your dough at the front end of that range or later?

Hotline member Maggie is here with all the cues to look for so your next loaf comes out perfectly. Here are her recommendations for nailing your proof:

But first, why it’s important to hit that proofing sweet spot

Bread recipes typically call for two rises: The first is the “bulk” rise when the dough rises in the bowl, while the second rise comes after the dough has been shaped, like when a sandwich dough proofs directly in the loaf pan. “While you have some wiggle room with the first rise, the second rise needs to be more accurate to get a nice full loaf,” Maggie explains. If baked too soon or too late, loaves can collapse and have a dense, gummy center.

“There are so many factors that affect rise time, so exact time will vary for every baker. Things like the water and air temperature, humidity, how large the pieces of dough are, the vessel the dough is in, and how it was shaped will all change the way and the speed that dough rises,” says Maggie. With so many variables in play, think of the times provided in a recipe as a guideline rather than a hard and fast rule. Getting to know the look and feel of proofed dough will be your key to successfully nailing both rises.

Because of its straight sides, a Dough-Rising Bucket allows you to easily measure if bread dough has doubled in volume.

Visually assess your dough

For the first rise of the recipe, use a Dough-Rising Bucket with measurements up the side to easily know when your dough has doubled. If you have another straight-sided vessel without measurements up the side, you can use a piece of masking tape to mark the dough’s height when you set it to rest. You’ll be able to clearly see when it has doubled.

For the second rise, many recipes baked in loaf pans will recommend baking once the dough has reached 1” over the lip of the pan. Grab your ruler and check your dough periodically to ensure your dough isn’t under or overproofed. (For accurate results, be sure to use the size of loaf pan listed in your recipe.)

A good rule of thumb: Once your dough has reached 1” over the edge of a loaf pan, it’s typically ready to bake.

With free-form breads like rolls, pizza crust, or boules, it can be trickier to tell by visuals alone. You can’t gauge rise using the dough’s height over the loaf pan, and if you aren’t a frequent bread baker, it can be tricky to tell if the dough has doubled in volume. While you could measure your shaped dough’s height with a ruler, the dough will be rising outward as well as up, so this is where the poke test can be a better way to gauge readiness.

Physically test your dough with the poke test

“Don’t be afraid to touch your dough!” Maggie advises. “When ready, it should feel a bit elastic and have some bounce to it, but it shouldn’t feel dense or stiff in any way.”

What bakers call the “poke test” is the best way to tell if dough is ready to bake after its second rise. Lightly flour your finger and poke the dough down about 1″. If the indent stays, it’s ready to bake. If it pops back out, give it a bit more time.

The poke test is especially helpful for free-form breads like cinnamon rolls.

This method works with dough in many forms: pan loaves, free-form loaves, rolls, pizza, and more. Start poke-testing your dough toward the beginning of the rise-time window specified in the recipe. If the temperature and humidity in your kitchen are high, it’s likely your dough will rise faster than you expect. On the flip side, expect longer rise times when the air is cold and dry. Either way, testing early is better than missing your ideal window.

Practice makes perfect

With more experience, you’ll become better at identifying the sweet spot when your dough is proofed. To really nail things down, take notes on the timing and conditions of your dough that you can refer to next time. Soon you can use these learnings when baking other bread recipes as well.

For a more hands-off approach to mastering the perfect proof, a Folding Bread Proofer creates the ideal environment for your dough to thrive.

Science is all around us.

Oftentimes, we apply the principles of physics, chemistry or biology without even knowing.

We can all be scientists and we are by observing and studying carefully what happens around us.

Baking is a good example.

Kids love baking and playing with the dough.

Making bread with kids is full of teaching moments.

Try this science of break making experiment.


  • 1/3 package active dry yeast
  • 3/4 cup warm water
  • 1 tablespoon sugar
  • 2 1/4 cup all purpose flour
  • 1/3 tablespoon salt
  • 2/3 tablespoon cooking oil (e.g. canola oil) or butter


the space created by the air pockets’ expansion gives the bread a soft texture.

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