Learn the basics of how to bake with yeast in my baking science series! In baking with yeast 101 you will learn the basics of what makes yeast grow, what puts it to sleep, and how to avoid killing your yeast!
When I first started baking I would not even consider making a recipe that called for yeast. For some reason, baking with yeast seemed like an overly complicated task that only the most skilled of bakers could do properly. And while the statement that baking with yeast can be very complicated and intricate is true, in many situations this just isn’t the case. Making many yeast breads is actually incredibly simple and with a little knowledge of how yeast works anyone can do so confidently.
Let’s start first with the simple definition of what yeast is. Yeast is a fungus. Yep, you heard me correctly. Yeast is alive, it is a fungus, and it happens to be everywhere. Yeast is floating through the air, living in our bodies, on our skin, in the dirt, and is naturally occurring in many foods that we eat. But the yeast that we are talking about here is the commercially produced yeast for the purposes of baking. The yeast home bakers use to produce the most delicious breads and pastries.
Forms of Commercial Baking Yeast
Many bakers make breads from their own yeast starter which consists of natural yeasts that have been collected from the air. This is a big topic and one for another day. I recommend starting with commercially produced dry yeast when you are first learning about baking with yeast. Commercially produced yeast for baking is sold in 3 main forms: Cake yeast, active dry yeast, and instant yeast.
- Cake yeast, also known as compressed yeast or fresh yeast, is sold in compressed cakes. It is a highly perishable product that must be kept in an airtight package in the refrigerator and even then it spoils very quickly. This type of yeast, unlike the other two kinds we will discuss, is very moist and therefore in an awake state. Fresh yeast has become increasingly difficult to find in grocery stores, at least in the states, due to its very brief shelf life. For this reason, we will not be focusing on fresh yeast in this post.
- Active dry yeast is a dormant form of yeast cells that have been dried. Because active dry yeast is dormant, an unopened package can be kept at room temperature for two years (source). This yeast needs to be proofed (woken up) in warm liquid before used in a recipe. The ideal temperature for proofing active dry yeast is 105-110F.
- Instant yeast or rapid rise yeast is also a dormant form of dried yeast cells, however these yeast cells are much smaller (source) and therefore absorb liquid more quickly than active dry yeast. This yeast is most commonly used with bread makers, though it can also be used in traditional bread making. This yeast should be added in the with dry ingredients and does not need to be proofed in liquid. The warm liquid is then added into all of the dry ingredients. It works best at slightly warmer temperatures than active dry yeast, at about 120F. Because this yeast is highly active when it first wakes up, it does slow down as time goes on. Rapid rise yeast or instant yeast is not recommended for recipes where the dough will be refrigerated for a period of time before baking.
What puts yeast to sleep?
- Lack of moisture: Yeast needs moisture to remain in its active feeding state. The removal of all moisture in the process of making dry yeast does not kill the live cells, it simply puts the yeast in a dormant state, or puts the yeast to sleep so to speak.
- Cold temperatures: Cold temperatures are to yeast like a soft lullaby is to a snuggly baby. Yeast that is already hydrated and active in a dough will slow down if put in the refrigerator. The yeast will not go completely dormant if it is hydrated, but the fermentation process will slow down significantly. Sometimes yeast doughs are refrigerated in order to retard the rise of the dough so that it can be baked at a later time, while other times doughs are refrigerated to create a longer fermentation process which will develop more flavor in the final product.
What wakes yeast up?
- Moisture: Dry yeast needs some type of moisture to pull it out of its dormant state. Most bread recipes use either water or milk for the liquid component.
- Warm temperatures: Yeast loves warm temperatures. The liquid used in a yeast bread recipe should typically be around 105-110 degrees F (source) for active dry yeast and about 120-130 for instant or rapid rise yeast. Now I know you are thinking that this means you need to get out your thermometer and therefore you are already checked out. But honestly, for basic breads this really does not need to be super precise. Very serious bread makers will likely argue this point, but for the purposes of a home cook making simple breads you really don’t need to. You want water that is warm, but not hot. Consider that your body temperature is 98.6 F, so therefore you want wanter that is slightly warmer than body temperature. I usually put my finger under the running faucet until it feels warm and then measure out my water. It hasn’t failed me yet. BUT, if you are nervous about it, then by all means use a thermometer. If the water is too hot to touch, then it is too hot for the yeast!
What makes yeast grow?
- Sugar: When yeast is alive it feeds on sugar and produces carbon dioxide. And when I say that yeast feeds on sugar, I do not just mean granulated sugar. Yeast will feed on the starches in flour as well as any other sources of glucose in the dough. The process of yeast metabolizing sugar and producing gas is called fermentation. Fermentation is what develops flavor in yeast breads as well as what makes the bread rise.
- Warm temperatures: Like I said before, yeast loves the warmth. Yeast grows the best around 79F (source). This does not mean that temperature that is slightly warmer or cooler will kill the yeast, it just means this is the ideal temperature. When letting a bread rise you want to try and find a warm spot for it to do so. I like to put my rising dough inside my oven that is off. It is typically slightly warmer than the rest of my kitchen.
What makes yeast die?
- High heat: One of the things I hear people say all the time is that they always kill the yeast in their bread. To be honest, it really isn’t that difficult to keep yeast alive. The biggest tip I have for you to make sure you do not kill your yeast is to keep it away from high heat until you are ready to go into the oven for baking. If the water is too hot when you re-hydrate the yeast then you could kill it. Error on the side of caution with the water temperature when you are first experimenting with baking with yeast. Yeast starts to die at 120 degrees F, and at 140 degrees F it will completely die.
- Salt (in high ratios): Salt is found in every yeast bread recipe I have ever read and that is because it does serve a purpose. Salt obviously serves to flavor yeast bread, but it also keeps the fermentation in check a bit and prevents breads from rising too quickly. However, in high ratios, salt can kill yeast and for this reason I always suggest adding in the salt after adding in the flour so that the ratio is diluted. You don’t want to add your salt right into a water/yeast mixture without the flour because you are risking killing the yeast.
The basic process of baking with dry yeast.
Keep in mind that this is the very simple standard procedure for bread making. Most bread recipes follow these steps in some form, but many may add in a few other steps along the way.
- Dry yeast is rehydrated in warm liquid
- Flour, salt and other ingredients are added to the liquid/yeast mixture. Usually these ingredients are kneaded together to develop the glutens, flavor, and color in the bread.
- The yeast feeds on the sugars in the flour and other ingredients and produces carbon dioxide which causes air bubbles and rise in the dough. This process is also called fermentation and creates flavor in the bread.
- The dough is shaped, usually allowed to rise again, and baked.
Troubleshooting: What can you do if your dough isn’t rising?
- Your yeast may be too old. Try again with a new package of yeast
- Your room may not be warm enough. Set the bowl next to a heating oven to provide some warmth.
- Your water may have been too hot and may have killed the yeast. Make sure the water is warm but not hot. You can use a thermometer to check for a temperature that is between 105F-110F.
Baking with yeast in its basic form is actually quite easy once you get in there and try it out. I encourage you to do so. I am going to give you a post tomorrow that is a very basic rustic yeast bread recipe and video tutorial for you to start with. This recipe is one of the easiest you can make with yeast and still tastes and looks incredibly impressive.
I have a few more posts lined up for this series that will address some questions I have received about baking with yeast. I would love to hear any other questions you may have about how to bake with yeast and I will definitely try to address them all!