Let's Talk about Yeast, My Favorite Microorganism

Oh yeast. One of my favorite things to exist in this universe. In college there was a joke that any baking students that loved bread classes were yeast sniffers. I wear that badge with honor not only for my love of yeast but any micro life. At the end of the day though, yeast is my #1. Although I love using wild yeasts in the form of sourdough, sometimes I need a quick rise in a dough to make something in a pinch or within a few hours. This is when dry yeasts come in handy and is always something I keep in the freezer to bake with. When you go to the store though, there are so many types. Active dry yeast, instant yeast, quick rise yeast, cake yeast in the refrigerated sections (sometimes). It’s hard to know what these all mean and do. So let’s talk a bit more about yeasts, the best uses for them, and which ones you really need to keep on hand.

Active Dry Yeast

First let’s talk about the yeast I see most often in recipes and out in the world, Active Dry Yeast or ADY. The process of cultivating and then drying this form of yeast is a bit rough on the yeast cells. It comes in a nice larger granular form but contains a high amount of dead yeast cells, about 25%! This increases the slack of dough and makes it more extensible. Damaged and dead yeast cells release a chemical called glutathione that weakens the gluten forming proteins. Cold water also allows more glutathione to leak from the damaged cells, so makes sure to always use warm water when activating this type of yeast! In many doughs this slack is not going to help, you want the loaves to hold their shape and not stretch too much. Although some doughs benefit from this. Pizza is stretch thin and wide, pita is thin and baked to have a pocket, most flat breads or any dough that is stretch out and thinner works really well with this type of yeast.

When using this active dry yeast, you do need to rehydrate it before adding into a recipe because of the larger granule size. Most recipes will say something about mixing some water and sugar with the yeast and letting it sit for 10-15 minutes. I find the 10-15 minutes isn’t necessary. Just enough to dissolve the yeast granules so that they are dispersed in the recipe. Dry active yeast also has a great shelf life which makes it great for home bakers that aren’t using yeast all the time. You can get it in jars or packets in the baking isle at room temp. They last awhile at room temp but can last even longer when refrigerated or frozen. Of course always test by dissolving some in water to make sure it’s active before using if it’s been awhile but it’ll last years in the freezer.

Instant Active Yeast

Instant Active Yeast is my favorite to use and the one use by many chefs. It is similar to active dry yeast but the process of producing and drying is a lot gentler to the yeast cells so there are less dead yeast cell that affect the gluten development in the dough. The granules are also finer and more porous so they can be thrown right into the recipe rather than take time to dissolve into water first. Saves time and is more efficient in the kitchen.

These yeasts also typically will have minerals or acids added to help with gluten development to produce really lovely doughs. I use a brand called SAF Yeast, it’s the most common I’ve seen by other chefs as well. SAF yeast specifically uses sorbitan monostearate that coats the yeast to help prevent oxidization and to better dissolve in water as well as ascorbic acid that helps with dough pH and gluten development. Each brand has their own additives, always check the labels to see what they use and adjust for recipes if necessary.

I personally love this type. The instant ability allows for quick mixing and inclusion into many doughs. Instant yeast is also very vigorous compared to other types of yeast. I can use less yeast by weight when using instant compared to active dry yeast to get similar results. This also means that I cannot exchange them one-for-one since instant will proof faster if added at the same weight as active dry. Instant yeast also is not the best for longer fermentation times, especially overnight proofing. Since it is so good at fermenting it’s great for one day doughs that you want to mix and proof within a few hours.

Quick-Rise Yeast

Quick-Rise Yeast is very similar to instant. It is milled into very small granules so that it can quickly dissolve straight into the dough rather than mixing with water to dissolve and proof before mixing. Quick-rise typically contains multiple additives like dough conditioners and enzymes to get a nice yeast activity in the dough, help with gluten formation, and allows the dough to be mixed and shaped immediately so that there is a single fermentation rather than two or more. This type of yeast should never be used in long fermented doughs and honestly is not common at all in the baking industry. This I mostly see in older recipes for home use where the home baker wants a quick dough that will mix, rise, and be ready to bake in an hour or so.

Fresh Yeast Cake/Compressed Yeast

Cake Yeast is a thick dough like substance

Fresh Yeast Cakes are literally living yeast organisms that are in a stiff dough like “cake” that you can dissolve in water and mix into the dough. I rarely see it in the store in the US but saw it a lot in stores when studying in Europe. Many high production bakers use this but it is starting to be phased out more and more as dry forms are more shelf stable and cheaper. Fresh yeast must be refrigerated and only has a shelf life of about 2 weeks. This means you must use it fast compared to dry yeasts that last months and even years in the freezer. Fresh yeast also needs to be dissolved in water before mixing similar to active dry. Again, this is why I love instant yeast. Quick and easy to throw into a dough without much wait time. There is a really cool experiment you can do with cake yeast though. If you get your hands on some, mix with a little salt in your hands and after a few moments it will quickly turn into a liquid as the salt takes the water from the yeast cells and creates a salt solution. The yeast dies in this experiment but a fun party trick to do with yeast lovers.

Osmotolerant Yeast

I have talked about Osmotolerant Yeast in other posts before. This is a specific type of yeast that has been bred to tolerate doughs that are high in sugar and fat. This type of yeast is great for doughs like brioche or sweet doughs. If you break down the word, it literally means to tolerate the process of osmosis. The transfer of water between ingredients in your dough and how that affect the living organism of yeast. You can still use other forms of yeast in high sugar doughs but you need more to balance the reduced activity of the yeast. Bakeries that make a lot of enriched doughs can save money by using this type of yeast since you can use smaller amounts with great results.

Substituting Yeasts

When it comes to recipes needing one yeast and you may have another there is some room to substitute the yeasts for each other. First off let’s talk about fresh yeast. Since it is living organisms and has a high amount of water you need more fresh yeast compared to dry yeasts. Many people go with the general rule of 50% dry yeast compared to fresh yeast. I have always gone off of the ratio of 40%. Let’s break this down. If you have a recipe that calls for 100g of fresh yeast you can times that by 0.4 to get the amount of dry yeast. So 100g fresh yeast is equal to 40g of dry yeast. Going the reverse way, you can divide the amount of dry yeast by 0.4 for the amount of fresh yeast. A recipe calls for 15g dry yeast, divide by 0.4 and you get 37.5g of fresh yeast.

When we get into substituting different forms of dry yeast that gets a bit tricky with comparing various brands and types of yeast. The general rule is that they can be substituted 1-for-1 by weight and only weight. Since instant is smaller granules than active dry, volume measurements will be different. A teaspoon of instant is going to have more yeast cells than a teaspoon of active dry. Instant yeast is also more active than active dry so it will ferment faster. Overall I try to work with a single type of yeast and stick with it. I make all of my non-sourdough recipes with instant yeast (SAF brand). If you change the brand or type make a small batch and see how it works. This is where you will need to have a better grasp of bread doughs and noticing when a dough has fully fermented by sight and feel.


Of course we need to discuss storage and the best way to keep your yeasts so that you can use them! It’s super important to store them properly, there’s nothing worse than waiting on a dough and not getting any rise or the results you want.

I mentioned above a bit about the storage of fresh yeast. It is the most sensitive to store since it’s fresh and living! It’s found in the refrigerated section of grocery stores. The colder temp keeps it in a hibernated state and not reproduce or ferment on its own. Once you bring it home you should still keep it in the fridge. It does not freeze as well as dry yeasts so don’t freeze it! This is one of the reasons you will see a lot more of the dry yeasts being used for how easy they are to store. The other main reason is the shelf life. Dry yeasts last a lot longer than fresh yeast. Fresh yeast only has a shelf life of about two weeks. Buy it only if you need it for a project you’re about to do, otherwise I just try to avoid it.

Dry yeasts on the other hand have an incredible shelf life. They are found in the baking isle at room temp so they can last quite a while at room temp. If you’re like me, you probably have heard the old school trick of refrigerating to make it last longer. I’m here to tell you to even go as far as freezing it to last even longer! I keep all my dry yeasts in airtight mason jars and in the freezer and they last a LONG time. I bake a lot so I do buy a pound at a time and go through that about every year or so, but if you get one of those small jars you can throw that right into the freezer and have yeast whenever you are ready! I’ve had students tell me their yeast lasted in the freezer over 3 years and still worked in the recipes I gave them.

The most important thing when storing yeast is to keep it dry. Yeast likes to be in warm moist environments. That’s when it multiplies and ferments the best. If we can go the opposite way and keep it cool and dry it can’t ferment. So keep the water away. Air tight containers as much as you can and you will have yeast for months to use and makes some incredible breads.

Geeze that was a lot of information but it is important information! Come back and review this page as you need to if you see or use a different yeast but again I want to emphasize, pick one brand and type of yeast and stick with it. Get used to it and how you can substitute it into recipes and you’ll get such great results in your home backing again and again. So join me as a proud yeast sniffer and let’s make some bread!

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