If 2020 taught me anything, it taught me to appreciate a good stockpile of yeast. I was already a seasoned bread baker before the shutdown and had a well-stocked pantry, but I hopped on the sourdough train because it feels like a good skill to have. Through that, I learned that I prefer to have yeast on-hand, and I started questioning how long it could be stored.
The time that commercial yeasts remain viable depends on how it is stored. Depending on humidity and other factors, if left open on a shelf, yeast will last less than a couple of months. Baker’s yeast stored in an airtight container in a cold freezer will keep yeast viable for years. Contrary to popular belief, yeast does not have a definitive expiry date.
While yeast absolutely will lose some of its potency over time, steps can be taken to slow down that process. I explain how you can keep dry yeast fresh farther on.
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How to Make Yeast Last Longer
According to the folks over at StillTasty, active dry yeast kept at temperatures below 0°F (-18°C) will keep indefinitely. I know from my own experiences that this is true. I found yeast that had to have been several years old that was still viable. There is a good chance that if it is stored in an airtight container forgotten in the back of your sub-zero freezer, it’ll be fine to use.
Note: If you store your yeast in the door of a freezer or if the freezer has an auto-defrost feature, your yeast may go stale sooner. Yeast doesn’t do well when forced to deal with regular temperature changes.
Vacuum sealing is my favorite way to store extend the life of yeast, especially if you’re buying big packages but only making bread once a week or less. You can vacuum seal much smaller amounts by sealing into a small bag. Put all of your homemade yeast packets in a Ziploc or appropriate container and throw it in your freezer. It’ll be good forever, assuming it was good going in.
This video explains how to create and seal small bags with a vacuum sealer.
How to Stockpile Yeast
The following rules are made with the assumption that you’re buying your active dry yeast in big packages. Buying in bulk is necessary when building a stockpile, though it may not make much sense for a small family or single person.
The First rule of storing active dry yeast: Keep it airtight.
When a new pack is opened, the contents should immediately be transferred to an airtight container fit for freezing. This can be a glass jar or a freezer-safe plastic container.
The Second Rule: Never store more than 4 months’ worth of yeast in a single open container.
When I open a 2lb brick of yeast, I don’t want to store all of that yeast in a single jar. Every time the jar is opened, the yeast is exposed to light, moisture, and heat, all of which will shorten its lifespan.
Instead, invest in some small jars or save any small yeast jars that you might already have on hand. Baby food jars would also work but are a little more fragile.
The Third Rule: Rotate your stock.
As I listed above, unopened bricks of active dry yeast can sit on a shelf for more than two years and still be considered fresh. By the time I open a brick, it’s usually two or three years old. I don’t want it to get any older than that, because I don’t want to be wasting freezer storage space.
Something I learned at my high-school fast-food job was to rotate your stock, and of course, it follows through to prepping. The older product is pushed to the front. The new product goes to the back. Always keep your stock organized so that you don’t waste time searching for which product is the oldest.
How Much Yeast to Stockpile
The first thing to remember that homemade bread is hardier and more filling than your average loaf of Wonder bread. If your family eats typical commercial white bread, count on using about half as many loaves, as homemade bread tends to be hardier.
To figure out how much yeast you would need for your stockpile, count on using roughly a tablespoon of yeast per loaf. Conveniently, there are about 52 tablespoons of yeast in a pound, so just multiply the number of loaves you think you would go through in a week by the number of years you want to stockpile.
Yeast Stockpile Formula
(Loaves of Bread Consumed per Week) x (Years to Stockpile) = lbs of Yeast to Stockpile
I’m going to use my storage and usage to give you an idea as to what you can expect.
As I said earlier, I make my own bread and have for years.
For prepping purposes, I keep about 3-4 years’ worth of yeast on hand. I’ve been rotating through this stockpile for over ten years. My yeast always fully activates even though it’s a few years old by the time I use it.
We go through about two loaves a week, which is roughly two pounds of yeast per year. This means I usually have two or three unopened 2lb pack of yeast in my stockpile and one open and in use. I keep so much on hand because, in an emergency situation, my family’s bread consumption would likely double as we lose access to more convenient foods. And I’d like to hold off turning the great sourdough experiment of 2020 into reality as long as possible.
It’s Okay to Use Expired Yeast
“But it has an expiration date printed right on it,” you might say.
Sure, there is a date printed on your yeast package, but it’s a best-before date, which is entirely different from an expiration date. Think of a best-before date to be like a manufacturer’s freshness guarantee. An expiry date is not the same. It’s a warning not to consume a product because it will likely spoil soon after that date.
Yeast doesn’t spoil to the point of being uneatable because it doesn’t really expire. That’s not a guarantee yeast will still activate the way it should, but it won’t make anyone sick. Yeast is a living organism. If it dies, it’s harmless.
Tip: If you store your yeast in the freezer, make sure to give it time to warm up before use, or give it extra time to proof before deciding it’s not fresh. Yeast makers like Red Star suggest giving your yeast a full hour to warm up before using.
So, when is yeast bad? When it doesn’t look like yeast. Is it grey? Toss it. Is it clumpy? It’s not fit for consumption.
How Long Will My Yeast Stay Fresh?
|Where and How Yeast is Stored||How Long Yeast Will Stay Fresh|
|Open Package of Yeast at Room Temperature||Less than 2 months|
|Open Package of Yeast in Refrigerator||2-4 Months|
|Open Package of Yeast in the Freezer||6 Months|
|Sealed Package at Room Temperature||2-3 Years|
|Sealed or Resealed Package In Fridge||3 Years|
|Sealed or Resealed Package In Sub Zero Freezer||Indefinitely|
Is My Yeast Dead?
I’ve been baking bread on and off for over 15 years, and I’ve never had yeast go completely dead. That is anecdotal, but it’s also been a lot of yeast with sometimes long stints in between uses.
The worst I’ve personally seen is the yeast that has risen bread to three-quarters the height fresh yeast would. That has only happened once. I’d bought the yeast in a small jar quite long before and forgotten about it. Half of the jar was left, and I used what was left to make hamburger buns and dinner rolls to stock up the freezer.
If you think your yeast is dead, proof it before trying a recipe. Proofing yeast that you haven’t used for a while is a good idea, especially if you like recipes that don’t call for proofing beforehand. Most of today’s yeasts don’t require proofing if they’re fresh, so don’t worry about it if you know your yeast is good.
Red Star Yeast has a well-written yeast freshness test you can follow to proof-test your yeast and instructions on how to add your proofed yeast into a recipe that doesn’t call for proofing.
If Your Yeast Is Dead…
If you find yourself in a situation where you don’t have access to yeast, as many did in the spring of 2020, you can try your hand at creating a sourdough starter. Once you learn how to identify a healthy starter, it’s a relatively painless process. Sourdough-focused blog The Clever Carrot has a wealth of information and recipes, including an easy-to-understand beginner sourdough starter method.