2 years
Unopened dry yeast, cool and dry, until the date (NDSU, Red Star)
3 to 4 months
Opened dry yeast, airtight, back of the fridge (Fleischmann's, Red Star)
Up to 6 months
Opened dry yeast, airtight; makers disagree on freezing (NDSU)
The short version: keep sealed dry yeast somewhere cool and dry, and use it by the date on the pack, about 2 years from packing. Once opened, seal it airtight and keep it cold, then use it within 3 to 4 months. When in doubt, proof it first, because dead yeast looks exactly like live yeast.
Storage times here come from Red Star Yeast, Fleischmann's Yeast and the NDSU Extension food storage guide. The proofing test also comes from University of Arkansas Extension.
On this page
What should you check when you buy yeast?
Check the date first, because yeast is one of the few pantry staples that carries a real one. Clemson Cooperative Extension lists yeast among the foods with expiration dates, meaning the last day the product should be used. So buy the pack with the most distant date, and buy only as much as you will bake through.
A sealed pack with the most distant date.
A distant date and a sealed, undamaged pack.
A distant date. Red Star Yeast stamps its jars with a best-if-used-by date 2 years from packing. So a pack with only weeks left has already used most of its life.
A sealed, undamaged pack. Fleischmann's says oxygen, heat and humidity all decrease the activity of yeast. That is why a torn or puffy packet is a poor buy.
The right size for your baking. Once opened, yeast has only months rather than years, so a big jar suits a weekly baker. Otherwise, single packets waste less.
The right type for the recipe. Fleischmann's says its instant yeast loses its fast-rising ability if dissolved in liquid first. So read the recipe before you swap one kind for another.
How to store yeast so it lasts
To store yeast so it lasts, keep it cool, dry and sealed away from air. Heat, damp and oxygen are what wear it down, so each one you shut out buys it more time.
Where should you store unopened yeast?
Unopened dry yeast keeps in a cool, dry pantry until its date, according to Red Star and Fleischmann's. Red Star stores unopened jars at room temperature, away from heat sources. It also allows the fridge or freezer for unopened jars, although neither is required. University of Arkansas Extension gives the same rule: keep yeast away from high heat and moisture. So a cupboard away from the stove and the kettle is the right shelf.
Sealed yeast in a cool, dry cupboard, away from the stove.
Sealed yeast in a cool, dry cupboard, away from the stove.
How long does yeast last?
Unopened dry yeast lasts about 2 years, according to the NDSU Extension food storage guide. Red Star agrees, since its best-by date sits 2 years from packing. Once opened, however, the clock is much shorter. NDSU gives opened dry yeast 4 months in the fridge, and Fleischmann's says to use it within three to four months. Red Star also gives opened jars and opened packets 4 months. So treat 3 to 4 months as the opened limit, and check your own pack in case it says less.
So the date matters while it is sealed, and the opening day matters after that. Write that day on the jar, as Red Star advises.
Should you store opened yeast in the fridge?
Yes, opened yeast belongs in the fridge, sealed airtight, according to Fleischmann's and Red Star. Fleischmann's puts it in an airtight container at the back of the fridge, away from drafts. Red Star goes further, because it says opened jars must be stored in the fridge or freezer. For an opened packet, Red Star folds the top over to the level of the yeast and clips it shut. Then the cold slows the yeast down, while the seal keeps out the damp and the oxygen.
How do you store fresh yeast?
Fresh cake yeast lives in the fridge, and it lasts weeks rather than months. Fleischmann's says fresh yeast should be refrigerated, unlike packaged dry yeast. It also says fresh yeast is best used within several weeks of purchase. So buy fresh yeast for a bake you have planned, rather than to keep.
Does yeast go bad?
Dry yeast does not rot like fresh food, but it does die. Fleischmann's says yeast loses its potency as it ages, which shows up as longer rising times. Eventually it stops working altogether. Dead yeast also looks exactly like live yeast, so the date and the proofing test are the only reliable checks. That is also why the self-rising flour guide treats its leavening the same way.
Can you freeze yeast?
Dry yeast can be frozen for up to 6 months, according to the NDSU Extension food storage guide. However, the yeast makers disagree on whether you should. Red Star Yeast prefers the freezer for opened jars. On the other hand, Fleischmann's Yeast says freezing is not recommended. So follow the maker of the yeast you bought, and use the fridge when the pack says nothing.
How do you freeze yeast?
Seal the opened yeast in an airtight jar or a folded, clipped packet, then freeze it. Red Star labels the jar with the day it was opened. It also says dry yeast will never freeze solid, so you can scoop it out frozen. Before you use it, however, Red Star takes out only what you need and lets it come to room temperature for 20 to 30 minutes. Then the rest goes straight back in, before it can gather any damp.
Airtight, dated, and only a spoonful out at a time.
Airtight, dated, and only a spoonful out at a time.
Can you freeze fresh yeast?
No, according to Fleischmann's, which tells you not to store fresh yeast in the freezer. Fresh yeast is a moist cake rather than dry granules, so it behaves differently. So keep fresh yeast in the fridge, and use it within the several weeks Fleischmann's gives it.
How long does frozen yeast last?
Frozen dry yeast lasts up to 6 months, according to the NDSU Extension food storage guide. Red Star, however, gives opened yeast 4 months whether it sits in the fridge or the freezer. Since the shorter figure costs you little, treat 4 months as the target and 6 as the edge. After that, proof it before you trust it.
How to tell if yeast is still good
Yeast rarely shows its age, so you cannot judge it by eye. Instead it fails in stages: first it slows, then it barely foams, then it does nothing. Damp is the other enemy, because it wakes the yeast up too early. So here is what each stage means, and the 10-minute proofing test that tells you which one you have.
Verdict: use it
Dry, free-flowing yeast
Loose, dry granules that pour freely, inside the date and sealed since you opened them. Red Star and Fleischmann's both treat that as yeast in its prime, so this yeast goes straight into the dough.
Verdict: proof it first
Yeast past its best-by date
The granules look fine, but the pack is past its date. Fleischmann's says yeast loses potency as it ages, so the rise takes longer. It may still work, though. So proof this yeast before you commit flour to it.
Verdict: proof it first
Damp or clumped yeast
Granules stuck together in lumps, often in a pack that was not sealed. Fleischmann's says humidity decreases the activity of yeast, and Arkansas Extension keeps yeast away from moisture for the same reason. Clumped yeast has met damp, so proof it before you use it.
Verdict: use more time, or replace it
Yeast that foams only weakly
In the proofing test the mixture bubbles, but it never reaches the half-cup mark. Fleischmann's counts yeast as active only when it foams to that mark in 10 minutes. Weak yeast can still raise dough slowly, since Fleischmann's says aged yeast simply means longer rising times. For a recipe that matters, though, buy fresh yeast.
Verdict: throw it out
Yeast that does not foam at all
After 10 minutes the water is flat and cloudy, with the granules sunk to the bottom. Red Star says yeast that fails its test should be discarded. No amount of extra time will bring this yeast back, so throw it out and open a new pack.
How do you test if yeast is still active?
Proof it in warm sugar water for 10 minutes, following the test Fleischmann's and Arkansas Extension describe. Stir 1 teaspoon of sugar into ¼ cup of warm water at 100 to 110°F. Then stir in one packet, or 2¼ teaspoons, of dry yeast. If it foams to the ½-cup mark within 10 minutes, it is active. Instant yeast loses its fast rise once dissolved, however, so Fleischmann's says it then needs two full rises.
Yeast substitutes
Out of yeast, or did yours fail the test? Then one of these will rise a different kind of bake.
Substitute
Works best in
What changes
Sourdough starter
Slow-rise loaves
Wild yeast, so plan on a much longer rise.
Buttermilk and baking soda
Soda bread and pancakes
The acid reacts with the soda, so bake it straight away.
Baking powder
Muffins and flatbreads
A quick rise, but never the chew of a yeast loaf.
Mistakes people make when they store yeast
These are the ways people store yeast that cost them a loaf, so each one has an easy fix.
Leaving an opened packet folded loosely in the cupboard. Red Star folds it to the level of the yeast, clips it shut and keeps it cold.
Keeping it beside the stove or the kettle. Arkansas Extension says yeast must be kept away from high heat and moisture.
Scooping from a cold jar with a wet spoon. Fleischmann's says humidity decreases the activity of yeast.
Forgetting when it was opened. Red Star asks you to write the opening date on the jar and use it within 4 months.
Freezing fresh cake yeast. Fleischmann's says not to store fresh yeast in the freezer.
Trusting old yeast without a test. Fleischmann's says it loses potency with age, so proof it for 10 minutes first.
Dissolving instant yeast in water before a quick bake. Fleischmann's says instant yeast then loses its fast rise and needs two full rises.
Sources
Red Star Active Dry Yeast 4-ounce jar, Red Star Yeast, on storing unopened jars at room temperature, opened jars in the fridge or freezer for 4 months, a best-by date 2 years from packing, and discarding yeast that fails its test.
Red Star Quick-Rise Instant Yeast Packets, Red Star Yeast, on folding an opened packet to the level of the yeast, clipping it and keeping it cold.
Frequently Asked Questions, Fleischmann's Yeast, on oxygen, heat and humidity, opened yeast in the fridge for three to four months, freezing not being recommended, and the 10-minute proofing test.
Yeast 101, Fleischmann's Yeast, on sealed dry yeast lasting about two years, refrigerating fresh yeast, using it within several weeks, and never freezing it.
Food Storage Guide FN579, Julie Garden-Robinson, NDSU Extension, reviewed January 2023, on dry yeast keeping 2 years in the pantry, 4 months opened in the fridge and 6 months frozen.
Is my yeast still good?, JoAnn Vann, University of Arkansas Cooperative Extension Service, on keeping yeast away from high heat and moisture and Utah State's 10-minute foam test.
Food Storage: Pantry, Clemson Cooperative Extension factsheet HGIC 3525, revised March 2020, on yeast carrying expiration dates.
Storage times and safety advice on this page come from the sources above. Food safety depends on conditions I cannot see, so read the Disclaimer, and if in doubt, throw it out.
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