How Long Does Yeast Last? [Active Dry and Instant Yeast]

Got a packet or container of “expired” dry yeast, and not sure if you can still use it? Does yeast expire?

Yeast can be confusing, especially if you’re not an experienced baker.

There’s active dry yeast, instant (or quick-rise) yeast, and fresh yeast (sometimes called cake yeast). And each one works slightly differently.

In this guide, I walk you through the basics of storage, shelf life, proofing (or activating), and expiration of active dry and instant yeast.

Active Dry Yeast vs. Instant Yeast

Dry yeast comes in the form of dehydrated granules.

There are two options available on the market:

• active dry yeast
• instant yeast (or quick-rise yeast)

Both look similar, but there are some key differences you should be aware of.

The main difference between active and instant yeast is that the former needs to be activated (or proofed) before using, while the latter doesn’t. This way, using instant yeast reduces the time needed for your dough to rise before it’s ready for cooking.

Both types of dry yeast are interchangeable – you can use instant yeast if your recipe calls for active dry yeast and the other way around.

The only thing to remember is to proof active dry yeast if you’re substituting it for the instant variety.

The rest, like the shelf life, storage practices, and expiration, are pretty much the same no matter which variety you have.

Does Dry Yeast Expire?

All types of yeast expire at some point. Active dry and instant yeast are dehydrated and, therefore, have a long shelf life of 1 to 2 years and typically keep for a few extra months beyond the printed date. After opening, dry yeast stays active for about 4 months if sealed tightly and refrigerated.

Even though dry yeast granules don’t seem like it, yeast is a living thing that doesn’t stay active forever. Thanks to dehydration, the shelf life of dry yeast is much longer than the 2 to 3 weeks that fresh yeast lasts, but it’s still finite. It’s not like white flour that can last years with only minor quality changes.

Dry yeast usually comes with a best-by date that’s 1 to 2 years from when the granules are packaged. That printed date is, of course, a fairly conservative estimate, so it’s not a stretch to expect to last beyond that date.

How long is yeast good for after the expiration date, then?

As long as your packet of dry active or instant yeast stays sealed and stored in a cool spot, the yeast should stay fresh for 1 to 3 months beyond the printed date. Of course, in some cases, it might expire sooner, so it’s best to proof it to make sure.

Opening the package shortens the storage time of the leftover yeast to only about 4 months. That’s because air exposure further dehydrates the yeast and causes it to lose its leavening power even sooner, even if you store it sealed tightly.

(Different brands might have different recommendations on storage time after opening, so make sure you read the label.)

With that out of the way, let’s talk about using expired yeast.

Can You Use Expired Dry Yeast?

You can use expired dry yeast as long as it activates properly. That’s true for both active dry yeast and instant yeast. So if your dry yeast is a couple of months past its date, proof it before using it in a recipe. You do that by mixing it with warm water and sugar and waiting to see if it foams, which I describe in the proofing section.

If you don’t proof your expired yeast before using it, there’s no guarantee your baked goods will rise the way they should. And you might end up with a flat and dense loaf of bread instead of a nice and airy one.

That said, in some circumstances, you should discard dry yeast. Those include:

• the granules are clumping or forming solid chunks
• any signs of water or any organic growth (e.g., mold) in the package

How to Tell if Yeast Is Still Good?

Checking yeast effectiveness (or proofing the yeast) is pretty similar for both dry and fresh yeast. You only need some warm water and sugar to do it.

Prepare the following:

• 1/4 cup of warm water. If you have a kitchen thermometer, go with 105° to 115°F or 40° to 46°C, which is ideal for the yeast to grow. Otherwise, use warm but not hot water. If your recipe doesn’t use water, use whatever liquid it calls for instead (e.g., milk).
• 1 packet of dry yeast or 2 1/4 teaspoons
• teaspoon of sugar

Then:

• add the sugar to the water and give it a stir
• add the dry yeast and mix everything well
• leave the mixture for at least 10 minutes in a warm spot

It takes between 5 to 10 minutes for dry yeast to activate. If you leave it in a cool spot, it might need even more.

If it’s the middle of winter and your room temperature is on the colder side, consider warming up your oven for like 3 to 4 minutes on low, and proofing the yeast there.

You know that your yeast is activated if it foams up to about 1/2 cup mark. If there’s no foam or froth on top, it’s not potent enough to use. If there’s only a little, give the mixture a couple of minutes more, especially if it doesn’t sit in a warm spot.

Many recipes using dry active yeast have the proofing step built-in. Sometimes, besides the sugar and liquid, the recipe will ask you to add a couple of tablespoons of flour to help activate the yeast. That’s pretty common and works just as well.

Last but not least, you can activate this way both active dry yeast and instant yeast. For the latter, it only makes sense when you’re working with old yeast that you’re not sure is still potent.

How To Store Dry Yeast

Store unopened dry yeast (both active dry and instant) in a cool and dry place, like a cupboard in the kitchen. The fridge and the freezer are viable options too, but not really necessary.

Once you open the package, refrigerate or freeze the leftover dry yeast.

If you’re buying dry yeast in those small single-serving packets, you can simply store them where you keep your spices.

But if you use dry yeast regularly, going with a large container instead of dozens of packets is probably a better approach. If that’s what you do, remember to:

• Seal dry yeast tightly, and with as little air as possible. A freezer bag is a much better option than an airtight container because you can squeeze out all the extra air.
• Place the sealed bag in the fridge or freezer.

Can You Freeze Dry Yeast?

Both dry active and instant yeast last for about 2 years if stored in the pantry, so there’s no need to freeze them. But freezing might be helpful when storing yeast after opening. That’s because it prolongs storage time from 4 months in the fridge to 6 months in the freezer.

The 6 months period is just a general, fairly safe suggestion. If yours sits in the freezer for a few months longer, chances are it’ll still work okay, but make sure to proof it to be safe.

All that said, the 4 months storage period after opening the packet is quite a long one. So unless you buy a big jar, you’ll rarely have to consider freezing dry yeast.

(It’s an entirely different manner for fresh yeast. It lasts only a couple of weeks, so freezing fresh yeast is quite useful.)

How to Freeze Dry Yeast

There’s no special process for freezing dry yeast. You just need to seal the granules tightly (possibly in a bag) and throw them in the freezer. It might help if you label the bag with the freezing date so that you know what you’re working with when you pull it out.

Before using the yeast, give it at least 30 minutes on the counter before using it. This way, it will reach room temperature, and will be able to activate again.