How long will dry yeast last in the fridge?

[Miltonboro]

I'm just getting back to brewing after a 10yr break and have had an assortment of dry yeasts in my fridge the entire time, mostly Fermentis and Lallemand. As well as pellet hops vacu-sealed in the freezer and DME in sealed buckets. Just started four beers using Fermentis S-04 and K-97, and Lallemand Munich Classic, and Munich Wheat(discontinued it seems). I pre-hydrated all four before pitching as I always have, and all four were beginning krausen in under six hours and all had full krausen in under 24hrs. All indistinguishable from new dry yeast packets to my eyes. I'd have to assume they'd be viable well past 10yrs based on this. Has anyone used even older dry yeast?

So IMHO if one is inclined to stock up with a collection of dry yeasts I wouldn't hesitate to over shelf life concerns.

 

[mac_1103]

Nice. I've never worried about expiration dates on dry yeast, but I can't say I've ever gone anywhere near ten years either.

 

[hiphoppotamuss]

Wow! Definitely let us know how they turn out!!

 

[dmtaylor]

I haven't used any THAT old but several times used some that was maybe 5 or 6 years old, without problems. Maybe dry yeast will last for 50 years if unopened in a tight vacuum sealed or nitrogen filled packet (who knows how long).

After opening, I have found that it does degrade over time, maybe only lasts 12-18 months after opening before it really loses significant viability.

 

[PCABrewing]

After opening, I have found that it does degrade over time, maybe only lasts 12-18 months after opening before it really loses significant viability.

Being opened (damaged packet) was one of the attributes of the informal test I conducted previously. That packet was 6+ yrs. old but had been damaged in shipment. It started to develop krausen but I cannot say what the viable cell count was though it looked normal.
My biggest concern with the damaged packet was potential contamination (not necessarily other yeast).

 

[dmtaylor]

Being opened (damaged packet) was one of the attributes of the informal test I conducted previously. That packet was 6+ yrs. old but had been damaged in shipment. It started to develop krausen but I cannot say what the viable cell count was though it looked normal.

That's your luck, then. Because I have had opened packets that I discovered with subsequent batches were completely dead just a year or two after opening.

 

[PCABrewing]

That's your luck, then. Because I have had opened packets that I discovered with subsequent batches were completely dead just a year or two after opening.

I did store it in a ziploc snack bag in the refrigerator but agree luck surely played a role. I wouldn't have risked a batch on it.

 

[Snuffy]

Let's just hope yeast is all you awaken from the long, cold slumber. You ever seen "The Thing" with Kurt Russell?

That is very cool tho. Yeast is amazing stuff.

 

[Hoppy2bmerry]

I don’t. Think I’ve used 10 year old packets of dry yeast (yet), but I have a small glass jar of baker’s dry yeast in the fridge that I bought at a reduced price because it was nearing its best by date, and it’s still fine. The jar has been opened and closed many times it’s likely 8-9 years that I’ve had it.

 

[madscientist451]

I found an old Mr beer kit at goodwill, the date codes showed it was 7 + years old. I made the kit and the yeast worked ok with no refrigeration all that time.

 

[Rockman]

I've used some 10+ year old EC1118 that fired right up.

That being said, I've had non expired Nottingham be dead.

 

[Miltonboro]

I suppose Lallemand has the advantage of being vacu-sealed so you know is the seal is broken.

 

[SFC Rudy]

I brewed a Pilsner yesterday. Pitched two packets of 34/70 that expired August 2024. Had activity six hours later.

 

[Miraculix]

That's your luck, then. Because I have had opened packets that I discovered with subsequent batches were completely dead just a year or two after opening.

Same for me.

 

[VTMongoose]

Since I moved to North Carolina I've switched to using more dry yeast.

Sunday I re-brewed my Belgian Golden Strong. I had gotten a packet of expired WLP570 from Atlantic Brew Supply for free just before they closed, it was produced in August of 2024 I believe. On paper should have been ~75B cells, pitched Sunday evening. Yesterday evening, 24 hours later, there was zero evidence of activity. Hit it with a packet of WB-06 (same strain) and this morning it was ripping away.

The first time I brewed this beer, I used a packet of WB-06 that expired two years prior and likewise it took off within 12 hours.

White Labs' product is not a "bad" product per se. I used a fresh packet of WLP575 in a Belgian Blonde one month ago and even direct pitching it without using a starter, it was ripping away in less than 12 hours. When these packets are fresh, they are a HUGE pitch for sure, but they are way too expensive, and the viability just drops off a cliff after 4-6 months even kept refrigerated.

Everyone I know that doesn't have access to a local homebrew shop is moving away from liquid and towards dry yeast. I hope we see the homebrew manufacturers continue to create more dry versions from their yeast bank because I feel that of the say 20 or so liquid pitches I used in 2024, only about half of them had any viability despite most of them being within expiry, most of which I personally transported to my house in a cooler from the cooler of the LHBS.