Don't throw out that expired dry yeast!

[MaxStout]

This has been brought up from time to time in various threads, but I wanted to add another data point for those who might be hesitant to use an expired packet.

I haven't brewed with liquid in several years. My nearby LHBS closed in 2019, and MW and NB's brick & mortars here closed their doors a few years ago. With the pandemic I went big on internet orders from William's, Brew Hardware, and Ritebrew. So I went solely with dry yeast. No regrets, and I brew beers I like.

Last year, @Bramling Cross was kind enough to send me a couple packets of K-97. They had an Apr 2023 exp date. I kept them in the fridge and finally put them to use yesterday in an "imperial" cream ale. Basically AHA's malt liquor recipe, but with ale yeast.

I rehydrated both packets, adding some nutrients to help it along. After 15 minutes it was proofing nicely in the flask. I pitched it into 5.5 gallons of 1.063 wort and within 12 hours, it went active. It's fermenting nicely now.

My takeaway: Don't toss those packets! Especially if you've taken good care of it, kept it cool, etc.

I've seen posts from people who have successfully used yeast several years beyond its expiration date.

This is just my observation, and I've only used outdated yeast a few times. It's always worked for me. YMMV.

Share your stories--good or bad. What say you re outdated dry yeast?

 

[Pennine]

I have been brewing with 1-3 year old packs I had from a 2 year break in brewing. I rehydrated and usually they are pushing CO2 within 6 hours including a pack of 34/70 and Novalager.

I usually make 14 liter batches.

 

[hilljack13]

I got on a spending spree and have enough yeast to last may years. If you need more K-97 (5 satchets) I have some I would swap or eventually donate. I didn't like it when I used it so now it is just sitting in the fridge.

 

[whoaru99]

Share your stories--good or bad. What say you re outdated dry yeast?

Not brewing yeast, but at the onset of the COVID pandemic we bought a 1lb package of SAF instant baking yeast.

I broke it down into smaller amounts and used Foodsaver to vacuum pack them. Stored in the freezer.

No doubt is well past the original expiry date but still using it and hasn't let me down so far.

Edit: Just checked one of the packages in the freezer. I marked the date (we) packed as 5/11/2020, mfg expiry date 1/2022

 

[Agent]

I bought 30 packs of wine yeast in 2020 that expired at the same time for next to nothing. I've still got half to go, but every one has activated and fermented like it was supposed to.

I'd be curious if there is any actual research showing the degradation in viability for dry yeast.

 

[MaxStout]

Update: That 2-years-past-expiration K-97 I pitched yesterday almost blew the lid off my Brew Bucket tonight. The Cold Crash Guardian I had connected clogged with Krausen (the check valve became fouled). I disconnected it and connected a piece of 1/2" ID tubing straight into the blowoff jar.

I just happened to be near the ferm chamber and noticed no bubbling sound. Glad I caught it when I did. I cleaned up the Cold Crash Guardian and will re-connect it (sans check valve) when fermentation slows down some.

 

[BongoYodeler]

I've only used expired dry yeast a couple times, and each time it was only about a year out of date. In both cases fermentation started and behaved exactly as any non-expired packet of yeast does. I currently have a couple dozen dry yeast packets in my fridge, and no doubt some of them have expired dates. I won't hesitate to use them though.

 

[Hoppy2bmerry]

To this day, I’ve never had an expired dry yeast fail.

 

[shoengine]

Good to know. For what it's worth I used a two year expired liquid yeast, and other than it taking almost a week to build up in a starter, it worked just fine.

 

[BrewnWKopperKat]

I'd be curious if there is any actual research showing the degradation in viability for dry yeast.

IIRC, back in spring/summer/fall of 2020, one of the webinars by Fermentis or Lallemand had a chart. This article (link) from May 2020 may be helpful. This DuckDuckGo search (link) returned some MBAA presentations behind a paywall. This Fermentis presentation (2017, link to PDF) may be of interest.

 

[Northern_Brewer]

The half-life of dried yeast is something over 10 years - I once found some bread yeast that had been kept at ambient temperature at the back of a shelf for 20 years, and it still made bread, albeit with maybe 40-50% of the "rise" of a fresh pack.

 

[Steveruch]

I got on a spending spree and have enough yeast to last may years. If you need more K-97 (5 satchets) I have some I would swap or eventually donate. I didn't like it when I used it so now it is just sitting in the fridge.

What did you brew with it?

 

[Steveruch]

I uśed a Muntons yeast four years past it's best by date in three gallons of best bitter that worked great.

 

[Bramling Cross]

I've used a lot of expired dry yeast and it has always performed as expected...until recently. I was burned by three sachets of Cellar Science CALI earlier this year in a ~1.055 wort. A further sachet of Verdant got the batch going, but all three of those 1-year past expiration CALI sachets were completely dead. Between the miserable performance of Baja and the dead CALI, I won't be buying Cellar Science again. It's not cheap anymore and there are too many excellent dry alternatives that are more reasonably priced at RiteBrew.

 

[hungupdown]

I dry my own harvested yeasts, then freeze in vacuum packed 20g amounts.
I find the occasional pack has expired, or is much slower to start. But think that's probably down to drying temperature control (going too warm).

I always have a fresh (frozen) pack to hand, in case of little activity after 36hr.

 

[jrgtr42]

I dry my own harvested yeasts, then freeze in vacuum packed 20g amounts.
I find the occasional pack has expired, or is much slower to start. But think that's probably down to drying temperature control (going too warm).

I always have a fresh (frozen) pack to hand, in case of little activity after 36hr.

What's your procedure to dry out yeast so it comes back?
I don't brew every week like some on here, and I do tailor the yeast to the brew, so I would like to not have to shell out every time.

I have tried freezing it with glycerine, with about half-and-half results.

As far as the original question goes, I keep my dry yeast packs in the freezer. I brewed a couple weeks ago, I used a pack of kveik yeast that's been there a couple years; I believe it was past expiry, but it was ripping in 24 hours. Other packs of dry have had similar results if I dig into them.

 

[smcinco]

Note the date on the packet. 12yo packet of yeast w 20mins of proofing (admittedly warm water but still phenomenal result).

 

[Pennine]

Note the date on the packet. 12yo packet of yeast w 20mins of proofing (admittedly warm water but still phenomenal result).

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Fermentis makes a very high quality product.

Where was it stores the last 10 years or so?

 

[smcinco]

Fermentis makes a very high quality product.

Where was it stores the last 10 years or so?

Mostly in the fridge but I tossed in the freezer a few years back

 

[Kickass]

Not beer yeast, but I just dry pitched 15g of QA23 (exp. Sep 2023) into a 5 gallon batch cider. It had visible signs of fermentation in 12 hours. I could have probably used 10g, or less.

 

[Closet Fermenter]

I have used expired yeast numerous times; no failures so far. The record is a wine yeast 10 years past expiration, and it worked just fine.

 

[hilljack13]

What did you brew with it?

I did an alt bier kit. To me it just tasted similar to a hefeweizen.