Used 5 year old liquid yeast successfully

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abw73

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A few years back a homebrew shop was selling a variety of expired Wyeast smack packs dated 2016 and 2017. They were about a year old when I bought them. When I researched using old liquid yeast, many threads discussed 6 month old yeast as beyond ancient, and some went as far as 2 years, suggesting that was stone age. Most said don't use it and get fresh yeast. Some I read involved a recently expired smack pack being thrown out without even testing to see it was viable.

The pack I had was made in fall 2016 and used in early August 2021. Smacked it, took about 5 days to fully swell at room temperature. Because of its age, I stepped it up to increase viability and cell count. I made a starter, let it sit on the stir plate about 24 hours, the next day I made another starter, and added that to the existing starter, and let it stir for another 24 hours. I pitched it after about 48 hours.

Airlock was bubbling within 24 hours. I let the beer stay in the fermenter almost a month. Made a nice krausen ring. Beer turned out fine, about 5% ABV, and has plenty of flavor. No off flavors were detected.

Yeast remained refrigerated before using. And there you go. Smack pack from 2016 finally used 5 years later. It fermented fine with proper care and a starter.

For those wondering, it was 3726 and I brewed a saison.
 

rtstrider

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I got 2 expired packs of Omega Hothead for free from a local store 3 years ago or so. They were each a year old. I pitched both packs into 500 ml 1.020 wort on the stir plate and they tore right through it. From there it was 1L 1.020 and 2L 1.040. I still have that yeast banked up after a few batches and various overbuilt starters. After about 2 years I moved it from a slurry in the fridge and banked it up in distilled water/glycerin in a test tube. It's part of the freezer yeast bank now
 

Dr_Jeff

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I used a pack of US-05 that was ~5 years old, while I had it, it was always kept refrigerated.
It did not start, nothing after 36 hours, pitched a fresh pack and it was going in 4-6 hours.
 

IslandLizard

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Similar experiences here.

A few weeks ago I successfully revived 5-year old slurries from overbuilt starters. They were stored in small 4 and 8 oz mason (jelly) jars in the fridge. Took about a week to get them nice and creamy. After cold crashing I got 1/2" - 3/4" layers of yeast in my 1/2 gallon pickle jars. So old age is not always detrimental, at least when it comes to yeast. ;)

Yeast in question: ECY03 (East Coast Yeast - Farmhouse Blend)
 

Spikybits

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Yep - I store in Jelly Jars as well. Enough jars I get those looks from the wife when she gets beer out of the fridge....

My oldest - WLP001 and Voss K are several years old now. I do not use starters - 1 sanitized spoonful and were off to the races within 24hours. I do make starters to repopulate the jars when my colonies run low :)

whenever i buy online - i always buy expired packs, some retailers do as a grab bag, others let you choose from the expired. never had a dead one
 

IslandLizard

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I do not use starters - 1 sanitized spoonful and were off to the races within 24hours.
You're just adding 1 tablespoon of yeast slurry to a 5 gallon batch, without making a starter? How old is that stock in the jelly jar?

Enough jars I get those looks from the wife when she gets beer out of the fridge....
I have a few (small) boxes holding 12-24 jars each. They're less susceptible to temp variations that way and getting knocked over. I just slide the boxes between shelves, they just fit. I'm in the process of consolidating them to a) save space and b) refresh the slurries with new starters.

Now I practically own the kitchen, do most of the cooking, and brew in there too, so I probably can get away with quite a bit more than most husbands would.
 

Spikybits

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You're just adding 1 tablespoon of yeast slurry to a 5 gallon batch, without making a starter? How old is that stock in the jelly jar?


I have a few (small) boxes holding 12-24 jars each. They're less susceptible to temp variations that way and getting knocked over. I just slide the boxes between shelves, they just fit. I'm in the process of consolidating them to a) save space and b) refresh the slurries with new starters.

Now I practically own the kitchen, do most of the cooking, and brew in there too, so I probably can get away with quite a bit more than most husbands would.
I own the beer fridge so i occupy the untouchable self :) - i think im at 14 jars all neatly lined up

yes suppose you can say 1 TBS for a 4g batch - leave headspace in my kegs - serve and ferment in same keg

I estimate the bottom of the jar for WLP001and Voss K are turning 4 in January. at 4-5g batch range, IMO I think you have to go out of your way to underpitch but I am not a scientist
 
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abw73

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I used a pack of US-05 that was ~5 years old, while I had it, it was always kept refrigerated.
It did not start, nothing after 36 hours, pitched a fresh pack and it was going in 4-6 hours.
That's interesting you mention this. Back in February I posted a thread about using 5 year old dry yeast successfully.

 

IslandLizard

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I estimate the bottom of the jar for WLP001and Voss K are turning 4 in January.
That sounds quite old for a direct pitch! But if it works, they may be much more resilient than we are meant to believe they are.
Now Kveiks are quite hardy, so they may have better chances.

My WLP820 (Oktoberfest) took a long time and 4 steps to generate a pitchable amount with enough to spare. The sleeve was 3 years old. ;)
 

Spikybits

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If scientists can propagate yeast from pottery scraps from BC, yeah I would agree with yeast being hardy - my concern would be if wild yeast were to contaminate wort, old yeast may not be fast/vital enough to out compete.

Now when i get low in the jar - i build up a starter, and decant. pouring concentrated slury into the jar. i do build up 2 or so steps from the pack/jar to populate my library jar again. typically the yeast is between the 2 and 3oz line on the jar when the slurry settles and the starter beer is clear in the library jar. you can sometimes clearly see the line between the fresh generation and the older generations - like a layer cake. i scoop through to the bottom so different generations get pitched together. It much easier to handle the caky yeasts vs the viscous yeasts.

I just got Lithuanian farmhouse and that stuff is extremely liquid - a pain to get a decent amount out with a spoon, just washes away - took me 3 scoops to get what I think is a tablespoon out.

i store yeast under its own starter beer so I think of it as its in some sort of deep sleep just waiting for a nip of sugar
 

Bobby_M

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I don't think anyone would say that a years old pack of yeast is completely dead in 100% of the cases but the viability very well could be zero on a pack that old. At most it's got a couple billion viable cells. You can get that up to acceptable colony in a two step like you've done. The only way to know if there's anything alive is to do a cell count or just try it in a starter. It's always fun to see what you can get away with for science, but I assume most people brewing have the means to spend $7 on a fresh pack of yeast considering all the time and money that goes into the rest of the batch.
 
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abw73

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It's always fun to see what you can get away with for science, but I assume most people brewing have the means to spend $7 on a fresh pack of yeast considering all the time and money that goes into the rest of the batch.
Well, cost had nothing to do with my experiment. Before I did this, I read numerous threads here and other brewing sites regarding expired yeast, and the most common answer by far was, the yeast is too old, probably not viable, throw it out. Some said a new smack pack is $7 so why risk it?

It seemed the overwhelming majority of people didn't even try it, just threw out the old pack and bought another. I wanted to try it.

Reminds me of a saying I read somewhere: everybody says it's not possible (whatever it is) until someone actually does it, then everybody is like "oh wow it IS possible!"

I realize I'm not the first to revive expired yeast, but I could not find a single thread regarding 5+ year old liquid yeast. The absolute oldest I could find in my searching was 2 years.

Anyway, just sharing my results.
 

Kickass

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I think the reason people suggest tossing is not so much because it’s not possible but more so because it’s not worth the cost and effort. My guess is that not many are willing to science this cause as you were. Thanks for sharing your results.
 

BrewnWKopperKat

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Well, cost had nothing to do with my experiment.
For many people who brew, time is a "cost". They want to make good beer. They are willing to spend money to achieve that goal.

With both your dry yeast and liquid yeast "experiments", you have made some valid points - that there are ways to make use of out dated yeast.

If, in addition, you choose to "challenge the conventional wisdom" with statements like " It seemed the overwhelming majority of people didn't even try it " and " Reminds me of a saying .... ", it is plausible that people will just walk away without remembering your primary point.

That being said, thanks for sharing the results of using old yeast (both liquid and try).
 

Miraculix

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I had a Pack of expired lallemand abbeye, which never took off. It can go this way and that way... Key is, make a starter. Also with expired dry yeast.

I didn't :D
 

dtashmore547

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never tried to revive old yeast but my information is that the yeast has a dormant stage and it can take a while for it to reactivate once in this state, not sure it it will return with exactly the same characteristics once reactivate, would be an interesting experiment though to make a starter and go through careful sterilisation to see what transpires.
 

bwible

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I owned a homebrew shop for a few years in the early 2000s. It happened every so often when I would clean out the fridge or do inventory I would find an old smack pack that fell behind something. I would always smack them for fun and they always swelled up. The oldest one I ever did it with was about 2 years old.
 

TBA

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Question about generations. I over build and save in jar. I step it up, pitch most and save the over build. Does each of these buildups count as a generation? How many generations can you go? I’ve gone 5. Usually by then I am trying out a new yeast. I guess I could save the yeast longer but after a couple months I figured it was too old.
 

balrog

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I will add that the older the yeast I use, it seems to take longer to stir up the 1,2 or 3 step starter. Longer to wake up. Lag times in the batches are marginally longer but the time for the starter to get going was noticeable.

EDIT, just saw the generation post. I have gone 8. Something always happens. The yeast changes, gets a layers of purpleish gack on top, changes from being little krausen in batch to huge krausen and blow off, smells of vinegar poured on the underside of a muddy yak.

I blame my careful but not careful enough sanitary procedures. But 6 to 8 is fairly easy to do, and I call each use/overbuild, a generation.
 

balrog

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Been repitching the same WY1469 for close to 7 years... and the first pitch was grown via stepped starters starting with a smackpack that had been frozen!
At this point, due to environment/mutation, you most definitely have a unique house strain of WayWayWayWestYorkshire ale yeast.
 
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