Yeast Expiration Dates

If you're like me you want to make sure that your beer is made from the absolute freshest ingredients available to you. This also goes for the yeast used to ferment those ingredients into a highly drinkable beer, it has to be viable in order for it to convert enough of the fermentable sugars. For some reason or reasons unknown to me the manufacturers of yeast seem to go out of their way when it comes to printing expiration dates on the yeast they package.

Does anyone have expiration date information for yeasts other than Wyeast, Fermentis and Danstar that they would like to share?



Yeast Expiration Dates

White Labs dates their yeast too. I ignore them anyway.

I rarely use dry yeast, but if kept in the refrigerator, it will last years, with very little loss of viability; it's heat that deteriorates it. The dates are probably for yeast kept at room temp.

With liquid yeast I always make a starter and provide plenty of time in case there are not too many viable cells. I've never done it, but I suspect that liquid yeast kept refrigerated, could still be revived after a few years.

I disagree. I think that time seriously cuts down the viability of yeast.

How many threads have you read on here where people have had trouble with smack packs that are 6 months old? They're usually the same: "I smacked it and 3 hours later there was no inflation. I pitched it anyways and haven't seen activity in 36 hours."

I do agree that it's not likely that ALL the yeast will die and you can eventually make enough starters to get the pitch rate you want. But the older it is, the more steps or bigger starter you have to make.

In terms of liquid, iIf you're stepping up a starter, then the age of a yeast isn't really an issue.

Bobby M did a test on year old stored yeast here; https://www.homebrewtalk.com/f13/testing-limits-yeast-viability-126707/

And my LHBS cells outdated tubes and packs of yeast dirt cheap 2-3 dollars each and I usually grab a couple tubes of belgian or other interesting yeast when I am there and shove it in my fridge. and I have never had a problem with one of those tubes.

I usually make a starter but I once pitched a year old tube of Belgian High Gravity yeast directly into a 2.5 gallon batch of a Belgian Dark Strong, and after about 4 days it took off beautifully.

With any stored, old yeast you just need first to apply the "sniff test" if it smell bad, especially if it smells like week old gorilla poop in a diaper left on the side of the road in the heat of summer.

Then make a starter, and if it takes off you are fine. The purpose of a starter is to reproduce any viable cells in a batch of yeast....that;s how we can grow a starter form the dregs in a bottle of beer incrementally...and that beer may be months old.

Even if you have a few still living cells, you can grow them....That's how we can harvest a huge starter (incrementally) from the dregs in a bottle of some commercial beers. You take those few living cells and grow them into more.

If yeast can be grown from a tiny amount that has been encased in amber for 45 million years, 45 million year old yeast ferments amber ale we really don't need to sweat too much about how old a yeast is, if it's properly stored.

we just need to think in terms of making starters. Viability isn't really an issue if you are reproducing a lot of healthy cells. Which is what you are doing when you make a starter.....

Really even with "old yeast" if there is a few cells, they will reproduce.

kanzimonson said:

How many threads have you read on here where people have had trouble with smack packs that are 6 months old? They're usually the same: "I smacked it and 3 hours later there was no inflation. I pitched it anyways and haven't seen activity in 36 hours."

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ANd in reality even if the pack is a day old, inflation doesn't really matter on bit.

From the horse's mouth.

From the Wyeast FAQ website:

3. Does the package need to be fully swollen before pitching?

No, The package can be pitched before activating, or at anytime during the activation process. The activation process "jump starts" the culture's metabolism, minimizing the lag phase.

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And again, if you make a starter you reproduce the viable cells, and they will usually eat the dead ones, just like if you added yeast to the boil as a yeast energizer. They are cannibals.

When we bottle harvest yeast, we are growing yeast that is god knows how old and stressed to high heaven, and yet with careful feeding we manage to rescue it. Why would an old smack pack or tube be any different? You grow what is still alive.

Revvy said:

You grow what is still alive.

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Stop it
https://www.homebrewtalk.com/f163/stop-bashing-my-yeast-friends-192944/

I'm pretty lucky. I live in San Diego (also the home of White Labs) and every time I buy a vial from my LHBS its always fresh, i've even gotten a few Vials that were packaged the day before! (White labs dates their vials 3 months from date of package IIRC, so just subtract three months from the expiration date to see when it was packaged) I've never had a problem with a single vial and I always straight pitch them, I never make starters.

kanzimonson said:

I disagree. I think that time seriously cuts down the viability of yeast.

How many threads have you read on here where people have had trouble with smack packs that are 6 months old? They're usually the same: "I smacked it and 3 hours later there was no inflation. I pitched it anyways and haven't seen activity in 36 hours."

I do agree that it's not likely that ALL the yeast will die and you can eventually make enough starters to get the pitch rate you want. But the older it is, the more steps or bigger starter you have to make.

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Yeah, I would have to agree with this based on my experiences with Wyeast smack packs although I will say that it also depends on which strain and the age of that particular strain or pack. I have taken 6+ month old Pac man smack packs and created a starter that took off like crazy. This past week I attempted to use a Thames II Private Collection pack which was dated Feb. 10 and it was DOA on the stir plate after 24-36 hours. This was the only time that I have not been able to get a smack pack to work. I did my standard 2000 ml starter which has always worked well in the past. Montanaandy

I've only bought an old smack pack once (Apr 2010, purchased about 3 weeks ago) because it was like 3 dollars. I built up a good sized starter from it and pitched it and had the highest krausen I've ever seen. I'm pretty sure that it's hit or miss, but as long as you make a starter then you should have more luck than just pitching a questionable vial/pack.

kanzimonson said:

I disagree. I think that time seriously cuts down the viability of yeast.

How many threads have you read on here where people have had trouble with smack packs that are 6 months old? They're usually the same: "I smacked it and 3 hours later there was no inflation. I pitched it anyways and haven't seen activity in 36 hours."

I do agree that it's not likely that ALL the yeast will die and you can eventually make enough starters to get the pitch rate you want. But the older it is, the more steps or bigger starter you have to make.

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It sounds like you agree with me; "it's not likely that ALL the yeast will die and you can eventually make enough starters to get the pitch rate you want". I've never directly pitched a liquid yeast except as a slurry, I always use a starter and get a good pitch rate.

Montanaandy said:

This past week I attempted to use a Thames II Private Collection pack which was dated Feb. 10 and it was DOA on the stir plate after 24-36 hours. This was the only time that I have not been able to get a smack pack to work. I did my standard 2000 ml starter which has always worked well in the past. Montanaandy

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Now I'm concerned. I have a pack of Thames II I am planning to use in the next couple of weeks; dated 01Feb10. I guess I had better smack it early and feed slowly.

I think it's time I learned how to make a yeast starter. Any good information you can point me to is much appreciated...

ScrewyBrewer said:

I think it's time I learned how to make a yeast starter. Any good information you can point me to is much appreciated...

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You mean like this?

How to make a yeast starter - Pictorial How to make a yeast starter - Pictorial

I don't know why people don't make starters. It's really not that hard, and I think that it's fun to get to watch fermentation going on twice for the same brew.

Maybe I'm just a nerd and like doing anything beer related.

Revvy said:

You mean like this?

How to make a yeast starter - Pictorial How to make a yeast starter - Pictorial

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Thanks Revvy I've read and bookmarked that thread, it's really helpful. Do you use a stirplate, or is that overkill?

I've only had problems trying to make refrigerated, washed yeast take off. After a few months it takes a lot of coaxing to get them going, even in a starter. I've never had a problem with unused yeast.

I use one because I got one for free, but it isn't necessary. Plenty of starters have been made for decades before anyone ever got the idea for using one in brewing.

Any good sources for a 5L flask? That's the only thing currently stopping me from making starters.

I agree that it doesn't always work to use outdated packages. I had bought 2 Smak Paks that were dated Feb 2010 one Munich Lager and one Budvar. I made a starter and tried to get the Munich up and going. No go. I pitched the Budvar and it took off. Some strains may be more viable than others for longer periods of time.