Yeast age vs viability

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chuckda4th

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I was just messing around on yeastcalc.com, and noticed that once yeast gets to be 4 months old, it puts its viability at 10% for at least another 4 months after that.

Is that accurate?

I have some hefe yeast I forgot about in the fridge that was harvested 6/10/12. I was going to toss it, but is it really salvageable with a 3 stage starter like yeastcalc.com says? Just sounds a little far-fetched
 
I think those viability with age factors are kind of "worst case". Stored well and refrigerated yeast seems to keep strong much longer than 4 months in my experience. That said, without lab equipment I can't prove this....
 
chuckda4th said:
I was just messing around on yeastcalc.com, and noticed that once yeast gets to be 4 months old, it puts its viability at 10% for at least another 4 months after that.

Is that accurate?

I have some hefe yeast I forgot about in the fridge that was harvested 6/10/12. I was going to toss it, but is it really salvageable with a 3 stage starter like yeastcalc.com says? Just sounds a little far-fetched
Click to expand...

I made a single stage 1 liter starter of Wyeast 3068 Hefe yeast that sat in my fridge for 10 months the other week and it ate through my 5 gallon batch handily... as long as it's been washed properly and given a decent sized starter you shouldn't have a problem. it actually made the best hefeweizen I've made to date
 
I was rummaging around some earlier posts that dealt with this topic, and the conclusion was Mr. Malty and Yeastcalc tend to underestimate viability. By how much know one really knows. As was said before, kept at consistent refridge temps it should be an issue. I even saw a scientific experiment on washing vs. no washing in terms of storage viability that challenged the conventional wisdom on washing yeast. I believe it was Woodlandbrew who posted it on his blog. Try searching within Google, as I have found the HBT search function not quite as useful.
 
wormraper said:
I made a single stage 1 liter starter of Wyeast 3068 Hefe yeast that sat in my fridge for 10 months the other week and it ate through my 5 gallon batch handily... as long as it's been washed properly and given a decent sized starter you shouldn't have a problem. it actually made the best hefeweizen I've made to date
Click to expand...

Yeah I started harvesting with hefe yeast figuring if it does get a little funky, that works to the style anyway. Haven't yet gone past 1 generation though which I'm thinking will start to open it up even more.

Did you re-harvest that yeast again? I guess if it's alive and hasn't gotten over the top with the flavors, why not?
 
I almost did the same thing and tossed a Wyeast 3522 Belgian Ardennes pack dated 02/2012. Instead, I brewed a simple 1.060 ale 10 months later and used a starter that I stepped up twice over a couple of days -- it was an extremely vigorous fermentation. Although, just because the yeast grows and does its job fermenting out wort, doesn't mean you'll like the flavor of an old yeast. For that I'd say smell it before using it. If you're familiar with the yeast, you'll be able to tell if something is off.
 
chuckda4th said:
Yeah I started harvesting with hefe yeast figuring if it does get a little funky, that works to the style anyway. Haven't yet gone past 1 generation though which I'm thinking will start to open it up even more.

Did you re-harvest that yeast again? I guess if it's alive and hasn't gotten over the top with the flavors, why not?
Click to expand...

yeah, I'm on the 3rd generation of it now... I've found that Hefe yeasts taste better and better as time generations go on. seems to open up a more citrusy taste to them
 
No specific yeast was mentioned, but I was told around the 3rd generation is when yeast "really gets going." I was told that after remarking on the vigorous fermentation I experienced with a 3rd generation yeast. It was an adventure!
 
For a slurry, I would just make a starter (first step of a 2 or 3 step program) and make sure there's at least a decent amount of good cells in there. IME, older yeast (3+ months old) can/will take longer to get going (even in starters, on stirplates). After that first step, though, they act like fresh yeast (mostly because there's a good population of fresh yeast in there now).

Even with the underestimating done by the sites, you're not going to over-pitch the yeast you need. Considering how many cells you'll have post fermentation at least.

I've used 10+ month old vials/packages of yeast before. I just did a 2 or 3 step starter for them. I have some that's over a year old now, that I plan to use with starters. I figure that the first step will tell me if they're ok to use or not. If I get nothing from them after about three days (or 72 hours), I'll probably give them until the following morning to show sign. If nothing, then I'll just toss the small starter and get fresh yeast. Not much of an issue for me.
 
Golddiggie said:
For a slurry, I would just make a starter (first step of a 2 or 3 step program) and make sure there's at least a decent amount of good cells in there. IME, older yeast (3+ months old) can/will take longer to get going (even in starters, on stirplates). After that first step, though, they act like fresh yeast (mostly because there's a good population of fresh yeast in there now).

Even with the underestimating done by the sites, you're not going to over-pitch the yeast you need. Considering how many cells you'll have post fermentation at least.

I've used 10+ month old vials/packages of yeast before. I just did a 2 or 3 step starter for them. I have some that's over a year old now, that I plan to use with starters. I figure that the first step will tell me if they're ok to use or not. If I get nothing from them after about three days (or 72 hours), I'll probably give them until the following morning to show sign. If nothing, then I'll just toss the small starter and get fresh yeast. Not much of an issue for me.
Click to expand...
Same story here. I do it all the time because the outdated yeast is 1/2 price at the LHBS
 
I want to use yeast that's about 10 months old and "washed" per the sticky. Is there a certain smell that says it's no good? Silly question, I know; but I thought somewhere in that long sticky, weird smells were mentioned. I'm not sure what to "look" for. I think it's fine, but I'm looking for more info before I use it.
 
hope2perc said:
I want to use yeast that's about 10 months old and "washed" per the sticky. Is there a certain smell that says it's no good? Silly question, I know; but I thought somewhere in that long sticky, weird smells were mentioned. I'm not sure what to "look" for. I think it's fine, but I'm looking for more info before I use it.
Click to expand...

Think of what the yeast smelled like when new/fresh. Think back to how it smelled when you put it into the jars. If it smells like either of those (or close to it) then you're good. If it smells like a thousand dirty asses all taking a dump at the same time, while eating durian and belching, I'd not try it. :eek:
 
Not sure it smells like dirty asses.... :D That's funny. I might try stepping it up a bit. Decided to brew Tues instead of today, so I have time to buy fresh yeast if I decide not to go with this. Thanks for the description Golddiggie. :)
 

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