Reusing a clearly mutated yeast -- bad idea, or terrible idea?

[Hoochin'Fool]

I made a batch of pale ale early this summer that I fermented with a 3rd generation of S-04. Unlike the previous brews, where gravity went from 1053 -> 1011, this one went from 1055 -> 1006. At bottling time, I was not sure if the beer would be any good or not, so I just dumped the yeast cake after bottling. I did however, get lots of trub (deliberately) in the last two bottles (labeled as such), so if the beer turned out great, I could probably still resurrect whatever this yeast was. Well, as it turned out, the beer was great, and there were no gushers, no weird flavors, nothing out of the ordinary. The citra dry hop aroma is mostly gone, but flavor is still very nice.
But now, I'm down to just those last two trubby bottles, and wondering if I should try making a starter to keep this yeast going, or not tempt fate, and just be grateful that I didn't have to dump the batch.

A subsequent batch using same bucket/spigots/etc made with a new packet of S-04 fermented perfectly normally (1054 -> 1012), so I think that rules out infected equipment.

 

[mashdar]

I'd go for it, but I harvested LAB from my kitchen scraps bin.

 

[IslandLizard]

I'd cultivate that yeast from the trub in those 2 bottles. Make a starter with it and evaluate (that's is your first stage).

If it is what you want/expect, then grow more to do a small 2-3 gallon batch, while keeping some of the "first stage" yeast behind as a backup, just in case.

Instead of a mutation, it could very well be a lucky infection (more likely).

 

[madscientist451]

Go for it and run a small, one or two gallon batch to try it.

 

[Hoochin'Fool]

I'd cultivate that yeast from the trub in those 2 bottles. Make a starter with it and evaluate (that's is your first stage).

I've got some free time on Thursday to make some wort for a starter. Not sure how I should evaluate whether it's going to be good or gross. Just smell/taste?

Instead of a mutation, it could very well be a lucky infection (more likely).

That does seem more likely than S-04 suddenly gaining 89% attenuation (I may be calculating that wrong for 1055 -> 1006)...

 

[IslandLizard]

That does seem more likely than S-04 suddenly gaining 89% attenuation (I may be calculating that wrong for 1055 -> 1006)...

That calculation is correct, 89% attn, for 6.4% ABV. (Brewer's Friend - ABV Calculator)

 

[Snuffy]

I'd go for it, but I harvested LAB from my kitchen scraps bin.

I remember that thread. That was awesome.

 

[betarhoalphadelta]

I'd go for it, but I harvested LAB from my kitchen scraps bin.

Avatar checks out.

 

[betarhoalphadelta]

But now, I'm down to just those last two trubby bottles, and wondering if I should try making a starter to keep this yeast going, or not tempt fate, and just be grateful that I didn't have to dump the batch.

If the beer turned out great, why not give it a go? Yeah, worst case you end up wasting a batch of beer. Best case you have a proprietary new yeast that makes AMAZING beer that you'll get Wyeast and White Labs into a bidding war to buy from you for $$billions!

 

[sibelman]

Just wondering, having no experience with such things:
If this is a "lucky infection" with some bacterium (rather than a wild yeast or S-04 mutation), would subsequent batches using this mix of fermentation critters be expected to be a stable combination, or would the yeast/bacteria proportion shift in subsequent batches? I imagine one would need a really good microscope to assess this, but maybe flavor/aroma is all that really matters.

the beer was great

I take it that this batch was noticeably better than others with the same recipe, and that's why you even want to pursue this.? If it's basically the same except somewhat more attenuated, it wouldn't seem to be worth the bother.

Happy brewing, @Hoochin'Fool !

 

[Hoochin'Fool]

Just wondering, having no experience with such things:
If this is a "lucky infection" with some bacterium (rather than a wild yeast or S-04 mutation), would subsequent batches using this mix of fermentation critters be expected to be a stable combination, or would the yeast/bacteria proportion shift in subsequent batches? I imagine one would need a really good microscope to assess this, but maybe flavor/aroma is all that really matters.

That's what I'm wondering!

I take it that this batch was noticeably better than others with the same recipe, and that's why you even want to pursue this.? If it's basically the same except somewhat more attenuated, it wouldn't seem to be worth the bother.

I wouldn't say noticeably better, but it was fine, certainly nothing wrong with it. As for reason to want to pursue this... I don't have a solid reason beyond a bit of idle curiosity. Plan is to make a starter Thursday, and if it smells/tastes fairly normal, make the same base recipe on the weekend, but this time tweaked to expect 89% attenuation (so I can target 5.2% abv, not 6.4%)...

 

[mashdar]

I'd expect the culture to converge on something predictable pretty fast if the process was very standardized (same beer, same temperature, etc) and brews were frequent.

If you're brewing different beers, amount of hops, temperatures, gravity, pH, etc will keep changing.

If brews are less frequent, you're battling against different life cycles/viability depending on timing.

 

[sibelman]

I'd expect the culture to converge on something predictable pretty fast

This seems super-reasonable. I suppose S-04 could even resurge and eliminate the imagined newcomer.

 

[mashdar]

This seems super-reasonable. I suppose S-04 could even resurge and eliminate the imagined newcomer.

This is probably the case if brewing every day or two - otherwise historic breweries wouldn't have had relatively pure yeast.

 

[Hoochin'Fool]

Opened (and enjoyed) one of the "trubby" bottles, there was a good quarter inch of sludge at the bottom, which I poured into about a quart of 1030ish wort. What should I be looking for, to determine if this is going to be a worthwhile endeavor?


update: tasted the 2nd "trubby" bottle side-by-side with same recipe that finished normally. The "normal (fg: 1011)" one tastes better, for sure. Probably not going to proceed any further with this mutant/infected yeast.

 

[mashdar]

Do you have a month an an interest in learning to streak agar plates? lol

 

[Hoochin'Fool]

Do you have a month an an interest in learning to streak agar plates? lol

definitely not!