WLP029 gone bad

[ba-brewer]

So this is the second time I have had my WLP029 go bad. Last time it had a fairly strong clove flavor and aroma. This time I got banana and clove. Both time they went bad on the 5th repitch of the yeast, previous uses came out clean. First time the temp was 66F and this time I was bit lower at 64F. Both times the yeast started slow, needing about 24 hours or more to really get going where normally they will be cranking in 12hr. Seems to be staying in suspension longer too. One other thing in common was the yeast had sat for about a month in the fridge between the last good use and the one that went bad.

First time I thought maybe I had cross contaminated with a Belgian yeast, but this time I have not used any Belgian yeasts recently. Guess it could be a wild yeast but it sort of funny it only pops up with WLP029 and not other yeasts I repitch.

I did some searching and it seems others have gotten banana and/or clove from wlp029 but it was unclear if these happened on first pitch or on a repitch. Anyone else get WLP029 to shift with a number of repitche?
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[SoCal-Doug]

I've repitched it a few times with good success but i don't remember going five iterations. I use it only for my Kolsch. Can't say I've ever noticed banana (i like some in a wheat, but yuck in a kolsch).

Couple things to remember about 029. It is a mutt, it's not a "pure" kolsch yeast strain. It does however have a little of the kolsch "funk" (i think its more like a Goffel than a cleaner Riesdorf, but definitely not as good as either that those use)

With some whirlfloc in the boil and gelatin at kegging time, its fairly clear after a few weeks. Give it a few weeks more and it really brightens.

 

[ba-brewer]

Thanks for the info @SoCal-Doug

I normally have good luck with wlp029, starts off fast and drops pretty well by day 7 or 8. I do use whirfloc and sometimes gelatin but even without gelatin it normally clears reasonable well with some time. After getting a whiff of the warm gelatin I use it less often now.

I was wondering if it was actually a blend of yeast and over time the mix get out of balance. It is possible something wild got in there and it just took time for it to be the dominate yeast. The flavors seem pretty clean, just not ones I wanted, really don't notice any funk.

The time before it was a hoppy blonde which could of passed for a saison. This time it was a cream ale, sort of tastes a bit like Belgian blonde. I almost dumped this batch but I will let it carb up and see how it drinks first.

I saved the yeast cake and may try a small batch as an experiment to see if it will go back clean if fermented a bit warmer, but don't have too much hope of that happening.

 

[SoCal-Doug]

I love a good authentic Kolsch but my hunch is because there are only something like 18 licensed real Kolsch breweries in cologne, it's hard for companies like white labs to get a hold of yeast. It's also not as popular in the states or with homebrewers, like other styles. We can only come close.

 

[dmtaylor]

You've got contamination. Fermenting in plastic??

 

[TurnipGreen]

I’ve re-pitched 029 for three and four generations and never had a banana or clove flavor. I have a third generation going right now. I always wondered how many generations you could go before a yeast starts changing. I sound like you answered that for 029.

I’ll pull a sample when it’s done to see it there’s any of those flavors.

 

[Northern_Brewer]

I was wondering if it was actually a blend of yeast and over time the mix get out of balance. It is possible something wild got in there and it just took time for it to be the dominate yeast.

Well - to test this you really need to streak to single colonies - ideally both the 6-gen yeast and a sample straight from the sachet - and then brew some small test brews from the single colonies.

Clove suggests a POF+ contaminant of some kind, whereas eg petite mutants tend to go more in a solventy/cheesey direction, so I'd work on the assumption it's contamination rather than mutation.

 

[ba-brewer]

Figured I should update this thread. I found a lab to do some test on my yeast slurry and it turns out I some how got a diastaticus contamination.

The only known diastaticus yeast I have used was 3711 and that was well over a year ago so I might have that still lingering about but I sort of doubt it. I have gone thru multiple sets of plastic transfer tubing and racking canes since then and I also changed from plastic to stainless fermenters after the first time this happened.

I was worried I might have contaminated the beer with my sour dough culture. I fermented some wort with the culture and the aroma seemed similar so I had that yeast tested too. Bad news or good news was that came back negative for diastaticus yeast.

Threw out my transfer tubing and racking cane and gave my fermentors a good cleaning. Hopefully that is enough but I will just have to wait and see if it shows up again.

 

[dmtaylor]

Threw out my transfer tubing and racking cane and gave my fermentors a good cleaning. Hopefully that is enough but I will just have to wait and see if it shows up again.

Sounds right. Must have been the tubing or cane.