I recently made my kolsch again using the same yeast ive reused around 6 times. The batch came out tasting like bubblegum.. Was this the yeasts way of telling me it quits?
I could not tell you. I have only used my yeast three times. Was it 6 batches of Kolsch or six batches of the same yeast? I have read that yeast can mutate after several uses. What temps do you ferment at? I hope your beer is at least drinkable. Take care.
Which yeast was that? Some yeasts produce bubblegum flavors...but a good Kolsch yeast cooly fermented should not. If you are not an experienced yeast harvester, I would just bite the bullet and buy some fresh yeast.
There are a few yeasts that are known to make bubblegum, but they haven't made bubblegum for me. Is reusing the yeast 6x the secret to producing the elusive bubblegum aroma?
I would agree. What was your fermentation temperature? How long since you last used this yeast? It will only keep in refrigeration for 8 or 9 months, and by then you'd definitely want to make a yeast starter. If you used a big healthy pitch of reasonably fresh yeast, fermented cool, and it tasted like bubblegum, then yeah, your yeast has grown too tired to repitch and you should buy a new pack.
I won't say your speculation is definitely wrong. But I wouldn't automatically assume this is tired yeast. I've never heard of bubblegum as a symptom of tired yeast. I have had a Bo Pils (made with a large starter pitch made from a new yeast vial (Urquell strain)) inexplicably taste like bubblegum before lagering. It later cleaned up just as inexplicably and was a successful competition beer. FWIW, I had made the same Bo Pils recipe several times before and after, with no bubblegum flavor at all...there was really nothing different about this batch expect for the (temporary) result.
Can't say if it's tired or stressed, but my most recent batch of Kolsch using White Labs yeast and a stir plate starter developed a slight banana flavor (lagered for 6 weeks). I've typically used Wyeast for my kolschs, I wrote it off as being a strain character. It is very slight though, and the beer is (was) very good. How much yeast did you repitch? You might get benana from under pitching.
That's a good point. There are other potential causes, including contamination from wild yeast, etc. Also worthy of note is that esters such as banana and bubblegum should indeed age out over time. Several months of age might diminish or even eliminate a small level of bubblegum, if you can stand to wait a while.
It was probably stressed out yeast. I had that happen and it was the yeast. I have since bought recipe kits from this website, they had a Kolsch ingredient kit. http://theartofbrew.weebly.com
How do you know it was caused by stressed yeast in your case? Are we to assume that your original, stressed yeast was from a bad supplier, but that the store you're pimping in half of your posts sells unstressed yeast?
