Fusels and my yeast...

So I recently brewed two beers with the same yeast, an ESB and a Robust Porter. The yeast I used was WLP037 Yorkshire Square. I got this yeast from another local brewer after it was harvested from something he'd done (I believe a cider).

Upon receiving the yeast from my buddy I grew up a 1L starter on my stirplate for about 30 hours and harvested it down into a a few vials. Then for each beer I grew another 1L starter on my stirplate for about 24 hours, cold crashed, decanted, then pitched the yeast.

The ESB was pretty was well temp controlled, I had the ambient between 64-66F for about the first week since we had nice, cool temps. The fermenter was sitting in a tub of water to just stop rapid temp fluctuations.

The Porter was temp controlled well for about the first 48 hours, though it was higher than the ESB, more upper 70's as it was a lot warmer at this point. After that I was going on vacation, so I had no choice but to let it sit. I know that room got up into the high 70's while I was gone, but I was hoping that with the bulk of fermentation over I should be OK.

So I entered both of these beers into a competition this past weekend, and though I got no hot alcohol flavours when I tasted the ESB last Thursday and just a little on the Porter, they both now have much stronger hotness and I got dinged for it at the comp. So the Porter I understand, but the ESB came out of nowhere with this!

First thing that's weird is that this was nonexistant in the ESB before and now is very noticeable (I don't want to finish a glass even), second is that I would get an fusels with a reasonably well controlled fermentation.

I'm starting to question the yeast's health, but I can't find any definitive info that would lead me to believe that poor yeast health would cause this alone. Anyone have any ideas at what could be wrong? I'm going to let the ESB sit a while and may also clear it with some gelatin, since a few days at 33F didn't seem to clear it all the way.

How many generations was it used as a cider yeast? It's possible that the yeast adapted for cider environments which made it less than optimum for fermenting beer. Cider does tend to have a hot alcohol flavor when young that needs to age out.

Not sure on that, I'll have to ask him. The other thing I was thinking about is pitching temps. I bring it down as far as I can manage, usually shoot for at least 75F, before pitching. I was reading a few other thread and seeing that higher pitching temps can cause fusel production as well...

yeah I'd try to pitch much cooler like low to mid 60's. With most ale yeasts if you start them 70 or above they will make some harsh alcohols. The first 24 hours is the most crucial time period for keeping the harsh alcohols at bay.

Try recirculation ice water thru your chiller with a cheap fountain pump.

The cider pitch was straight from the vial. I suppose that it could have adapted. the porter that I did with 037 got dinged as well for hot alcohols, but I fermented it too warm so I knew it was coming.

Do you know the temp of the beer inside? Assuming that a beer will sit at 64-66 when that's the ambient temp, even with a water bath is a bit much. I'll bet your temps creeped up over 70 or so for a bit. Do you pitch warmer, or do you let your wort get to 64 before you pitch? If you pitched warmer, the yeast could have rocketed off and kept that beer higher than you expected.

As for not noticing the fusels, it is possible that your nose was thrown off by something else. Maybe the hops were more dominant when it was young, and as they fade, they're making more of a platform for the fusels to shine through.

Yeah, pitching is more mid-70's. Can't really get down further with the current set up. My new set up will likely include a plate chiller, but I could in the interim get a pond pump and recirc some ice water after initially dropping the temp.

Sounds like my problem more revolves around the temp those first hours of the fermentation, so maybe I'll assume the yeast still viable and try again when I have the new gear in place.