Temp probe fell out, fermenter controller pushed beer temp to 87F overnight.

[Jopher]

My first post, so apologies in advance if I'm doing this wrong.

Backstory: Been brewing for a few years, all-grain for about 2 of them, and usually stick to medium-gravity stuff, ~5-7%. Some friends are big fans of Belgian tripels, so I brewed one with the hope of bottling half for friends. Probably the most ambitious beer I've attempted yet. Brew day and first 5 days of fermentation went beautifully using Wyeast 3787. OG 1.086, only a few points below my target.

Yeast went crazy first few days. I have a temp controller and the beer held beautifully at 68F, ramping up to 71F over 5 days. Took a gravity sample yesterday and was at 1.014. Even the sample tasted good, which never happens, and I start bragging to my friends about how much they're going to love this tripel. (Foreshadowing)

Last night for the first time I *wasn't* obsessively checking on the beer, and so it wasn't until this AM that I noticed I'd knocked the temp probe out of the thermowell when I took my gravity sample, and my controller decided that the beer was actually the temperature of the basement floor. Overnight it pushed it up to 87F. Wyeast gives 3787 a temp range of 64-78.

Swore a lot, cried a little, took another gravity sample and now it's about 1.010, well under my expected FG. I know the answer to the question "Is my beer ruined" is almost always "Probably not, but wait and see." I'm hoping this happened late enough in the process that not too much damage was done. But if someone with more knowledge/experience can describe what kind of mischief my yeasty pals might gotten up to during their excursion to the sauna, maybe it'll help me worry a little less, or at least be a little wiser. And is there anything to do here other than keep calm and carry on? My biggest worry is that additional drop in gravity. Is this beer - which was supposed to be for friends - going to be full of hangover-causing fusels?

 

[VikeMan]

Swore a lot, cried a little, took another gravity sample and now it's about 1.010, well under my expected FG. I know the answer to the question "Is my beer ruined" is almost always "Probably not, but wait and see."

Did you taste the gravity sample? If so, how did it taste?

The "stage" for fusel and ester production is set by conditions pretty early in the fermentation, even though you have to wait longer to know if you had a significant problem, i.e. until most fusels have been converted (or not) to esters.

You say you were 5 days in before the unintended increase, so you might be fine, IMO.

Swore a lot, cried a little, took another gravity sample and now it's about 1.010, well under my expected FG.

My guess is that 1.010 was probably where you were going to end up anyway. I think that, effectively, your unintended temp bump caused a forced fermentation test of sorts, just getting you to 1.010 faster,

 

[khannon]

The assumption that I am making based on reading this is that you were past day 5 of fermentation? If so, while it might make a flavor difference, the impact is going to MUCH less than if it had happened during the first 3 days or so. I don't imagine you should get fusels or at least noticeable amounts that far into fermentation. It might be a little "drier" than you like. If so, feel free to package it and ship it off to me, I'll get rid of it for you.

My go-to tripel starts at 1.084 and ends at 1.010, and it's placed at a few local brew comps, and the kegs seem to empty pretty quickly.

 

[Stand]

Most of the primary fermentation should have finished before you knocked out the probe, so I wouldn't be worried at all regardless of the yeast. That said, if you have read BLAM many of the abbey/trappist breweries allow their beer to free-rise to mid-80s by the end of fermentation.

I ramp the temp up with my trappists to finish them out using WLP530 (which is white labs version of the yeast you used).

I bet you're golden.

 

[IslandLizard]

Yeah, I'm with the others, at 1.014 there isn't much left to do for the yeast except conditioning and finish out the last few points. If anything, the unintended temp rise helped the yeast do that.

Overnight it pushed it up to 87F.

What was 87F? Your beer or the ferm chamber?
Most ale yeast thrives at 90F, you surely didn't kill her!

Yeast went crazy first few days. I have a temp controller and the beer held beautifully at 68F,

You sure the beer itself was at 68F? If it was higher, maybe next time try to aim a little lower.* There's a delay between the chamber's temp and the beer's actual temp. The only way to know is using a separate probe (in a thermowell) inside the fermenter, at or near the center.

* Belgian yeasts can deliver excellent beer at somewhat higher temps without generating lots of fusel alcohols. The higher temps do create more flavor and character, which is all part of Belgian brewing.

Relax, this may well be the best beer you've brewed!

Just try to avoid oxidation during the next week and following steps (packaging). Oxidation is probably more harmful than a short temp overshoot like you had.

 

[Jopher]

Did you taste the gravity sample? If so, how did it taste?

I did, and compared to the previous day I detected distinctive notes of despair and panic. But with a little time and the thoughtful responses here, it's probably really not that different.
Thanks all for your reassurance; seems like I may have dodged a bullet here by timing it as I did.

 

[Jopher]

What was 87F? Your beer or the ferm chamber?
Most ale yeast thrives at 90F, you surely didn't kill her!
You sure the beer itself was at 68F? If it was higher, maybe next time try to aim a little lower.* There's a delay between the chamber's temp and the beer's actual temp. The only way to know is using a separate probe (in a thermowell) inside the fermenter, at or near the center.

I wasn't worried about killing it, more about fusels or other off flavors, but I'm now getting the impression I was probably past the time when those were a risk.
In both cases I'm referring to beer temp, based on sensor in a thermowell. My 'chamber' is just an insulated box in a cool basement, which means I rarely need to worry about cooling; I just heat with a wrap
(I also recently build an iSpindel (DIY floating hydrometer) and it was in the beer; it was logging temps but I wasn't using it for control, b/c it only reports every 15 minutes. It's numbers matched the thermowell numbers, though.)
I realize the irony in employing all this tech and then having it screw with my beer.

Relax, this may well be the best beer you've brewed!

I've learned SO much from this forum. Why I can't seem to incorporate the most-repeated advice here ("relax!") is beyond me.

Thanks again, all. The feedback was educational and comforting.

 

[VikeMan]

I realize the irony in employing all this tech and then having it screw with my beer.

You're not the first one to have a temperature probe get knocked out of place. Some people have even plain forgotten to put probes in thermowells in the first place. Not me, of course.