[stavesacre]

I just caught my batch tipping towards the mid 80's today, is that the end of things or does it still have a chance if I can get it to cool off a bit?

[majorvices]

You should be fine with that yeast, especially if you started off cool. I'd just leave it.

[GrainSpiller]

If you started off and remained within the 64F - 78F range during most of the fermentation phase, you're most likely to be safe.  For best results, my best advice to you would be to transfer the batch to another area where it is between 70 - 75F.  Be careful that immediate temperature changes from the mid 80's to lower than the (70-75F) range will likely shock the yeast, resulting in slower fermentation.  Yeast cells are not immune to immediate temperature changes more than +- 10F, which can cause them to stall out for some time.  Higher temperatures (the lower to mid 80's) can lead the yeast to producing off-flavors and speeding up the fermentation to the point where the yeast will starve out, leading to incomplete fermentation.  This will probably give you a final gravity result that is not what should be expected.  The yeast need to ferment in an environment most suitable for stability.  If you're unable to find an area, you might be able to run it all the way through, but you might come across some unexpected off-flavors on the way as well.  For the most part, if your temperature range was between 65F - 75F most of the fermentation phase, I wouldn't worry too much about it.  As for conditioning (secondary fermentation) the beer, 64F-68F is a good temperature range.   

[gordonstrong]

I think you're going to have to wait and see.  You didn't say where in the fermentation process you are.  If you're at the end, you might be OK.  If you're at the start, well I hope you have a lot of ibuprofin around.

That yeast doesn't take well to cooling during fermentation.  Any time I've tried it, it's stopped dead in its tracks.

Westvleteren ferments that yeast on the warm side, but not that warm.

I think you're going to have to wait and taste it when it's done.  Even then, you might need to condition it for awhile.  The character of Belgian beer can change significantly after it has conditioned.

[stavesacre]

I guess I should fess up to what I did, probably a fairly big no, no but impatience got the best of me.

I had a Patersbier kit from Northernbrewer that ended up taking a strong green apple flavor. I let it come to room temp and sit for a few weeks with no change. So I transferred it to a new keg, put in about a pound of candi sugar and pitched a new batch of 3787. After two days of slow action I checked the temp at mid 80's.

I'm sure I've brought it too low now to do anything but kick myself. Just pulled it out of my "cool" corner and it was around 65.

[stavesacre]

I think it is going to turn out ok! The beer cooled off a bit too much but it is bubbling away at 70 to 72 now. Smells nice!

[majorvices]

Westvleteren ferments that yeast on the warm side, but not that warm.

According to BLAM they let it raise to the mid 80s. Agree that trying to reign the yeast in can crash it, though. Also agree normally trying to keep the temp from raising to quickly, but glad to hear the beer looks to have turned out for the OP.