I have a Belgian ale I neglected in my garage. It has been in primary for about a month and a half and the temperatures have ranged from 70 F to 90 F. I plan to bottle tonight and see what comes of this one. Has the beer been on the dead yeast too long and been through too big of temperature swings to be salvageable?
What does it taste like? I would let my taste buds be my guide. If the taste were decent, I'd go ahead and bottle. BTW, there are likely plenty of live yeast, but it wouldn't hurt to add a bit more yeast at bottling as insurance; any type of yeast would do.
Vacax is probably right. Granted, those aren't ideal, but there's a chance that it's still OK. What does it taste like? What does it smell like? What does it look like (a big pellicle is probably a bad sign - or maybe a good one, who knows). Take a sample and taste it (just not at 90 degrees... yuck). If it tastes OK, keep going and bottle it or keg it. However, I'd probably add some more yeast at the bottling process - because at 90 degrees the yeast could have died.
I would concur, if it tastes good, bottle it. Use more yeast either way if you bottle it. Obviously don't do that again. Beer-o-cide is a crime around here.
Yeast autolysis is seemingly a homebrew fallacy. I've had beers sit on yeast in warm temps for 4+ months at a time that had no off flavors at all and have heard guys, including professional brewers, had beer sit for upwards of a year with no ill effects. Pay it no mind, should be fine.
Give `er a slight shake to resuspend some yeast. Taste it and see if it tastes good enough to bottle. You'll have a pretty good idea after a month and a half in primary. Rack to bottling bucket and bottle if you think it's good.
