... I rigged up a raspberry pi and connected it to a thermwrap to regulate temperatures for my wort. All was working swell until I made a slight tweak in the code, and commented out the section that turns the fermwrap off when it gets too warm ...
The yeast has a temperature range of 64-72°F. It had been brewing for 8 days when I made the change in the code, and then it jumped to 89°F. I think it was like that for 24 hours.
Should I just throw this batch down the drain?
I believe with all homebrewing that there is never a wasted batch, even the worst of the worst is an opportunity to learn something, so don't throw it out yet.
You were lucky it was so late in the fermentation. The yeast won't die at the high temperature, and at this stage you may find you increased attenuation slightly. If a gravity reading indicates fermentation is done, I would cold crash and taste and decide then if you think it is worth saving.
If this had been with a lager yeast you would probably have killed it, any thing above 77°F/25°C will kill off most of your viable lager yeast cells. But, your standard Ale yeasts will survive OK up to about 100°F/37°C.
So wheater pitiching or using the yeast to condition after 8 days in the FV as in your case, with an ale yeast you should be fine.
