Fermenting Temp Questions

Hi All,

Just a couple quick (hopefully easy) questions:

1. I've got temperature strips on two plastic fermenters (@ the mid-level on the side of the bucket), and on my glass carboy. Does the temperature shown (74 degrees on all of them) indicate the ambient temperature of the room, or the temperature coming off the brew? The strips say 74 degrees, but it's more like 70-72 here in the apartment.

2. How do I know what temperature to keep the wort at during fermentation? The yeast I used gave a pretty big range (65 - 75 F). I get the concept of a swamp cooler, and have the parts to make it (i.e. T-shirts, container, frozen bottles), but is it really necessary for a non-lager wort if my apartment is consistently 70-72 degrees? At what temps do nasty tastes start occurring for Ale yeast (brewing 2 Scotch Ales, 1 Pale Ale).

Thanks!

1. a pretty good indicator of what's happening inside the fermenter. many people have tested these and most come up with a difference of 1 degree either way. so, not ambient.

2. it all depends on what flavors you desire from the yeast. higher temps will give you more ester production (frutiness) and fusel alcohols. IMHO, it's best to keep most ales fermenting around 66-68 if possible to limit off flavors. but you will likely be just fine.

you can count on the beer fermenting 4-8 degrees higher than the ambient temp.

For most ales, as long as you hold down the temp close to 66-68F for the first few days (until the most active fermentation is done), after that, a 70F room will be a-ok.

I got some fusel alcohols (solventy) from WLP002 at ~74F, but hey, every ferment is different.

I try to aim for the low end of yeasts suggested range with the ambient temp. That way, when the fermentation generates its own heat, it will still be in the range it needs to be.

For example if the yeast says 65 - 75, I would go for 65 for the temp outside the fermentor because the fermentation may cause the wort/beer to go up to 70, but that is still fine.

I fermented my second batch, a dunkelweizen, at about 72. It tasted very banana-y at first but is starting to mellow and tastes awesome.

I'm having my own trouble with cooling now that it's even warmer, though.

It really depends on the yeast, I have some beers that like to ferment 70-75 and give no off taste at all. Once you start to get above 75 things can really start to gain off flavors. There are others that ferment in the low to mid 60s (like a true ale). It all just takes time and understanding of your specific brew with that yeast, sometimes a high temp will screw up the taste but after a little time in the bottle it becomes a great beer. Stay away from those 80 F fermentation's tho, that can really screw up a beer.

+1
depends on the yeast
follow mfg recommendations.
--and fermentation activity raises temp inside your vessel above ambient (as disclosed by your stick-on strip) by 4-8 degrees, as stated by Android.

you're probably fine with these, but you're also correct to pay attention to your temps!
good luck!

+1

After bad sanitation practices, improper fermentation temperature is what is going to mess up more beers. A good plan of action is to try to pitch at the low end of the yeasts' range. A lot of activity that is temperature dependent goes on in the first 24 hours. Also, give the yeast plenty of time to clean up after themselves. If you can, 3-4 weeks in the primary will get you good results.