Help! Is my problem a result of fermenting temps??

[wineshop]

The last 2 batches I've brewed have just come out, well .. not very good. I've been through the whole process in my head and I'm wondering if my problem is my fermenting temps. Both brews were partial mash kits, one from AHB the other from NB. Both were fairly straightforward. I was extremely careful with the instructions (times, boiling temps, hops additions, etc) and I was very careful with cleaning. The way I controlled fermenting temps are with a window unit. It's a small room and I just drop the A/C control and keep the ambient temperature in the room about 2-4 degrees less than the suggested temps. But as the outside temps change, the room temps would change. So it probably bounced +/- 5 to 7 degrees. In both cases the beer (both IPA's) just came out odd tasting and extremely bitter, tasting mostly like alcohol and not so much beer. FYI my SG's were almost spot on. One other thing - this last batch I fermented about 2-3 weeks longer than the instructions said (poor planning on my part due to work). But I read up on the subject here and I didn't think that would be a huge issue. Any advice? I know it may be hard to tell from the info I provided, so please ask if I can give any other details that might help you diagnose my issues. Thanks!

 

[BlueHouseBrewhaus]

Without knowing exactly what the temps were, it's hard to say. What you describe as alcohol flavor sounds like fusel alcohols, which can result from fermenting too warm. Most yeasts want a temperature in the low to mid 60's. Most can tolerate up to 70 but once you get above that you start getting phenols and fusel alcohols. You should have some means of monitoring the temperature in (not just outside) your fermenter. The little stickon "fermometers" sold by most brew shops are reasonably accurate and will give you a better idea of the true temp of your beer. Once you know that, you can start to work on controlling the temps.

 

[dkeller12]

What temp did you set the a/c at?

 

[wineshop]

What temp did you set the a/c at?

I set the temp on the A/C to about 63, which kept the room at about 65-68. The yeast called for 68-72. However, I did not check the actual temperature of the liquid inside the fermenter. I know for a fact one night the temp in the room went up to about 75, but only for a few hours. I don't know if that's long enough to do damage. The stickon temperature thing sounds like a great idea. I'll get one of those.

I'll eventually get a freezer and a temperature controller. But for now I'm trying to make do with what I have.

Thanks!

 

[tooldudetool]

It sounds like high fermentation temps are most likely your problem, assuming you are pitching enough yeast as well (meaning rehydrate dry and make starters for liquid). A plus or minus 7 degree swing is pretty huge, and yeast don't like huge temp swings. I wouldn't use an AC unit to try to control your fermentation temps for several reasons. For one, its gonna be expensive to keep an entire room and all of the objects in it at 65 degrees when all you need is a 6 gallon bucket kept cool. For another, it is a very imprecise way to try to control the temps, as various parts of the room are going to be various temperatures depending on where the AC unit is located and blowing and the thermostats on those window units aren't terribly accurate, they are relying on the air temperature that is passing by the thermostat sensor, which probably isn't close to the temperature inside the fermentation bucket, which is what you want to worry about. As someone mentioned above, get the stick on thermometers if you don't already have them. The cheapest solution is the tub swamp cooler with frozen water bottles option, but the easiest and best way is a dedicated fermentation fridge with temp control. Either way will drastically improve your beer. And keeping your beer in the fermenter for a month isn't a big deal... however with IPA's, fresher is better!

 

[wineshop]

Thanks, Tool. Some great info to consider. The tub swamp cooler combined with a stick on thermometer sounds like a good stop gap plan for now. The dedicated fridge is indeed in the plans, though.

Thanks again!