boozy/acetone off flavor?

[zodiak3000]

ive been getting this "hot" boozy acetone flavor/aroma in the past few beers. i havent been able to get my wort chiller too cool past 75. i usually pitch at 75ish, then crank it to 64 in the chest freezer for fermentation right away. fermentation stays at 64. using wlp001. could this be the reason im getting this flavor? what bothers me is this flavor isnt present until about half of the keg is gone (approx. 3 weeks). the first several pints taste fine, then this flavor pops up out of nowhere. any advice or thoughts?

 

[QuercusMax]

Infection in the keg, maybe?

 

[zodiak3000]

Infection in the keg, maybe?

it has happened the past 2 batches, 2 different kegs. not sour at all, more like hot rocket fuel...

 

[izraehl]

When's the last time you calibrated your temp controller? I use an STC-1000 and the calibration drifts occasionally. Fusels are a sign that you're fermenting too warm.

 

[zodiak3000]

When's the last time you calibrated your temp controller? I use an STC-1000 and the calibration drifts occasionally. Fusels are a sign that you're fermenting too warm.

i have the johnson A419, no idea how to calibrate. i have the probe taped to the side of the carboy in chest freezer.

 

[izraehl]

That could very well be your problem then. Temperature controllers are rarely accurate out of the box. Also, make sure when you tape it to the side of your fermenter that you insulate it somehow (like with bubble wrap) so that you're DEFINITELY getting the fermenter temp and not the ambient within-the-freezer temp. The fermenter should be 4-5+ degrees warmer than the ambient because fermentation releases heat.

 

[zodiak3000]

That could very well be your problem then. Temperature controllers are rarely accurate out of the box. Also, make sure when you tape it to the side of your fermenter that you insulate it somehow (like with bubble wrap) so that you're DEFINITELY getting the fermenter temp and not the ambient within-the-freezer temp. The fermenter should be 4-5+ degrees warmer than the ambient because fermentation releases heat.

what about the pitching at 75 and dropping to ferment at 64? im suspecting this is the problem, could be the temp control as well though. should i try putting it in the chest freezer and getting to 64, then pitch the yeast?

 

[izraehl]

I suppose that could be an issue but I'm not sold on it. Not unless it takes a long time to finally cool your wort down to temp.

However, I'm a believer that you should be pitching once your wort is at fermentation temp. If you use liquid yeast, you should have that around the same temp as you pitch.

 

[Ravenshead]

If you do some more reading you'll find that most of the better brewers like to pitch a little low and let the wort rise to temp rather than the other way around. I'm guessing that's your problem.

 

[jakenbacon]

what about the pitching at 75 and dropping to ferment at 64? im suspecting this is the problem, could be the temp control as well though. should i try putting it in the chest freezer and getting to 64, then pitch the yeast?

To answer your question man, No, I don't think the fact that you are pitching at 75 and dropping to 64 using a chest freezer is your issue. If it is at the half keg point, could it be over-carbonation somehow? That could give a beer a nasty bite....?

 

[KepowOb]

If you want to test whether or not the pitching at 75 is the issue, couldn't you transfer to your primary and stick it in your ferm chamber, wait till it hits 64, and then pitch and see how that batch turns out?