Acetaldehyde in kegged beer

[h22lude]

I just kegged an amber ale. It was an extract with steeping grains. I pitched in the low 60s and fermented at 65. A little over a week I raised the temp to 68 then at 2 weeks I dropped it to 34 for 4 days. I made a starter and used an aeration pump.

I tasted a little when I kegged and it tasted appley. Right now it is carbing at 12psi at 41°. I read carbing with sugar helps reduce acetaldehyde. Has anyone had experience with doing this? I have had a few beers turn out appley and it never went anyway. I'm worried that will happen to this batch too.

 

[flars]

HBT Wiki which may give you the information you need to solve the problem or prevent it in the future.
https://www.homebrewtalk.com/wiki/index.php/Green_apples

 

[Denny's Evil Concoctions]

Are you using a temp controlled fermentation chamber?

If so, if the carboys are not raised off the bottom they tend to get cold on the bottom and the yeast tends to settle prematurely. Same thing for carboys sitting on concrete in a cellar or garage.

Also temp controlled freezers can swing in temp quite a bit depending on the cycle time and where the temp probe is placed.

 

[h22lude]

I am using a temp control. I have a freezer on top refrigerator with an eBay controller. I taped the probe to the side of the bucket (about half way up) with a few layers of bubble wrap to insulate it. The bottom of the fridge has two drawers for fruit and vegetables that I kept in so it sits on that. If I took those out the compressor bump gets in the way.

I used a starter, I used aeration, I used temp control...I can't think of why I would get this much acetaldehyde.

 

[TheBrewingBear]

Does it taste sweeter than expected? If so, it may have stalled. Gravity readings would help determine this as well.

 

[h22lude]

No it finished around what I expected. It was a few points higher but not bad. It was extract so I really thought it would finish at 1.020 but it got to 1.017.

Tonight I'm going to check my stc-1000. The temp of that might be off which would explain it.

 

[ArcaneXor]

Did you crash it or ramp it when you cooled it to 34?

 

[h22lude]

Did you crash it or ramp it when you cooled it to 34?

What do you mean ramp it? Ramp it seems like you would be bringing the temp up.

I cold crashed it for a few days. I don't bring it down slowly (if that is what you mean by ramp it). I just put my stc-1000 to 34. It takes a while for the 5 gallons to come down to temp.

 

[BreezyBrew]

I had this once on my second batch and I did everything right that I know of. Never did find out the problem.

 

[h22lude]

Just checked my stc-1000 and it was only .4* off. I was actually hoping it was off by a lot just so I can explain why I have this off flavor right now. As of right now all I can do is wait and see how it tastes in 2 weeks, Hopefully it is just because it is young but it seemed way too strong just for that.

I really can't think of anything that would make it like this. I used a starter which I put in yeast nutrients and used my aeration pump. That was temp controlled. Brew day went great. Off by a few points but nothing bad there. Used distilled water (extract batch). Even put in a little more yeast nutrients into the boil. Cooled with wort chiller and cooled top off water. It was actually too cold so I put it in my fridge with my heater on to bring up temp a little. Aerated with pump and I rocked it right before pitching. Temp controlled through out fermentation. Right amount of healthy yeast, aeration and fermentation temp are the 3 biggest things to worry about and I did all.

The only thing I can think of is this flavor is coming from a piece of equipment. It is just an odd flavor to come from a piece of equipment. Though I will say I did taste the sample I pulled to check gravity using my wine thief and that tasted good. When I kegged, the leftovers in the tubing after racking was when I tasted the appley flavor. Either it is my auto siphon or I just got the bottom of the batch with some yeast in it.

 

[Denny's Evil Concoctions]

It's almost always from incomplete fermentation. Yeast dropping out before they have cleaned up the acetaldehyde.

Are you using a spacer under your carboys?
Check the cycle timing on your controller as well.

 

[EoinMag]

Unless you've filtered or used a lot of cane sugar it'll mature out.

 

[h22lude]

It's almost always from incomplete fermentation. Yeast dropping out before they have cleaned up the acetaldehyde.

Are you using a spacer under your carboys?
Check the cycle timing on your controller as well.

It was a day or two over 2 weeks. With a good starter, healthy yeast, good aeration and temp control, that should have been plenty of time for the yeast with that kind of low OG.

No spacer but isn't sitting on the floor. It sits on top of the two vegetable/fruit drawers.

I have it set to .5*.

 

[Denny's Evil Concoctions]

Try warming the carboy up into the 70's and give it a swirl. Alternatively warm it up and pitch some yeast.

 

[h22lude]

I actually did that. I warmed it up to 68 before I cold crashed. For this one I will just have to wait and see if it goes away.

 

[Denny's Evil Concoctions]

Yes, but did you pitch new yeast? Acetaldehyde must be converted to alcohol by yeast or it will never go away.

 

[h22lude]

Yes, but did you pitch new yeast? Acetaldehyde must be converted to alcohol by yeast or it will never go away.

No I didn't pitch after warming up. Didn't think I had to.

 

[Denny's Evil Concoctions]

Well. If the taste is still there and warming it on its own doesn't help then try what I said above.

 

[InLimbo]

I"m finding this a little late, but what yeast strain did you use to ferment this beer? You said you've had some acetaldehyde in other beers as well. Were these same beers fermented with the same yeast strain? Certain strains are more prone to this off flavor. Your methods and procedures sound spot on. Assuming your sanitation is good, I wouldn't be surprised if it was the yeast.

Personally I wouldn't throw a fresh pitch of yeast into a beer that has already reached terminal gravity. At 1.017 there's nothing left for them to eat. You can't just drop them into your beer and will them to remove the acetaldehyde : )

An additional thought: I've had acetaldehyde in one batch of beer, but it aged out. The fact that yours hasn't aged out in the past leads me to wonder if you're getting an aceto bacteria infection. This can give similiar off tastes (usually refered to as cidery) that will not age out. I'd triple, quadruple check your sanitation.

 

[h22lude]

I do sanitize everything well. I use PBW and OxiClean to clean everything after each brew day. I use Star San to sanitize everything during brew day. I think sometimes I over sanitize which is why I haven't really thought much about an infection.

My procedures seem to be pretty damn good which is why I am having a hard time trying to figure out why this beer and others have had this flavor. An infection may be possible. I might replace some of my plastic pieces to see what that does. When I took a FG reading and tasted the sample it tasted fine but after racking to a keg it had the apple flavor. It could be my auto siphon.

 

[Denny's Evil Concoctions]

IYou can't just drop them into your beer and will them to remove the acetaldehyde : )

Yes you can.