Off flavors in homebrew

[waynethetrain]

I made a partial mash amber ale a few months back (intended to be like a Fat Tire) and it's taken on an off, fairly intense apple cider type flavor. I've gotten hints of this flavor in other beers I've brewed but this one in particular.

What might cause this flavor? I've heard if the fermentation gets too warm it can impart more fruity flavors, is this likely my problem?

 

[rocketman768]

If it tastes like apples, it's probably acetaldehyde. Acetaldehyde can be made by oxygenating the finished beer, not aging for long enough, or by a couple of types of bacteria.

So, what temps are you fermenting at, are you mishandling the beer, and how long are you leaving the beer in primary and secondary?

 

[waynethetrain]

Thanks for your reply!

I fermented between 68 and 72, but truth be told I don't have an extremely temp controlled environment. Doors open and close and the temp fluctuates a little bit.

Primary was 6 days and secondary about a week. I've gotten pretty good and cooling the beer before disturbing it in any way. Is that generally how finished beer oxidizes? Are there other things that can cause it to oxidize?

As far as foreign bacteria, I'm fairly militant about sanitizing, but I guess there is always a chance for contamination.

The one thing I did do differently with this batch was I attempted to filter to the beer, between primary and secondary fermentation. Basically, on the way into the carboy I ran it through a sanitized strainer. Not sure what I was thinking

 

[rocketman768]

For temperature control, you might consider a "swamp cooler" which is a plastic storage container filled with water and frozen bottles of ice that you swap out each day. You put the primary in this and it will maintain 60-70 depending on how many frozen bottles you keep.

However, it looks like you aren't letting your beer sit for nearly long enough. Yeast metabolize acetaldehyde into ethanol if you give them enough time. Generally, I leave my beer in primary for a month, then straight to the bottling, then leave alone for another 3 weeks or so.

 

[waynethetrain]

Interesting, thanks for the insight. I will definitely try that. From other reading I've done, I thought I should be getting the beer out of the fermenter and into the secondary as soon as fermentation is complete to prevent the dead yeast from giving bad flavors. Should I not worry about this and just leave it in the primary?

I will be making a swamp cooler for my next batch, thanks!

 

[rocketman768]

Interesting, thanks for the insight. I will definitely try that. From other reading I've done, I thought I should be getting the beer out of the fermenter and into the secondary as soon as fermentation is complete to prevent the dead yeast from giving bad flavors. Should I not worry about this and just leave it in the primary?

I will be making a swamp cooler for my next batch, thanks!

Yeast will eventually die and rupture, giving some nasty putrid off-flavors, but that would take more than a couple of months, or excessively high temperatures.

Hope your next batch is good!

 

[ScottD13]

If its apple cider and not green apple then I would say it's more likely an infection. To me the aroma of green apples is way different then cider and very easy to distinguish. It's very difficult to diagnose a problem without a proper sensory analysis because what you think you smell may be perceived differently by others.

Symptom: It smells like vinegar.
Cause 1: Bacteria In this case, it probably is. Aceto bacteria (vinegar producing) and Lacto bacteria (lactic acid producing) are common contaminates in breweries. Sometimes the infection will produce sweet smells like malt vinegar, other times they will produce cidery smells. It will depend on which bug is living in your wort. Aceto bacteria often produce ropy strands of jelly which can be a good visual indicator, as can excessive cloudiness, after several weeks in the fermentor (although some cloudiness is not unusual, especially in all-grain beers).
Cure: If you don't like the taste, then pour it out. Lactic infections are desired in some beer styles.

Acetaldehyde
A flavor of green apples or freshly cut pumpkin; it is an intermediate compound in the formation of alcohol. Some yeast strains produce more than others, but generally it's presence indicates that the beer is too young and needs more time to condition.

You've said you had it before so I'm wondering if it's getting progressively worse with each batch? If so that could be more evidence of an infection. I've had infections in the past and had to toss all my plastics..hoses, paddles, bucktes, etc, to get rid of it. What are you using to clean? PWB, oxyclean?

Now that being said it's always hard to diagnose a problem without tasting the beer...feel free to mail me one ..but filtering it through a strainer could introduce all sorts of things especially o2. But I believe o2 issues take a fair amount of time to show up, so I doubt it. I wonder if the introduction of o2 restarted the ferment and since it had for the most part been completed and there were few resources remaining you may have developed acetaldehyde due to an incomplete second fermentation…..hhhhmmmmmmm

However..one thing we’re overlooking is the yeast. This could be a overly developed ester or off flavor due to temp control. What strain did you use? How much did you pitch? I’ve primared for a week and secondaryed for a week with no issues but some yeast complete their lifecycles faster than others.

Can you offer more info?

Check out How to Brew.com for some quick info on off flavors and aromas.

 

[waynethetrain]

Thanks for all this info! I think maybe I need to make another batch of this brew and this time allow more time for fermentation, skip the secondary, skip the filtering and try to maintain a consistent temp.

The more I read, the more I think I have an infection. The carboy and tubing aren't always easiest to clean. The primary fermenting bucket is alot easier. If the equipment is the problem, do I really need to chuck it? Is there any amount of cleaning that could fix this?

FYI
I use a Straight A and Star San for my cleaning/sanitizing. The yeast was a new Wyeast Activator, I forget which one. I can look it up in my notes if you like. I do all my shopping at Stomp Them Grapes in Denver and they have been helping a lot.

 

[TipsyDragon]

it can be caused by to much cane or corn sugar in the fermentation.

 

[LarryC]

I'm a noob and admittedly am still trying to figure out my own off flavors. However, in one of the early replies it was mentioned that oxygenating the beer could cause this. When you said you rack to secondary and go through a strainer you would be oxygenating your beer a lot I would think.