Homebrew Off-Flavor Question

I don't have much confidence in my diagnosis, but a problem that sets in over time like that sounds like oxidation to me. If the ingredients were bad, or something like that, the beer would never taste good. If I were you, I would try to minimize oxidation when you are bottling your beer, and see if that helps.

 

I would guess one of three culprits: 1) extract "twang" from only doing a partial boil; 2) oxidation; or 3) not ideal fermentation practices.

 

Seems like oxidation. Ideally, if you can get a CO2 tank setup, a Cornelius soda keg, and a beer gun or counter pressure filler, you should be set. You should be purging the bottles with some CO2 prior to filling.

If budget is tight, I would at least go to bottling bucket with spigot and bottling wand. The former method ($$$) is the best way to fight off oxidation and protect you're beer that you spend hours brewing and weeks fermenting.

 

Yeah, I mean, to put this in perspective, I think a lot of homebrewers are happy with their results without purging their bottles with CO2 etc. It might be helpful, but it is far from necessary. Your beer should not be experiencing problems this severe just because you aren't purging with CO2. (Also, as an aside, there is nothing wrong with using corn sugar as your priming sugar. You could also use table sugar, which is cheaper, but either way, the priming sugar is not the culprit.)

I don't have any concrete suggestions. You could try brewing a porter - dark beers are less susceptible to oxidation. If the porter holds up better, that's a sign that the problem was oxygen.

 

Maybe bring a bottle or two to your local Home Brew shop for the staff to taste and opine?

 

Yes. Actually this is what I initially suspected. If you are tasting a "yeasty" flavor, it might be yeast. Maybe if you pour carefully enough to keep the yeast sediment out of your glass you'll get rid of that off flavor.

"Yeasty" or "bready" aren't typical descriptors of off flavors from oxidation.

From How to Brew:
Yeasty
The cause of this flavor is pretty easy to understand. If the yeast is unhealthy and begins autolyzing it will release compounds that can only be described as yeasty. Also if the beer is green, too young, and the yeast has not had time to settle out, it will have a yeasty taste. Watch your pouring method too, keep the yeast layer on the bottom of the bottle.

 

Yeah, I mean, the question is what to do with this evidence:

One thing we could do is write this off as an artifact of a small sample size or some kind of psychological phenomenon. But if we take it seriously, then we need a flaw that isn't apparent at first, but that becomes overwhelming within a few weeks, during which the beer is refrigerated. It could be that there is not much yeast in suspension when the beer has been in the freezer for an hour, but there is a lot more yeast in the beer after a few weeks of refrigeration. Since that seems unlikely to me, my initial thought was oxidation, which would dull the beer's hop flavors and leave behind everything else. But maybe something about the freezer time takes yeast out of suspension especially thoroughly.

 

Have someone who is a trained taster give you an evaluation. A local brewery would be a good start, have the Brewer taste it. Find a local Homebrew club, go to a meeting, ask who is the best at evaluating beer, ask for constructive honest feedback.

 

Yes it does fall out at lower temps. In fact many if not most homebrewers practice something called "cold crashing" which involves chilling the finished beer down into the 30's for a few days to a week in order to get the yeast out of suspension thus resulting in a clearer final product. Don't worry, there will still be enough suspended to carbonate, it may take an extra few days though, but you'll see a difference in the clarity.

I might still take it to a homebrew store of find an experienced homebrewer to sample but I think @ssam hit it on the nose. If you haven't read "How to Brew" yet I'd get a copy stat. You won't regret it.