So a quick story to (hopefully) benefit all.
I submitted a few beers to a comp in NYC (Homebrew Alley), one of them being an IPA I made in mid-Dec that I thought was great (judging was mid february). This beer actually came in 2nd @ a local non-sanctioned hedonistic comp in late january.
17.5 from the judges @ homebrew alley. The main thing they cited was acetaldehyde.
WTF? Then I had the last bottle I had at a club meeting in late february. Lifeless. No hops. Awful. One guy said acetaldehyde. ACETALDEHYDE!!? Green apples? How could that be possible? I pitch a ton of yeast, manage it well, etc. PLUS the beer WAS great at one point.
So I was going through my process (typing it out actually) and realized the following. Since I have been kegging, I will typically keg, then bottle with the blich beer gun, so I can free up my serving fridge which also doubles as my ferm chamber. It hit me. I love to 'quick carb'. I don't always CO2-purge when I rack to my keg. So I am shaking up my keg like a polaroid picture with oxygen in there, and diffusing both CO2 and O2 into my beer. As a long-term storer in bottles, this is a major problem.
But wait, why green apples? Why acetaldehyde? One thing I have been very diligent about in my last 20 or so brews is yeast. For the last few years. proper management, starters, pitch rate, manipulate temps well. Acetaldehyde is usually a result of improper yeast management.
Oh wait. Or oxidation....oxidation REVERSES a lot of the reactions that happen during fermentation. "intermediate" compounds that are formed during fermentation AND TYPICALLY REABSORBED rear their ugly heads as a result of oxidation (like acetaldehyde).
Lesson learned (hopefully). I need to drink the $#@!T out of my beers now so they don't have the chance to age and get worse. I have noticed this in most of the beers come to think of it.
I just carbed my 80/- and its excellent. But I didn't CO2-purge. I have heard that you can precipitate out oxygen by adding either additional campden tabs or vitamin C to the keg. I might try this, as I was planning on submitting this AWSEOME 80/- to NHC. Anyone have experience with adding a campden tab (or five) to a kegged beer to reduce oxidation? Or I might just rebrew it.