Infection?

I went to sample the furlough beer. It tasted ok, but noticed a little ester in there. Is it just green beer taste that will clear up in a few days? Maybe. But I think not. I think it will get steadily worse over the coming weeks.

All my beers for a while now are too estery/cidery. What's happening? Why? One key thing I noticed is that it gets worse the older it gets. This led me to do some thinking and I'm now guessing that the issue is an infection. Some type of acetobacter I'm guessing. They work slowly which is why as the days/weeks go by the beer get worse. I wonder if I were to add oxygen to the beer after a few weeks, would it turn into vinegar? There are a couple of ways we can test this.

1. I plan to make a small batch of beer in the kitchen on Saturday. Nothing fancy. Just some DME, water, and a little hops. Once the wort is cooled I will put it two separate 1 liter water bottles. One of these water bottles will not have any of my gear touch it. From the pot to the bottle. Shake it up to add some O2 the old fashion way, add yeast, and done. I'll use ballons with little holes poked in them as air locks. Then, add wort to another 1 liter bottle but use the funnel, O2 stone, and thief (to check gravity). Basically, all the plasticy things I normally use (except the racking cane). Then I put these in the chest freezer for a couple of weeks and sample.

2. The furlough beer will be given O2 after another week and we can see if starts to become vinegar. Of course if the furlough beer is amazing I'll drink it and not experiment with it. I check it again in a week.

My guess is the O2 stone is the culprit. I jam it in the fermenter every time and I have never completely taken it apart to clean it. All it ever gets is a rinse after use and a boil before use. The boil is only the top 3 inches as well. I'm looking to sanitize just the O2 stone itself. I've never put effort into the tubing.

If this test shows that there is an infection the plastic stuff that touches the beer after it has been cooled must be replaced.