Over attenuation

[philjohnwilliams]

My last few batches of beer have attenuated more than expected, mostly finishing in the 1.002 - 1.004 range when the calculator from hopville has estimated the Fg to be in the 1.010 to 1.012 range. My last brew finished at 1.001, and for the first time I have noticed a slight sour taste to the beer. I assume I am dealing with some kind of infection, is it possible that I have had this infection for the past few batches and only now had it established itself enough to affect the taste of my beer? I have been using US-05 and S-04 and I brew extract.

 

[beerkrump]

You may have a wild yeast present. In low enough concentrations, it may be just a lack of body and malt character. As it gets more established, the flavor can get sour. I'd do a 30 minute, hot bleach/vinegar solution (look up what the concentrations) soak on everything that touches the beer post boil.