Originally Posted by kegtoe
took a sample off the tap at the bottom. tastd way too sour and the beer was pretty dark. i dumped it down the drain, bleached the bucket twice. this beer was in a tertiary for 12 days. it was fine before i racked it.
I agree with NorCalAngler. I would encourage you to stop fermenting in bottling buckets or at a minimum not to use the spigot unless you are preparing to empty the beer out in its entirety.
All it takes is a drop or two of wort or beer left on that spigot or trapped on the inside in the turning mechanism to catch some lacto. Then the lacto gets in the beer and starts chewing on the residual sugars. Next thing you know you have that.
I would suspect that since you said this was a tertiary fermentation that you have had this beer sitting around fermenting for at least a few weeks. You probably got the lacto in the beer for a while and it took over the batch during those 12 days it sat in silence.