I bottled a 12 pack of a Bock. I used Cooper's priming drops in order to bottle condition this portion of the batch, 1 drop per bottle. The rest of the beer was put into a Keg and carbinated via CO2. The Keg beer tasted good and had no off flavors. On Sunday I opened one of the bottles. The beer appeared to be over carbinated and had a very strong metallic taste. Does anyone know what may have caused this and what can be done to prevent this in the future? Thanks!
Is this just one bottle or are you having problems with the entire bottled batch?
I can think of a couple of possible problems:
1) Some metallic ions (e.g., nickel) can promote gushing.
2) Oxidation can sometimes produce metallic-tasting notes. That plus some sort of infection (which chewed up some of the sweetness that would have hidden the metallic notes) accounted for the gushing.