Does metallic only come from rust or can it be from yeast? I have a keg that has a bit of a penny taste. Not the faucet as I swapped kegs. Yeast was 4th gen Rustic/3726.
Could be water related?
Could be the keg. I had a brand new keg that gave off a bloody lip flavor. I cleaned and repasivated using double strength starsan.
I find it can come from oxidation.