Why are my coffees tasting metallic? I use long life milk decided to make coffee using my coffee machine… I have not used it for a while. I used some Harris coffee which was new, frothed up the milk and after making my coffee it tasted metallic, not nice! At first I thought okay not used to that coffee before so went back to my old coffee, froth up more milk… Wow yuk! It tasted like metallic again. Does anyone know what I am doing wrong?