I recently had a metallic taste in my mouth for several days, it was very bitter at the back of my mouth. Some investigation on google led me to chat groups which discuss people having this problem after consuming pine nuts, which I had for the first time. This bad taste lasts anywhere from 2 days to a month. It was traced to Sams Club, Trader Joe’s and others brought in from China. Mine lasted 5 days. Since there are many raw fooders and vegans who use pignolias a lot in cheeses and pie crusts, etc. I thought I should pass it along to this group, albeit it may not be relevant to this person if it goes away for the rest of the day.