"That website states that a metallic taste in the mouth is acidic and that if you balance the ph in your mouth it will go away."
I found my teeth getting sensitive when I was drinking the lemonade - maybe if you put 1 tsp of baking soda in some water and swoosh it around in your mouth, it will change the PH of your mouth? (but the metallic burps are coming from your stomach? I wonder why you're burping so much? Die off from parasite maybe? Do you normally burp alot?)