You find that in all soft drinks. It has to do with the water that the bottler used, which is usually just local tap water. In fact, there are certain areas where I can't drink the sodas because the water has so much sulfur in it. I can't remember where. Possibly down in your neck of the woods in SC. I know it was somewhere around here (I'm in NC), and I'm pretty sure it was to the south, and I was thinking GA, but it could easily be SC. Are you near the coast?