Its fine. My only worry is if it is in a plastic bottle. If not you're totally fine. The harsh taste is caused by metal contaminants probably primarily iron. Some of that iron may have settled to the bottom in that temperature and if you have a dropper and pulled liquid from the bottom that would explain the extra weird taste. I make the purest Iodine on the market woth no harsh taste at http://www.naturehackerproducts.com, go to health remedies and scroll all the way down. Iodine is a mineral so heat will not effect it at all. Worst case scenario if you get it too hot the Iodine will poof out of solution causing a purple cloud! don't ask me how I know ;).