Ok, for what it is worth, 15% moisture is ideal. Good luck in figuring that one out! You would have to weigh the tobacco dry and untreated. Then, weigh it after the moisture has been applied. Don't bother! If the tobacco is just beginning to clump when pinched, it is probably perfect moisture. There has been a lot of good advice here, already. I'll just add that to moisten tobacco, do it indirectly, not directly. For example, if you have an air-tight container, get yourself a spray bottle that emits a fine mist and simply moisten the inside of the lid of your container with tap water or, if your water is high-mineral, I suggest you use distilled water. Do not apply to the tobacco directly. Test your moisture level the next morning with the "pinch & clump test". If it clumps, it is too moist. If it doesn't clump at all when piched tight between your thumb and fore-finger, it is too dry. If it partially or just begins to clump, you got it right-on! That is my humble opinion. And, I will add, dryer is better than wetter!
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