Don't know where I got the idea, but for my commercial electric glue pot I put the pearls and water in a cleaned vegetable can, and put that can in the inner copper container of the glue pot. Some water around the vegetable can transfers heat to the pearls and water. When finished, I pull out the vegetable can and let it cool, pour out the water, then cover the remaining hide glue and vegetable can with a plastic bag and store in the fridge till the next time I need hot hide glue. if the refrigerated hide glue grows a bit of mold, when the hide is glue is heated I skim off the mold and continue. If excessive mold I toss the contents and can and begin with a new clean can. Don't often use hide glue, but haven't had any failures after heating it this way.