Heating Gum Crystals: The next day, I stirred up the gum mixture—which had begun to look like heavy cream—and found that the crystals could use some more dissolving and thickening, so I sped up the process by making a double boiler. I also added some more gum crystals, which were mostly powdered already. I did not allow the gum mixture to boil, but heated it gently for about 30 minutes until it was the proper consistency, mashing the softened crystals with a spoon as I went.