I'm not sure what ingredients you use in this recipe so am only offering advise on gumpaste I use. I use Nic Lodge's recipe, I wrap it in plastic wrap and then put it in a ziplock bag in the refrigerator. Bring it to room temperature when I am going to use it. If I am just doing a few flowers or a small molded piece I just break off what I need and keep the remainder wrapped and refrigerated. It keeps in the refrigerator for months or he says it can be frozen for up to 6 months. I have never tried freezing it because I use it fast enough that it isn't around longer than a month or two and it keeps that long refrigerated.
http://www.nicholaslodge.com/gumpaste.htm
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