For me it is just a matter of time to use up what I have coated. I figure it's better off cold in the can than finished and coated but I could be totally wrong, too. For some reason I can't get over the idea of shooting frugally like I'm using Portra. I hate wasting film. But handmade emulsions should be shot up and enjoyed. (Actually the Portra should, too.) Once it's gone you get a new excuse to make more.