I use cellulose. Got it off the web from a store selling craft glue to kindergarten and day care. I generally leave it in the fridge; but I not infrequently forget to put it back. In fact, good thing you reminded me, cause it's here on my desk now left over from last weekend, and I keep meaning to put it back. It sits out for a week or two no prob. Specially when I roll in the garage. I dunno why I always forget it there. Never had mold but once; and I'm pretty sure that's back when I was using that nasty pectin. Mix just the amount that perches on the end of a palette knife with prolly a teaspoon of water in a tiny tupperware pill cup which prolly holds a tablespoon. That much can last thru a double batch of cigars. ... and, no, I don't use distilled water, cause I am not gonna get all anal retentive about three molecules of chlorine invading my ideal world beneath the cap.
It does not mold; but it does get thicker over time. Starts syrup; three weeks later it's paste.