I use bubble bags to make hash.....In my own experience (and anyone feel free to add thier 2 cents) I find that fresh frozen trim makes better hash than dry frozen trim. The thing we are trying to do is agitate the mix enuff to knock off and collect the trichomes, while at the same time not pulverizing the vegative matter too much. Dry trim breaks up into tiny particulate much easier than wet trim, and so adds more contaminant to the hash. Mixing methods come into play here. Worst is the paint mixer attachment on a drill, with a cake mixer right behind it, both will pulverize the mix quite a bit, and the smaller stuff will find its way into yer hash. The absolute purists will stir by hand with a wooden spoon (good workout) which introduces the least amount of contaminant. A Bubblenow machine is the cat's meow; I used to use a drill and paint mixer, with the machine it almost seems like cheating. It makes better hash, in less time, with less work. Mixing times affect quality. Short mixing makes less contaminat and better hash, but a lower yield. I'm settling on a 6 minute mix for the good hash, then a 12-15 min mix to get the rest out of the mash. Some do a 3 min mix for super melty stuff. Hope all of this helps some.