Chrones pretty much responded with a lot of what I would say... but here's a quick rundown of my technique with some minor differences:
- Prepping: I spray my dry trim with water immediately before freezing. Still experimenting with how this makes a difference. Seems to me the trichomes/stalks will be coated in a layer of ice right off the bat, making it easier for them to break apart in the ice-water mixture. I also feel that the water slightly reconstitutes the leaf, making it less brittle and therefore less contaminant in the final product. Like Chrones said, if you have the option of freezing fresh uncured trim, do it - don't bother drying it. You will get the best product from "fresh frozen" trim. I don't have access to that, so I use the dry.
- Mixing: I pour some ice water into the bottom of the bucket, then add a few inches of crushed ice. Then a few inches layer of frozen trim, followed by another layer of crushed ice. Add a second layer of trim, then cover it with the rest of my ice. Fill the bucket with ice water, and let rest for 20-30 minutes. Then I mix by hand for 3-5 minutes (I do my mash in a bucket without any bags first, then transfer to bags after mixing) pour it into my first work bag and let it sit for another 20-30 minutes.
- Draining: as I lift the first work bag, I let most of the water drain out... but then I like to pour a couple of gallons of ice water right on top to flush any remaining loose trichomes to the bottom of the bag. I do this instead of doing a second run on the same material. It increases yield, and prevents the decomposition of leaf contaminants you get from letting your wet, stirred trim rest too long.
- Washing: the rest of the draining works pretty much the standard way... working your way down through to the smaller bags, except just like Chrones said, I use a spray bottle filled with ice water to "wash" the trichomes in the bottom of the bag a few times to flush contaminants out before spooning the hash out of the bag.
- Drying/Curing: I let my fresh spooned patties rest on a 25m screen for about 20 minutes, then I transfer to unbleached parchment paper and use the edge of my spoon to break the pattie apart into a powder. I make loosely folded pouches from the parchment paper, which I label with the screen size then rest on paper towels in a dark & dry location (for me, this location is a wooden shelf in a room with a radiator - that dry heat helps it cure). The moisture wicks through the parchment to the paper towels, which I change daily until no more moisture is apparent. In all I let the product cure for about 10 days before sealing it in a mason jar and storing is in a cool, dark place.
I was a farmer for several years (indoor and out) back in the day, but I only started making bubble hash a couple months ago, so I am by no means an expert -- if anyone sees flaws in my process, I'm all ears.