You got me wonderin'... would my HVAC vacuum pump hooked up with a hose to the outlet on the lid of a pressure cooker full of bud in the deep freeze work for freeze drying?
I used to have a high vacuum, high volume vane type vacuum pump that would boil water at room temperature. I used it to dry out soggy balsa core sandwiched between the fiberglass skins of sailboat hulls... I let it slip away when I left the marina industry. I got that pump for $0.15/lb. when my friend ran a junkyard, but they were about $500 new (30 yrs ago).