There’s a decent amount of info on freeze drying but it seems to be inconsistent.
I know there are people on here who freeze dry flower to collect the terps (not sure if it’s frozen in those cases), implying the terps are boiling off. But I know people who make hash that use freeze dryers because they preserve terpenes better than anything else.
My hypothesis is that the cold temperatures cause the trichomes to be so stiff/viscous the terpenes can’t boil out (hash) and when people freeze dry flower, they aren’t actually freezing it.
I’m also curious if this can be used for some higher boiling solvents (let’s say ethanol or heptane) where it is 1:1 to 3:1 solvent:resin. If its concentrated enough it may actually freeze and then solvent can be boiled off.
I’m assuming this depends highly on the conditions you run but am confused by much of the information out there. Anyone have specific info they are willing to discuss.
The people using freeze dryers for hash are probably comparing that to using an oven. Those people are only trying to remove water, which, when frozen, can be sublimated off while the trichome heads stay intact. That’s what makes the freeze dryer “better” at preserving terpenes. The people using freeze dryers to collect terpenes from their flower aren’t doing that because it’s the best way to remove terpenes, but because it’s the best way to remove water. Once the water is removed, then the product will yield higher amounts because the water isn’t stealing some of the solvent’s capacity during extraction. The terpenes collected are just an added bonus.
I like your hypothesis. You might be onto something, but I don’t think it can be applied to solvents like ethanol or heptane because they dissolve the trichome heads. So, they wouldn’t be able to freeze and act as a barrier like you were thinking.
Sorry to be a debbie downer. Hope it helps!
I see. I was thinking as a way to remove residual solvent like you would w/ a vac oven but instead you freeze the resin/solvent mixture then sublimate/boil solvent away.
The appeal of freeze drying is that the homogenous, then you freeze it and can boil solvent once the mixture is frozen, allowing for solvent removal via vacuum. Likely pulls lighter terpenes though
Yeah, I think it would be very difficult to purge solvent at those low temperatures. The reason pulling solvents in a freeze dryer would be more difficult than water (even though most solvents should boil off before water) is because the water never really mixes into a solution with the hash, it just carries the hash with it. Without the thc in the hash actually dissolving into the mixture and increasing it’s viscosity (and surface tension), the water can be easily removed. Once you have thc dissolved in a solution (homogeneous), it becomes much more difficult to remove the solvent. A vacuum oven at warm temperatures works better for that because you need to decrease the surface tension in order to purge the last bit of solvent out.
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