In the process of having a walk-in freezer built for the lab, I was wondering how cold does it HAVE be for storing fresh frozen? I know it should be at -20 to -30, but can we get away with -10?
My understanding is -10 should keep your FF in good shape but the length of time it will stay good is less than a -20 or -30 freezer.
You need to keep your FF frozen at all costs, and never allow it to start to thaw.
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You can keep it at any freezing temp to store, but you really want to deep freeze before you blast if you store it warmer. That way you can get away with a smaller -80 cooler that just holds a day’s biomass.
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Im just trying to keep the cost as low as possible for the build out… the contractor said going -20F will pull moisture from the concrete… which makes sense …and they need to put something over the concrete floor to insulate it… so the cost goes up…
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I was assuming your temps were in C but now I think you meant F.
Make sure that is crystal clear with all vendors and contractors so you dont over do the chilling cause -20f is almost -30c.
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That is a great insight, I have a freezer truck that goes down to -20c and a 27cu ft lab freezer that does -80c, i use the truck for bulk storage and packing columns, and then use the lab freezer as the storage for product to run next.
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The HVAC system for the walk in freezer should have something to accommodate for condensation. Hence frost free freezers. It’s all good as long as material stays frozen. Then winterize your run lot at -60,-80 or colder. All of us here would love to have a walk-in freezer at -80 but that’s very economical.
So - yes, you need to seal your concrete in a different way to make sure it withstands the constant temperature fluctuations. You want a smooth finish - and you want that finish to be WATERPROOF - this is so you don’t have seepage that leads to the concrete breaking down from freeze and thaw activities. You should probably be using a concrete sealer anyway - because you’ll want it to be easily cleanable AND to look nice. 
Its legit like an extra $100 per 450 sqft - if that’s breaking your bank… let us discuss other options. He may be asking you to go with a concrete vapor barrier (what most off the shelf freezers come with) but that would be for new construction (are you pouring the slab, if not you cannot just randomly add vapor barrier, unless he’s pulling the slab up…)
And I suppose its possible he just wants you to put a floor insulation panel down (it is basically the same as the walls…with like an extra sheeting on top, usually like diamond sheet metal). I haven’t done this in the bigger walk-in’s I’ve built. I go with the concrete sealer and I monitor for leaks/cracks/etc.
How big do you need your walk-in to be? Off the shelf may be cheaper if its a smaller unit.
I’d never want a -80C walk-in freezer… cause I hate walking in a -40C freezer and -80C is that much worse. x.X You shouldn’t need it colder if you just want everything to stay frozen. USP for Frozen is -20C with excursions between -15C and -25C that should do it, until you are ready for the next step and then have a smaller unit to drop temperature further if you like.
Let us know what you decide!
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I’d u ever do have a freezer shut down and catch it before the material is a goo factory spread it out to dry for week under fans the. Refreeze on dry ice before you run it …at least you can salvage it if you catch it get it fast enough
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You might need two small -80 freezers. They are built to keep shit at -80 not freeze shit to -80. It takes a while to get there from -30. YMMV
I’m going to go ahead and say 90% of fresh frozen is processed like shit. Freezing cannabis slowly or in bags is dumb as fuck. Fresh Frozen seriously isn’t worth it, unless it’s FLASH frozen with ln2 or a chamber.
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Decreasing the temperature and encasing in ice seals in the terps. So long as the material stays frozen and the trichs stay encased in ice, temp doesn’t matter.
You need the blast freeze temperature to make sure your material stays frozen and the trichs stay locked in ice during handling and up until the solvent hits the biomass.
Bro you do not want ice. Ever. Like anywhere on your material.
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You don’t want freezer burn, but what exactly do you think happens to the water content of the biomass?
If you do it correctly you sublimate it out. You just gotta be cold enough.
Idk about you but I seal the ff biomass in vacuum bags and freeze. Ain’t shit sublimating out of there.
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Oh good lord no. If he’s building a giant freezer, he should at least invest in a low end ln2 bucket + freeze dryer flash freezing method. Atleast for his material, or as a service for fresh bucked.
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Most commercial freezers also have multiple defrost cycles throughout the day. So, maintaining -20 isn’t gonna happen 24/7…we get up to 0 C during defrost cycles 4 times a day for at least a half hour.
As well, the old quarter on top of a solid cup of ice is a good way to see if your temps ever creep above freezing.
I used research freezers with data loggers for temp
Flash freezing is best, then you just have to keep it frozen and sealed. As long as it doesn’t defrost, it’ll be fine. If it defrosts, or is frozen slowly/not cold enough/incorrectly will rupture the cell walls and have a lower quality extract.
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