Fresh Frozen Ethanol Extraction: Whole Plant Versus Biomass Trim Yields of Distillate

I’m trying to determine real numbers and parameters for fresh frozen whole plant versus dry biomass trim yield in distillate. I know there are a number of compounding variables like grinding and solvent temperature but I’m trying to get averages. One thing we can hold constant is solvent temperature: for this model both trim and fresh frozen are being extracted at -40F or colder.

As we move forward in the legal supply chain, the larger farmers are headed toward a freshly frozen harvest model for both sauce and distillate. This certainly benefits the farmer, but it leaves the manufacturer with a number of questions. I’m trying to get real numbers on the differences in input material in order to then write contracts that may be long term and that are fair to both parties. This is the way I’m framing the question:

Dry trim is generally lower potency at around a nominal 10%. Fresh frozen whole plant is generally higher in potency at a nominal 20%. Because of the water content, initial estimates are that the fresh frozen occupies about 1/2 the volume (or less) in a given extraction reactor. Does the increased potency make up almost exactly for the loss in volume? If it doesn’t what’s the actual difference.

I’m trying to attach real numbers to this equation: potency X volume coefficient X volume = distillate yield. Any real help that we can all share would be appreciated.


All else being equal, fresh frozen is roughly a 5% return of (weight) weight and high quality cured material can be 15-20% return. Fresh frozen is roughly 4 times the weight of cured material due to water content and cannot be packed into columns like cured material. It is literally 4+ times the work to run fresh frozen for the same output of extract.

Please anyone chime in with different opinions or experiences.


Your estimate of 25 % water content is low 5 wet kg make 1 dry cured kg so 5 times the work is more like iT :cry:


Pfff tough one
Whole plant You mean nugs with sugar leaf ?
Extraction method is cls i asume ?
1/2 wet equall to 1 dry ?
Defenatly not in My opinion
All biomass is cannabis i asume ? Not hemp ?
Frozen as in vacuumbag frozen ? In a
Shock freezer
Or frozen in a normal -18c freeezer at natmospere

Yes. The whole plant includes nugs and sugar leaf. The big farmers only want to strip the fan leaves off. Then the whole plant is mechanically harvested.
Extraction method: ethanol reactor. I’m using Delta CUP 30s.
All biomass is cannabis
The large farms are using a liquid nitrogen flash freeze, technology that is used to freeze burger patties I believe. The bucked plant material is moved down a conveyor and frozen to -25F. It is then bagged and stored in cargo container freezers at -25F. This method is becoming common for the large farms.

I’m extracting at -40F

Oef an etho extraction at -40 on wetfrozen biomass wauw You got balls
Ever tried iT ?
The flash freezing sounds good
The biomass size i wonder

Imagine a ton of water beeing extracted due to the hydrogen bonding
And i wonder If a simple distillation of your ethanol wil get to 96%
If your extraction picks up more than 10 % water etho distillation needs evaporation plates to purify not sure Any wfe can do that

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@cyclopath what do You think ?

No, it’s not.
That would put “whole plant” close to 95% cannabinoids once cured.

That is cured flower, or VERY dry whole plant (which is ideal for ethanol => distillate)
Wet (fresh) whole plant is considerably LESS than 10% potency by weight. I’d put fresh frozen whole plant in the 3% cannabinoids range. Assuming 25% cannabinoids on cured buds. ==> closer to 12% on “whole plant” => ~3% on your fresh frozen.

Which you’ll notice agrees with @TriPro’s 4x.

As far as -40C (or F! :wink: ) being cold enough not to pull water, all I have is @Photon_noir’s -67C for halting chlorophyl pickup.

I’ve heard fresh frozen cryo-ethanol can be done, but for distillate, where the terps are tossed, rather than it seems like the hard way do get the job done.

You’d be far better served by drying you input biomass than freezing. If you want the terps as well, you might consider adding a process step to grab them before ethanol. although I haven’t heard an ideal solution there yet.


@cyclopath So what would the ideal post harvest process look like for the best trim for cold ethanol extraction and highest thc/cbd retention?

How about: Wet buck, rack dry, then nitrogen flush vacuum seal to remove 99.5% oxygen? Is anything being done superior to that process?


I agree with everyone else here, fresh frozen for distillate is way too much work. But if you want those terpenes, you could steam distill them, then dry and grind the biomass, then extract that dried and ground biomass, but I am not sure how well steam distillation for terpenes scales, I only do it for about 8kg per steam distillation of fresh frozen flower.

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that sounds right to me. for ethanol. probably CO2.
fresh frozen makes awesome hydrocarbon extracts :wink:

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Ah. Just read through that thread, and I have similar questions as @Sapes. With our steam distilled flower we inline filter with a little silica gel, and have had no issues with the final product of distillate, but we are also doing BHO.

On the 20% I was referencing dried and cured biomass that is a large percentage of flower. The four times figure seems reasonable. Good information.

Then the consensus is that it would be more efficient to defrost the product prior to ethanol extraction? Grinding the frozen product probably wouldn’t help.

Just to clarify, I’m not putting this strategy forward out of choice. Larger cultivation operations are deciding that it is just not cost effective to harvest and dry the whole plant product. Increasingly as cultivators and manufacturers try to scale the supply chain, the fresh frozen approach to harvest is becoming an alternative. So what I’m really trying to develop are SOPs for dealing with this eventuality that I believe will become more common.

I have successfully extracted biomass at -40 and its only problematic without the right equipment. I was able on a smaller scale to keep water out of the solvent at -40 and leave behind a considerable amount of waxes and lipids as well. But I’ve never considered or had any experience with developing a production line that addresses the supply chain on this scale.

I’m not after terpenes in this model. This is only a process to make distillate. I just don’t see an effective way to obtain terps prior to distillation. I’m thinking that harvesting terpenes would require a separate hydrocarbon production line that had the best fresh frozen diverted to that and was just devoted to terps.

Again I’m trying to develop these numbers out of necessity. Is it a better choice to find a large scale method of defrosting this whole plant product that arrives frozen at -25 and is testing at 20-25% on specimens taken of the dried and cured product before freezing (I’ve seen the COAs) without damaging it?

I’ve also looked at cryogrinding the frozen material which I believe might address the reduced volume of the fresh frozen product. This is no easy process either but indications are that it would reduce volume by a factor of 3-5 X.

Any other thoughts?

I use a paint mixing paddle attached to a drill in conjunction with direct injection of LN2 into my plant material to cryo mill/flash freeze and it does indeed reduce volume drastically. Id say right around the 3-4x mark.

Only thing I can think of is to setup several dehydrators in a smallish room and place your thawed material on large trays throughout the room with the dehumidifiers running full blast. You should be able to thaw and pull out a substantial amount of moisture this way. You can then throw the thawed material in a large industrial dehydrator (FD Heat Pump Dehydrators from Nyle Systems | Brewer, Maine) to remove any remaining moisture. This way you are minimizing the addition of heat which should help minimize any damage.

just to be clear, offering me frozen biomass that I have to dry to 20% of it’s weight before I even attempt to extract it is going to have me going to the guy that hung it in a barn and dried it first.

just because it’s easy for the farmer to flash freeze, doesn’t make drying it the processors problem. nor storing it.

sure, I’ll take your frozen biomass. in six to ten months. good luck storing at -20C for that long and making a profit.

supply vs demand…if nobody wants frozen, they’ll figure that out.

we’ve got so much surplus biomass come harvest, that extractors should be able to pick and choose. at least here in OR.

Edit: and to clarify now that I’m not typing on my phone…

Fresh (wet) frozen makes great hydrocarbon extracts, and can be processed with Ethanol or CO2, or even just water, but in order to provide frozen material year round, somebody has to keep it in a freezer between harvest & extraction.

The most economical way to grow, is outdoors, with a single harvest. we’ve got 3yr old product lying around up here. keeping that in freezers does not pencil out…so my assumption is that cured biomass will continue to be available. Especially in traditionally overstocked regions such as CA & OR


Interested in the Cryo freezing of biomass
I work in remote aerias and having chillers and freezer that pull 135kw an hour is madness so looking in to Cryo freezing prior to extraction
Have a pic ?
What nozzel and Where to get them do You use to spray your biomass

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Best way would be to blast freeze it and then put the material in a freezer container that comes with a generator.

On its way down to -21c