Ethanol Saturation

To what extent do you saturate your ethanol with oil before recovering the ethanol? I am currently using 28 L of ethanol (@ -50F or below) in “batches” and will soak 6-8 lb of material per “run”. Generally I will do 3 “runs” per “batch” but am becoming concerned with the fact that I may be leaving behind cannabinoids behind in the biomass. It wad suggested to me to do 2 soaks on the same material rather than multiple soaks in the same ethanol with different material.


I do not have experience with the particular ethanol extraction you are referencing but based on general extraction principles you will definitely want to soak/wash your biomass atleast twice before discarding. It is very unlikely that you will get all the goodness in the first wash so a second wash won’t hurt. Especially if you are maintaining temps below -50F, the number of washes or length of soaking should not effect how much gunk you pick up, so you have nothing to lose (except for solvent that can be reclaimed) by running material twice. Again this is just in theory as I have not run this type of extraction.

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Your numbers are about right give or take, or at least in the ball park for what I have seen. Keep in mind the solvent to solute ratio in terms of pounds of input material is drastically effected by the initial potency of the input material. Hence, higher potency material will saturate the solvent faster and with less volume by weight than say trim. I good way to check this is to sample and datalog so you know where your saturation points are based upon a sliding scale of input material potency and weight. Good luck to you.


@skanhunt420 the number of washes and the length of soaking 100% affect “how much gunk you pick up”

OP, keep doing what you are doing. To test a specific “run”, after washing with the primary “batch” test a small mason jars worth of the “run” for remaining cannabinoids by washing it with a fresh, cold ethanol. Then recover that test volume and have the residual potency tested. This is only really economical at medium scale operations and up when large “run” homogenization is possible.

It is a fine line between extracting more cannabinoids with a new “run”, and leaving behind cannabinoids from the previous “run”


I am in the process of scaling up right now and just want to make sure I am doing this properly. I receive my material in ~200lb batches and its almost always different so Im not sure how valuable testing a specific batch would be.

I need to scale up to 400lb a week by september at this location and am unsure on how to do it properly after running into this saturation issue. The material I’ve gotten lately seems saturated after a single “run” per “batch”.

I’m gonna risk sounding like a broken record, and suggest you need in-house analytics.

a TLC kit can be had for $160 or there abouts, and would go a long way towards informing your extraction.

you’re asking the right questions. see if you can acquire the equipment to answer them.

$4k will currently get you this critter

which although it does not have a heated injector port or the 12 place vial warmer SRI ships with their “cannabis” 8610c, should get the job done (I’ve had good luck with this particular seller too).


Seconded. How many batches would it take, missing 5-10% of your total cannabinoids, to pay for a $4k GC?

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You can set up a small experiment that might help determine a path forward.

You could set up smaller weight representative batches, by this I mean separate smaller quantities of flower and mix them in the same
Ratio as you would for a production run.

Each of the smaller weight representative batches could be left to soak for different periods of time 10 mins, 20 mins, 30 mins, etc.

Separate each of these smaller weight representative batches into different holding vessels (test tubes would work if your test batches are small enough)

Then, as was mentioned, you have to analyze these samples.

Take the sample that soaked the lowest amount of time and the one that soaked the most amount of time. How much did you lose in total potential product?

On the other hand, when you compare the two, how much extra cost did you incur for getting rid of undesired components?


I have only washed a thousand lbs maybe but I didn’t worry about my saturation level as long as the material was rinsed with clean cold solvent before the centrifuge. My yields were the same as post winterized room temp bho extraction. I do one soak for 30 minutes and I think the most concentrated my solution got was 10:1 since I was always adding a little solvent.


I’ve been asking the same question, as others have said it is very dependant on the quality of starting material. I did come across this article that did some testing for us with soak times and temps for freezer and dry ice.

Edit: talks more about yield vs temp and time than about saturation tho, so might be slightly ot.


that rinse before the spin cycle seems like it might be important…


I did a small test similar to your suggestion. I took 82.5g of material that I had ran the day before and added in 1L of -50F ethanol. I then let that soak for 10 minutes. I then filtered out the material and keif and roto’d the ethanol. Although my scale was acting a bit odd, it seems that I pulled ~5g of material. This puts me around a 6.06% yield. To me, thats absolutely worth it.

I normally do the 8lb per 28L. So I figured I need to do a second wash on this material.

My current plan is to homogenize all the material I receive from each client into their own batches. I will then take 100g sample of each batch. My plan is to soak it into a proportional amount of ethanol (8lb : 28 L ratio) and then centrifuge and filter. I will then repeat this process on the same material. I will roto these samples separately and guage how much I am to gain from a second wash. For lesser material, I will do two tests as well. However, I will instead do 100g in ethanol and then 200g is the same amount of ethanol and compare the loss.

I feel that there has to be a better way to do this but I am unsure. Ideally, I would not like to end up with 28x2 (56) Liters of ethanol per 8lb batch. It would take me 3 hours to roto all of that and would only be going through 8lb. Based on my current math, I need 22lb of material extracted to distill into 1L of finished distillate. This puts me at 9 hours/day for 24 lb. This only gets me 5 liters a week of distillate.

The last material I ran, I was able to get 15-18lb of material into 28 Liters of ethanol. Makes me question if I lost a lot of yield by doing it this way but I am unsure.

As a last question, what can I do with all this information from the tests? I will have the amount of material extracted, the amount of ethanol used, the yields from first, second, and potentially third passes. Could I turn this into a graph or chart for saturation points based on first-pass yields?

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A rinse into another batch of clean, cold ethanol? Can this soak be done on partially saturated ethanol?

it seem like you’re currently doing your math based on raw yields. I’d advise you to look at absolute cannabinoid yields instead. because the potency of your extract varies as you deplete the cannabinoids (at least with rm temp solvent).

have you had your crude potency tested? 65% cannabinoids is pretty standard if you’re doing it nice and cold. possibly 70%. does your biomass come potency tested?

6% yield on a second pass seems pretty high. unless you were running trimmed flowers at ~20% or better. I’m also guessing that’s probably closer to 4% cannabinoids (60% potency at best, possibly 50-55%).

I’d also be suspicious of losses to the roto flask at 5g. unless you left extra solvent in there to get it out. in which case you again need potency to make sense of things.

what % raw yield did you get on the first pass?

Did you have a potency on the last 15-18lbs of material? it wouldn’t really mater, because you don’t have a weight, but assuming you did, and a potency and weight on your distillate, then you could know your percentage yield, as cannabinoids, not just “oil”. if you sent the crude off for testing, you’d know your efficiency to crude, and from crude to distillate. both are useful to monitor.

yep, extra solvent means extra solvent recovery. which is why folks choose to run the same solvent over multiple batches of material. there is a sweet spot. exactly how you chose to skin the cat, seems to make a difference on where that sweet spot is.

Taking anyone else’s word for exactly where the point of maximum return is, is not something I would do. Because chances are nobody is doing it exactly the same way you are…

as for the rinse, I’ve yet to look into it. it just struck me as a clue that should be highlighted. in case it was important. asking @Montanadabman is probably more relevant.

edit: this is why i’m constantly harping on about the importance of in-house analytics.


I have never had my crude potency tested and my material does also not come with potency results either. The material I got from this client is a mixture of nugs and trim from a trimming machine. It seems VERY potent just based on smell and feel. I’d argue over 15% forsure. With my cold ethanol extractions, I generally get around 70-75% yield from crude into distillate. The distillate is always low 90% potency.

As for the measurement after roto, I removed all the solvent possible at those temps and then weighed directly in the flask.

I am certainly considering buying some stuff for in-house testing when I can afford it. I have a few things to buy prior. Considering a secondary roto at this point so that I can just do two soaks and not worry about it.

I feel like there has to be a streamlines way to determine how many washes I can do in the same ethanol or how many times I need to wash material with ethanol. I’ll be thinking about this a lot the next few days and see if I can think of a consistent way.

If you have suggestions, Id love to talk it over more. It helps me think.

Edit: The #1 piece of information I want to figure it out is what % cannabinoids will saturate ethanol and at what point is a second wash necessary. I wonder if there is a mole ratio floating around somewhere.

with only potency on your distillate, it will be fairly hard to figure out.

you can tell when you’ve got all the cannabinoids though. when you add water, the cannabinoids louche. so once that stops you’re done.

edit: Search results for 'louche' - Future4200


Can anyone give me a min-max estimation as to the plant to ethanol ratio? Suppose your max is the most potent bud, say 25% and above, and your min is leafy trim of low quality, that we assume is 1-3%. What volume would you use in each process? I’m trying to make an educated guess based on my process.
Second question - being as that the second wash is there to collect the leftover, would half the volume of ethanol do the trick? After all, the remaining amount has been reduced considerably

@clandestinebynight have you read the Bucket Tek thread?

have you considered acquiring in house analytics?

Min would be that required to cover the material. Max would be that same amount, performed three times. amount required to cover material varies by grind. 1.5-2lb per gal is a reasonable starting point.


I follow the bucket tek actually :grinning: but, sometimes, I process trim, and was wondering if I can cut down on the solvent.
No in house analytics for me! Everything I do is primitive, “street” production. I considered TLC but, it’s currently a pipedream.
Thanks for the input! It really helps. I will also examine the louche concept.

I can’t currently find the either of the “old school” cannabinoid isolation protocols I recall reading in the distant past. One or both used the addition of water to the eluate to determine when enough solvent had been run over the material. If it louched, you needed more solvent. once adding water did NOT cause white precipitate, you were done.

I have an issue with my internal filing system: I remember and file what I’ve read, but fail to attach a reference/source to the information waaay too often. can be a royal pain sometimes…