Solvent to Biomass Ratio

I’ve been going through too much solvent lately, which means a lot of trips to xtractor depot :-1: and I’ve been trying to diagnose why my solvent recovery rate has been so low (50%). I’m trying to be conservative with my solvent usage at this time and figured it would be a good time to ask others how much solvent they are using per pound of plant matter. Originally I heard 10 lbs of solvent per pound of plant matter, but I quickly learned that’s excessive. I’ve been doing 2 lbs of solvent per lb. of bio mass for shatter, with good results. What’s too low? 1/1?

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Careful to elaborate a bit more? What kind of solvent are you using?

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Are you baking (120*f) your columns and recovering to a full vacuum before dumping out the plant material?

what if your vac gauge isn’t lying?

before I showed up at my current location, they figured out the haskells in the closet were leaking only because the solvent use was off the charts.

50% recovery should involve all sorts of cold/wet spots when you’re done.

I’m now routinely achieving less than 5lb loss on a 100lb dump…
the guys running the other rig are still running around 12-15lb loss.

all about the plumbing… (thanks @Soxhlet!)


Can you recommend a safe way to bake my tubes if they are not jacketed? I feel like a “hot vapor loop” on my recovery pump is not very good for my pump. How about heat trace cables?


Heating electrically could work. years ago when I was first tinkering around with building cls I experemented with heating a standard shatter platter with a bvv round silicone heat mat.
It did work, but when we started using jackets and heated water our recovery rate went up by about 10x. It seems the thermal mass of the h20 and increasesd heat transfer via jacket is far superior to the electrical heating I experemented with. You could try wrapping vinyl hose around the outside of the spool to make a “poorboy” jacket.
ps: Always ground your electrical systems!


Fuck yea!


70/30 butane propane

I’m not baking my columns, I’m not familiar with that. Once the BHO starts to muffin up is when I turn off the system, dismantle it, and dump the plant material.

You can valve off the column and heat it/use your recovery pump to bring it to a full vacuum. You need to have a recovery line going to the top of the column as well as the collection pot. That will scavange all the residual butane in the system.


So were the pumps replaced or repaired?

You’re asking if once we discovered we had leaking pumps, we did something about it?

Yep. New seal kits, and a sniffer with its nose in the closet and it’s alarm where I can see it.

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Hey guys can we get an answer to OP’s question, feel free to chime in on what you use.

How much solvent is recommended for extraction?

(Amount of solvent needed varies depending on temperature and biomass potency)

N-Butane - xx lbs per lb of biomass
Iso butane- xx lbs per lb of biomass
Propane- xx lbs per lb of biomass
Ethanol- xx gallons per lb of biomass
Other solvents-


One gallon per pound biomass for ethanol. Although you can get by with less by re-using the solvent over a couple or six batches of biomass (potency dependant).

For 70/30, I’ve been using about 5lbs per lb of biomass. I could probably cut that in half if I packed more material in the columns.

Edit: those ratios are essentially “covering” the biomass as packed into the reactor. be that a bucket, a column, or a 'fuge. Grinding or packing the biomass tighter would allow for less solvent. neither are near saturation at those ratios


Ntane and iso will probably be about the same with a 4-5 lb of solvent per lb of material (dry)

Propane, I assume will be the same or more? I haven’t used straight propane yet.

Ethanol will depend on the setup being used. Reactors work well, use the most. Counter current, similar to standard cls, will use less but you’ll have to get the last of it out of the material. Spinner would work. Collect the “warmer” spin off and dehydrate it later and combine back with the good ethanol


I used 1.5 gallons for 5 pounds of biomass yesterday. I reused the solvent 4 times, adding about 250ml of fresh ethanol each run. My material was 8%.



1.25lb biomass in 1.25gal EtOH
4 times
with 250ml thrown in as a top-up 3 times?

Column or bucket?

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Essentially, yes. In a SS bucket. 10-minute soak time with chunks of dry ice thrown in as well. Biomass was spun off in the panda and the solvent that came off was re-used. Is there an advantage to using a column?

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Hell no columns are a lot of work


I did a 10min last time. Imo, if cryo temp, you can wash longer and not have any bad stuff get extracted. I’m gonna try for a 30min soak this time.