CBG not extracting with heptane?

So I’m running my first CBG biomass that’s supposed to be 14% CBG and my yield is crazy low.

Does anyone know if CBG doesn’t extract well with heptane and if it must be extracted with ethanol instead?

1 Like

Haven’t tried with ethanol (yet) but I’ve got a CO2 lab I do business with that is currently running some 8% CBG biomass and he was complaining about really low yields too when compared with same % CBD biomass.

1 Like

The person I got the biomass just said this so the low yield on co2 makes sense

“When I asked the Crawford’s about extraction they said Do Not use CO2 because it didn’t work well”

I also just taked to someone that said a liquid-liquid extraction with methanol and heptane yielded very low too.

Looking like hexane/heptane and co2 are a no-go for CBG.


Potentially heating the heptane and extracting with a Soxhlet apparatus will yield better results? I can imagine if a hot extraction works that as it cools you may get room temp precipitation.

Excited to test this out, I have some nice large glass soxhlets I’d love to pull out and use for R&D, and lots of steel to build a large unit.


The least your solvant is polar, the least you will get cbg out, specifically. In addition, there seem to be som co-solubility issues.

I got one cbg biomass that was cryo extracted, and the extract came out with a cbd profile.

I compared 4 solvents of different polarities (methanol, ethanol, acetone, and hexane), at two different temperature (room temp and -30c), using large liquid:solid ratio (about 40, large enough for analtics). Extraction in acetone/methanol/ethanol give similar results (a slight win for methanol, but not sure if it is not an artefact…). Their efficiency decrease by 10% at -30c, especially regarding cbg.

Hexane is already slightly less efficient at room temp dealing with cbg (-10% regarding methanol), ang gets even less efficient at -30c (-40%,).

So the key is to tune solvent type and/or properties (higher temp and/or pressure), longer residence time, higher l:s ratio. Other undiserable may likely come together.


Please excuse the dumb question, but why isn’t anyone extracting with n-butane and propane? for cbd and cbg?


I’ve used n-butane for CBD not sure what yah mean

Just having a hard time finding information. I’m considering a small scale processing setup for our few farms, and I really want to see what n-butane and propane produce.

Do you have any results or pics?

1 Like

There are lots of processors doing so for CBD, in conventional conditions (below room temp, and below 10 bars).

1 Like

I think the biggest hangup for hydrocarbon extraction in hemp is the fact that, with the exception of a few systems very new to the market, butane doesnt scale up very well. More throughput for butane generally means scaling out not scaling up, more tubes and tanks not bigger tubes and tanks. So its not that it doesnt work it just is below the scale of most hemp proceasors.


Agreeeed. We’ve seen 4" be really successful the bigger yah go the trickier it gets to extract it all. Never had anything bigger than a 6" work well

1 Like

I had avarage results with hydrocarbons (pentane and hexane mainly) and CBG and very good with ISO. My recent CBG crude clocked at nearly 80% CBG while with pentane and hexane couldn’t get past 50% and there was still about a halve left in the biomass while ISO extracted flower tested at 0 CBG left.

1 Like

To me the exciting benefit of hydrocarbon for this would be CBGa production rather than CBG. Would a good cold CRC hydrocarbon run(80%+ purity) crash out? Can we easily isolate CBGa like THCa? I can’t wait for my local farmers to start harvesting their new CBG genetics.


We are getting 85%+ cbga with Etoh.

I haven’t personally run cbg with butane yet but I’ve talked to a few people who have with poor yeilds.

Met a guy at last week that is doing 1000lb a day with butane so there’s some scalability.


I think it’s safe to say that cbg is not particularly attracted to non polar solvents


Just an update that I re-extracted the cbg biomass with ethanol and yield was way better.

Based on the new numbers I’d say that heptane only extracts 20% of the cbg on biomass.


This explains my absolute shit yields in LLE

Also this means that anyone running LLE into alkanes is likely losing minors.


I have had terrible yields attempting extraction with 70-30 n-tame/propane and with 100% n-game.

1 Like

Maybe heptane is no good for extracting CBG but wouldn’t that mean it is very useful for purifying a CBG crude to make an isolate/thc free?