At what temperature do specific hydrocarbons fail to extract cannabinoids?

I’m interested in knowing the temperature at which specific solvents begin to fail at extracting cannabinoids — specifically, CBD — efficiently from flower.

I am trying to mitigate isomerization of lipids/cuticles/epoxies/etc. as much as possible.

At what temp does hexane(s) begin to inefficiently pull CBD? Pentane? Ethanol?

All help greatly appreciated.

Fail? when they get slushy right before they freeze. ish.

Get less efficient? possibly as soon as you wander away from just below their boiling point. Except for CO2 which isn’t a hydrocarbon, but was defined as such by the Oregon legislature for awhile.

I’m guessing you’re after “what temperature can I use to avoid pickup of undesirables without loosing cannabinoids”. As that depends on the solvent, and to some extent the starting material (certainly the water content), you’re asking an enormous question.

For ethanol, you’ll find that -80C works beautifully, but is overkill. -40C works well, but still picks up a little in the way of off target. More so the longer you soak.

With low MW hydrocarbons like C3 & C4 (Propane, Butane & isomers), again -80C works very well to avoid pulling ballast (unwanteds, stuff you’re gonna remove later), but requires longer incubations to get maximal cannabinoid yield. Only other temp I’ve tried is -30C which is just what my chiller is capable of. Works great. Does pick up off target. Soak time and volume of solvent are still variables that need to be optimized. And optimal values will be material dependant.

with C5 & C6 isomers (pentanes & hexanes), I’ve seen zero data here or elsewhere on their relative efficiencies for our target & non-target at differernt temps…you’ll presumably see exactly the same trends, the warmer the solvent, the greater it’s carrying capacity for any target.

Most folks don’t have in house analytics, so at best have a couple of points on the curves you’re after. If cannabis was not still schedule 1, the data you’re looking for would be readily available…

Edit: on the other hand there are lots of very smart folks here, we might get lucky and find someone who has gathered that data and is willing to share. eg @Photon_noir


Yes, a better question for my desired answer is what you proposed.

Thank you for the reply. I was having the hardest time finding data on C5 and C6 alkanes… now I see why… that data hasn’t been established yet.

You rang, @cyclopath ? Oh. Well here, @ErrlDabbins303 :

I don’t feel there is any temperature at which hydrocarbons or ethanol actually fail to extract all the cannabinoids from flower, given that all the trichomes make contact with the solvent for enough time to allow the terpenes to do their cosolvating work, which is usually a very short time, indeed. This cosolvation also eliminates any possible “inefficiency” in pulling cannabinoids with these solvents. If they were pure cannabinoids, sure, I would say you want solvents to stay above 0°C, but they aren’t… certainly not from flowers.

Therefore, the type and degree of grinding, temperature (with regard to condensation of LP gases [aka: typical hydrocarbons or alkanes, usually n-butane, isobutane, and propane] to liquid form), and agitation (in the case of ethanol, which far less permeating at low temperatures than alkanes because it is light-corn-syrupy rather than a pressurized liquid) all play roles in with all or their specific solvents’ abilities to rapidly dissolve a “quantitative” level (i.e. “most”) of the cannabis resin, and thereby, the cannabinoids.

For butane/propane, one never need go lower than -60°C in typical column or tank stationary bath and/or rinse type extractions… and that is for fresh frozen flowers. For dry flowers, and one prefers they are as cracker dry as possible rather than “cured”, one need only to go as low as -30°C or -40° to be safe (i.e. avoid too much water/color pickup). However, all this very much depends on whole vs broken vs ground herb. NEVER grind fresh frozen, and try to freeze it as whole and fluffy as possible. I would argue never to grind dry material either, but instead break it down into quarter inch size pieces with your hands or a cold hammer mill or something. That said, the rule of thumb is thus: propane pulls less color than n-butane for a given temperature… and isopropane, being a sort of 2-D version of propane if you will, is somewhere in the middle, BUT isobutane at temperatures above -40°, and in some cases even above -60°C, tends to produces slabs with a greater tendency to microcrystallize or “autobudder”.

As for ethanol, most of this follows except temperature and agitation. In order to avoid picking up ANY chlorophyll, no matter how big an asshole the supplier was to the material, use 190 proof ethanol at -67°C or less. To avoid just fats and waxes, for the most part, temperatures as high as -40° are acceptable. Regardless, since ethanol is more dense and viscous than the aforementioned hydrocarbons, stirring or agitation is usually required. As usual, try not to beat the living shit out of the biomatter. Doing so will increase green color pickup (above -67°C), and will result in production of lots of very fine sediment that can be “troublesome” to “impossible” to filter out.

Last I would say that the longer n-alkanes, such as n-pentane, n-hexane, and n-heptane, for the most part follow the same rule between propane and n-butane… that is to say, each increase in carbon number tends to pull more color for a given temperature. Also, their isomers fuck up the whole show and cause you to lose all process control… unless you can consistently acquire the same mixture time and tine again. Usually these longer alkanes are reserved for producing the famous (or infamous) RSO, when one desires better color than ethanol can normally provide (e.g. without dry ice or a cryofreezer), or a generally stronger “oleoresin”, that is: vegetable oil[epicuticular wax, veg oil, glycerin, lecithin,etc]+resin.

Sufficiently summarized? I ignored your use of the term “epoxies”, as I know of no stable epoxides of any importance to us in cannabis extraction, and I ignored the entire sentence really, because none of the items listed are significant isomerization products (nor are any cannabinoids, in case you wondered) during these, generally cool or cold, extraction processes.


Is it ok to start with anhydrous ethanol? I would assume that it would pick up some of the water along the way. Would that be a problem?

It is best to start with 190p, because 200p behaves like a non-polar (iow, it pulls some lipids) before it picks up the extra water. You can always add the water before starting, by humid air or directly with liquid water.

What would be the benefit to adding a % of isobutane to your solvent mix? It feels like butane grabs cannabinoids, and propane picks up terpenes. Why do folks add isobutane to the mix? I have recently been curious about running pure isobutane as an experiment, but autobudder doesn’t sound desirable atm.

I typically do a CO2 expanded etho and the water in the etho converts to gas when the dry ice gets put in the solution. That is what always made me think to use 200proof

How on earth is water being turned to vapor at those temps? Solid maybe

The water in the 190 proof alcohol. I typically start it at room temp and bring it down to temp with dry ice

Back in 2013/2014 I did all my extractions with isobutane(r600A) due to color improvement and lower boiling point being easier to recover. I never had any potency or flavor issues.

IMO, r600A is basically butane that acts like propane, although I’ve heard others complain about r600A. I preferred r600A over 70/30 simply because there’s no mixture to disrupt.


@cyclopath has the same question I do. The vapor you see is likely water in the air freezing into droplets by contact with cold gas, not liquid born water evaporating.

As @Shadownaught said, I also do not like mixtures for the same reason. Using it alone, it must be very cold to avoid autobuddering. It behaves like butane in its pulling of cannabinoids and propane in its pulling of terpenes, for the most part, but if not kept well below -40 (-60 is better), there is a higher probability of autbuddering.


I run straight iso and passive, I never have a problem with autobudder

I transfered over to standard iso instead of blends a couple years ago, myself. It runs great color, far more than acceptable recovery rates, all the above. I heard it was originally a propane, removing a chain carbon (if I’m correct) giving it the same chemical structure as Nbutane. But, a completely different molecule shape. Also, I love my hat too. That ish is extremely comfortable

As photon noir advised never to grind but to break up the buds in 1/4 inch pieces
I use a garden leaf vacuüm machine of Wich i have blunted (made les Sharp) the rotor blades runs kilo s a minute yust great


O and on topic
I have extracted with hexane at - 86C and still pulls way to much aka black rso to much

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Could be, and don’t quote me but it’s possible…maybe? The amount of heat released from condensing atmospheric humidity could be released and vaporize the water? It would take a lot of energy to raise the temperature of the water then boil it though.

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Thanks, this was what I hoped to hear. Trying to keep a consistant blend is a pain with the n-tane and propane, but I love the color and terpenes that propane brings to the table. Were running plenty cold for isobutane.

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