Secrets to 90% cannabinoids (or better) on a short path?

So this is probably a thread worth starting. I have run wiped film and short path distillation on both ethanol and CO2 extract, I have less experience working with BHO as starting material to be honest.

While I have hit over 90% THC and over 95% total cannabinoids on wiped film fairly easily, short path distillation is obviously much less consistent. The highest SPD product I have made tested at 90% total cannabinoids and the starting material was very potent trim that made very nice crude, however, I also doubt that result as it was from a problematic test lab I no longer trust.

Using a newer testing lab, it seems that most SPD product is 75%+ THC, and 80%+ total cannabinoids. Based on public data I have seen, this probably describes about 80% of the distillate that is out there. Popular trends and Instagram have people focusing more on color than potency, so maybe most stuff isn’t that potent?

For those of you who are short path experts with lots of experience, what factors seem to matter most in producing a high quality product? Here’s what I can think of:

  1. Vacuum depth that allows lower distillation temps (ie., cannabinoid fractions distilled <200degC)
  2. Quality of crude extract: does only potency matter? Or trace “contaminants” from over-extraction that can’t be removed by winterization alone, even in high potency oil?
  3. CO2 super/sub, BHO, EHO: any easier to work with than others on SPD?
  4. Going “low and slow” to get more pure fractions? Or does long heat exposure isomerize cannabinoids and lead to lower results?
  5. Distillation heads: the right tool for the job, and different heads or diff packing depending on first/second pass or volatile/cannabinoid fractions.
  6. Winterization (obviously) [Although I have found that wiped film can sometimes produce good product from poorly winterized material]



I might not be the pro here
But since i use deep vacuum (diffstak )
I have~ 5% better cannabinoid content

Starting materiaal the better in the beter out even thou i fraqtion distillate the more different components You have at the begining the harder

Time isomerization My largest rig is 10 liter 6 hours max of heat normal tem control gives me 4% CBN

Winterization at minimum -40C
Sometimes between first and second pass
Highest yield i ever had was 92% :confounded:


Always. On a LS setup, with a silvered straight neck standard design, we regularly see main body in the 170-180°c range, vacuum sub 150 micron

The only contaminants I’ve found to be an issue are heavy metals and pesticides, everything else is just a pre/post processing step

Of course, but as with the previous point, processing rules. A -67°c ethanol extract is typically ready for first pass as is, and if it was fresh frozen flower, I’ve yielded near water clear 95% total Cannabinoid first pass with no processing or additional winterization. There are some factors that come into play with warm solvent extraction that can make pre processing almost impossible. Once you start attacking plant material beyond the Trichome you are asking for trouble.

I’ve found this to be input material dependant. I typically run a rapid first pass, although still sub 200°c mantle temp, and a low/slow second pass.

For sure. The new inverted cup style collects the rejection, this speeds up the process but also lowers purity. Great for a first pass.

Highest potency distillate I’ve ever made was 98% total, 93% THC, on 2nd gen Summit gear, first pass with non-winterized, isopropyl extracted crude


What temp was the iso p extracted ?
98 % is quiet an achievment respect



Thanks @future4200 for your response.

Question for SPD folks: I’m doing a run right now and I think I just realize there may be a distinct yellowish fraction between the “green slime” and THC. Anyone else think there are additional fractions after green slime and before THC?


Room temp.


Was there a lot of biochar left over in the flask after distillation?

Oh ya. Pretty nasty, and the heads and tails we’re pretty gross too


Huh, well so much for the “garbage in garbage out” hypothesis.

The better the input material, the easier the job. But garbage can be refined too


Use a wiped film


Do you ever run into issues winterizing 1st pass distillate?

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No No other than that iT only starts at -28 C flaky substance white in color treu the whole solution

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A lot of this could be lab error as well.
Even with regulations a 10% relative deviation is allowed.
So when a flower tests at 20%, it could be 18-22%, not that big of a difference.
But when it is 90% distillate, the result could be 81-99% with a 10% acceptable error.
The lab will most likely do better then this, but yeah, a scale, a reference standard, all those things have errors themselves, so they add up. Try submitting the same distillate multiple weeks apart and see what results you get.


Agreed treuth is i am ineurope but My process is in marrocco where Any annalitics is extremely hard to find
I work with nugs that used to have seed in them and even though. We deseed 10 % at least by weight we don t get out
So hemp oil is also a by product i have to calculate
As long as the whole process is an illegal activitie(sadly) i just do all the steps and hope for the best winterize,saline/hexane was,florasil and Carbon scrub
and of this year i Will Ad degumming
Lucky for me custumers are happy since i am one of the few that produce extracts
So they setlle for Any thing


Anyone have any thoughts on SPD of supercritical CO2 vs other methods? I helped some friends distill some pretty average BHO using the shittiest Chinese discount glassware, vac pump, and chiller setup. They had it tested and it came back at 89% THC and 98% total cannabinoids, from a fairly experienced testing lab. This was definitely a surprise for me.

My supercritical extracted crude never yields that high of THC when distilled. My hunch is that my distillate truly is over 90% total cannabinoids, but junk that is over extracted by the supercritical process catalyzes isomerization to non-quantifiable cannabinoids. Or, just too much shit that cannot be fractioned out.



I’m convinced there’s something along those lines going on…

I also have a theory that CO2 has the selectivity to grab super heavy terpenes that are almost exactly the same BP as THC, potentially not yet accurately quantified because of their structural similarity. Not sure why butane wouldn’t grab these too… perhaps it’s circumstantial with temps and soak times.


I think your “super heavy terpene” hypothesis is reasonable. After all, cannabinoids are just synthetic terpene products. I also think that the long heat time and high temps of the crude in the boiling flask cause all sorts of reactions that synthesize novel compounds from all the terps and other organics which then have to be separated during the distillation process. What exactly these organics are is a difficult question, I have a notebook with lots of candidates and their boiling points, but there are easily hundreds which could all cause problems in SPD.

Obviously my CO2 parameters are pulling out more polar compounds than subcritical or butane, since the material is darker from what I would presume to be chlorophylls and similar compounds.

FWIW I have been running at 5000psi 65C. I know many people on here will tell me that’s too hot and too high of a pressure, but it gets the job done fast (60-70min run times). I’ll take other recommendations if anyone is willing to share. And I’ll give $5000 to anyone who can get my THC purity of distillate up into the 80%'s I’m stuck running this SPD setup for a while until I can get a wiped film system in.


I’d be willing to bet your CO2 parameters are the culprit behind having issues with potency.

Where are you located? I might be able to get that smooth 5 from ya.