second pass intel

Have an oil that is at 85% and would like to get it up to 90%. I ran a second pass on the oil after getting test results back that it was at 85%. During second I had three balls on my cow. The first one I ran into until I hit 200 microns on my reader that was mounted to my condensing arm. Once I hit 200 microns I rotated the ball and started pulling in to the second one. On my load flask a drew a line at 15% net weight and once I hit that line I rotated the cow again to my third ball. After testing all 3 balls I found the lowest percentage was the first and the highest was the third. The first ball was at 80% the second ball was 84% and the third was at 85%. The mantle temp was at 190 the vape temp was at 160 on average. With all that said does anyone have any idea with those perimeters why I saw no increase in my delta 9 % and do you have any tips for how I should be running my set up differently to get better %.

What kind of still head are you useing? Have you been able to get a better vaccum draw.

I’m using a new Lab Society high efficiency set up for a 5 liter load flask. I was able to with my old head but not by much. I’m wondering if I pulling too hot though.

it would be useful to overlay the chromatogams. which is one reason developing a good working relationship with your 3rd party lab is so important. especially if you don’t yet have In House analytics

There are two possibilities, you’re pulling to fast, and not getting separation, so you’re pulling over the same ballast that you pulled the first time. Or you’re running too hot, and actually degrading your cannabinoids rather than purifying them.

You could tell these apart yourself if you had a GC or HPLC. with a test on your leavings, and an obliging 3rd party lab, you might also be able to figure it out.

note: “too fast” is essentially equivalent to “too hot” and both are related to vac depth.


fair enough what would be indicators as far as test results that its going to fast (hot) seeing dealt 8?
How much of an increase do you see on average between your first and second runs?

you’re looking for any change in the cannabinoid profile or total cannabinoids.

If the total mg THC (weigh of input in g x potency in mg/g) in the system changes, you’ve degraded some of it (too hot). if it remains the same, you’ve simply not achieved purification (too fast). if your lab says you’v gained some, you’ve learned why smart folks do it themselves. :wink:

If you see other cannabinoids (CBN, CBC*, delta8 THC) appearing, you also know you’re over cooking things.

*If they tell you you gained CBC, they’re wrong. Find a new lab.
THC Imposters (Isomers)

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I second @cyclopath with the distilling too fast and not good separation comment. The resolving power of your still rely’s on theoretical plates. The less you have the more “simple” the distillation becomes and “less fractional”.
A packing such as glass rings or ceramic saddles will improve the separating power if the distillation. Lastly removing the lowers completely and waiting for your vaccum to improve to alteast .5 micron before ramping the heat up to collect the main body helps. I dewell around 120-130c boiling flask temp until I see the tell tale sign of vapor pressure drop in the system. Then I ramp up and watch my head thermometer around 150-160c. I wait till the temp stabilizes . Usually around 160c. When it’s stable you are collecting a "fraction " I collect the main body fractions from 160c-180c . Tails come across 180c- 210c . Your vaccum source and the vapor pressure in your appearatus will be the limiting factors.


I can see adding packing going both ways. more reflux gives greater resolving power, but also mean longer residence time at temperatures @QTP refers to as blasphemous.

I’d love to explore that more somewhere… maybe under Short Path Head designs?

or just @weave it in here :smile:

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In comparison to your first pass run, how long did the second run take you? I mean by this if you could say measure “drips” per minute going into any of the flasks would you say the second pass was the same as, slower than, or faster than the first run?

In my experience as you begin to tweak things towards higher purity it becomes increasingly important to slow down the evaporation of the compound as a whole. I run much lower pressure than you have cited and in that case the rate of evaporation dramatically impacts purity as there is no fractioning possible by glassware design at such low pressures - it is all temperature at that point. Coaxing the compound up to collection is pretty important because at 85% pure (impressive) the unwanted fraction is so close in boiling it is always on the edge of overlapping the edge of the first fraction if you think of the two fractions as clouds of vapor you are trying to expand up to the collection point. When the pressure is below about ten microns I think of it as chasing a film up the glassware.

For troubleshooting your question the missing data point for me is the rate as I mentioned that you see things coming across compared to the pass that produced the 85% distillate.

where do you have your vac monitor connected to your system? Your’e able to get down to .5 micron? What kind of pump are you using?

As far as the rate of witch we are pull I’m think it was slow but not by enough. The first pull that produced the 85% was pulled at 196c and second as I mentioned was at 190. My average micron on first pass at 400 measuring it for the condensing arm and on my second on average 150 micron. So from everything I’m gathering from here (thank you boy btw) I need to be pulling slower which in turn means a lower temp.

@cyclopath so just looked at my test results and they do show CBC at 6%. seems high? What about CBC showing up makes you think a lab is bull shit?

because if it wasn’t in your crude, then it’s almost certainly not CBC


I gave you a link to follow…here it is again.

current best guess is that it is a delta9 degradation/isomerization product. possibly delta10 or 10a THC.

maybe check out this thread as well: Where oh where has my potency gone?

Edit: not saying the lab is bullshit, just that you should find one that is more knowledgeable about distillate. They should have noticed that the retention time was not quite right, and admitted they didn’t actually know wtf it was.


I have pirani guages on the intake and forline of the diffusion pump, I also have a thermocouple guage mounted before the cold trap on a valve. I use it to verify the the diff pump can be started.


Good deal!