Hey All 
I’ve run into a predicament.
Run 1:
66 to 291 microns averaging 131
176.6 to 181 averaging 179
Got me 82% cbd.
Run 2:
23 to 44 microns
174.3 to 177.4
Got me 77% cbd
Am I miss something here? My thought process was to compensate for the vacuum pressure being so low and lower my target VT. What the hell happened? BF was sitting at 188 on both runs. Should I have gone hotter instead of colder? Wanting my vt to rest at a range of 180 to 185? I’m on a short path.
Any help is much appreciated 
send them out for testing again.
those could be the same number.
your samples may not be homogeneous.
you may have switched flasks early or late.
you might find a run or 3 with summit’s fraction finder to be very informative if you can get ahold of one.
I tend to pull my samples from the middle of the run. Is there a suggestion on how to do this properly? Is it best practice to homogenize the batch?
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Doing that today. These are two different runs with different batches but I expected the potency to be somewhat similar. Am I right in following my instinct to lower vapor temperature or should I have gone higher?
They are somewhat similar. They might even be identical. Not being familiar with the lab you’re using nor how you sampled ie: was the sample representative, it’s impossible to know without repeating.
I’ve not run molecular distillation with analytics on the output stream (eg arometrix fraction finder), so I don’t know what sort of variations in potency one might see during a fraction, but cutting early or late can certainly affect potency.
I have run lots of ethanol distillations with a monitor on the output (proofing gauge in a parrot), and you can certainly induce variance in proof based on how you’re running the still.
Sample was homogenized prior to submitting and I use New Bloom Labs in Chattanooga. We are re-sending the samples to a different lab and comparing the results. I’m just baffled at this point. I’m not sure if we have a fraction finder in the budget at the moment, but I’ve been running etoh crude for a little over a year on the short path and followed what I had previously done (slowly ramp until lower boiling volatiles are stripped and vac stabilizes and vt drops). The runs prior to this were never below 80% until this guy.
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I split my main fraction into two amounts to mix with 2 different terpene varieties usually. The first half I pour out of the flask (the last portion to distill before tails) always tests higher by a few %. It’s also always a bit darker in color.
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There’s multiple potentially confounding variables that could be at play, especially from batch to batch.
If you don’t know your input thc % then it could easily just be an in process issue.
Hell an 8% swing could be normal just in starting materials impurity content once magnified by concentration procedures.
If there’s even slight changes in your winterization time, temperature, or even if a filter wasn’t set properly some wax and fat may have come through.
I’d say really check into your winterization procedure first, then extend it/further chill it. The only thing that would effect end potency would be either much more “tails” coming through; or else something further back in your SOP.
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Winterization step is solid, but I’ll check in with my techs to see if they are running centrifuge tests prior to giving me the crude. There is a possibility for there to be a potency issue if I’m not fractioning too soon or too late as @cyclopath mentioned. I’m curious what other vapor temperature ranges you all fraction for cbd at and whether or not my vacuum pressure plays a role in deciding what my target VT should be.
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