Recognizing tail fraction during spd

I am about to do my first run and I have been wondering how to know when to switch over to the last flask to capture the tail?

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Usually i keep an eye on the color that is coming over after the vigs. That and the temperature will start to rise, but that can be also mantle/vacuum dependant.

Usually the distillate will get a more orange or red color.

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get a vacuum gauge that give you a pressure vs time graph. makes it easier to see patterns

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Your head temp and vacuum should change

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I’ve found tails to be the most frustrating fraction to identify. During a quick first pass it happens so soddenly by the time you see it you’ve already mixed it. I generally consider this fine on first pass, and just aim to catch as much as possible. Vac depth during a deep vac second pass it’s a lot more subtle. To me the vac changes are so slight they’re unnoticeable. And the best way I’ve found to work is by using the key from Summit. I used to think the device was bullshit. For starters I was given it with zero training. And it just looked like a thing that sat there. But by using ultra low vac it has become super apparent what it does. During heads you can see a blend line that happens where a fraction builds up between the ribs. Usually I identify a green color. This I allow to slowly exit on its own. Then I push the main body a little once the heads is fully done. I allow main body to go faster then heads because it’s thw fraction I want the least damage done to and it’s very long. Tails will then bunch up on the key. First as a solid yellow color, then an amber. I typically catch the yellow and amber together. But I see them as two separate fractions. The slower you go the more apparent this is. I’ve placed a time lapse on my key before to watch the blend in a faster pace. Seeing a video such as this will help you identify it. Once I see it, I chapter separate and usually crank it out quicker. The slower you go toward the end of mains, the more you can starve off the tails from rising… but it’s very time consuming and I don’t know how viable test results are from the concept, but I have done it. Your temp and vac depth will drop quite a bit to do this.

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When people talk about heads, mains and tails, what specifically are we referencing?

Are the heads your volatiles such as your solvent, phenols, etc and then your main body is your cannabinoids, then what are tails? Or am I off in my basic understanding?

So heads, mains, and tails are the same thing as fractions? First fraction=head, second fraction=main body, third fraction=tails?

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Theres plenty more than 3 fractions in your crude oil that’s why your deepest vac possible is crucial when separating each fraction. First come volatiles, then your heads are the nasty smelly stuff before main body thc that you are trying to separate your best to get that stank out. Your main body is your where you’ll find most of your thc. The tails are what’s in your crude oil that has a higher boiling point than thc. This is why you want to have solid vacuum depth the whole run so that you can distill almost all your desired cannabinoids from your main body before the color changes and the potency lowers because you are now boiling off something thats not thc at that higher temp.

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Thanks for adding some more context to this. So the deeper the vacuum gets the greater the separation of different fractions?

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No, the better your vacuum is the lower temps needed to distill the compound.Thermal degredation is the biggest enemy to short path distillation, heck even people cook their stirbars past the curi temp regularly.

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Ok, understood. The lower temp will decreases the vaporization point of the molecule. But does it create greater separation between different boiling points of molecules? Or does it make it tighter?

It can be used to break an azeotrope, to a small degree it better your seporation of certain compounds.When distilling cannabinoids I get better seporation with adding “theoretical plates”
to the aperatus in the form of packing.
check out this trippy saddle azeotrope graph.
https://goo.gl/images/WzX9YY

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Are you able to post the time lapse video of the color change on the key?

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