Overfilling SPD

I consistently work with a SPD, making both CBD distillate and THC distillate, but the company I work for uses an SOP that varies from what I usually see, specifically with how far to fill your boiling flask. We on average fill our 5L boiling flask with around 4500-5000g of crude. We have done smaller runs, and I have never really noticed a difference. I was curious if someone here knew why most places recommend only filling to halfway. Thanks.

If You get a bump
And crude go s treu the head all work is in vaign

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Never had that problem, and I make at least 5 kilos a week, and have been for over a year.

You are filling a unit of volume by a measurement of a mass. Is the density of your material similar to the density of water. In other words, is about 5kg of material = 5 liters of material?

In chemistry we usually run our reactions and distillations with about half full reaction flasks. Therefore, 5 liter flask is filled with roughly 2500ml of material. The unfilled space is generally referred to as head space and for distillation should help with seperation of your compounds.


You’ve never had to deal with material starting to muffin in the BF?? Companies tell you to fill 50% capacity because of the muffin that occurs during first pass and bump from aggressive boiling of volatile fractions during first pass.


If you go too much over 60% full your run times will greatly lengthen, fractions can be muddled, and the bumps are much less forgiving


how are your potencies? which fractions are you keeping (just cannabinoids?)

if you’re not having problems with bumping, then the only real issue would be lack of head space for the vapor phase separation you’re aiming for.

if you’re hitting your target potency, then I see little need to change things up just because “everybody else is doing it”.

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Well, when it happens It will certianly get your attention… like a rotavap boiling over…:weary:


I never go above half the volume of the boiling flask. I have no idea how you are not going Mount Vesuvius with a 5l filled to the neck. Or how your are managing good separation with the top of the crude being so close to the head. Or how you are heating that much crude efficiently. If you are managing all these things then you need to let us in on your sorcery because something magical is happening.


Also, where is your thermocouple? Are you running it outside the flask or are you putting it in the oil and filling past the adapter?


If youre able to devolitilize in a reactor or something, then you could feed that into into your spd with no fear of a bump or fraction smears. but at that rate youd be better to trickle feed into an empty flask

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There no head room for the nasties to escape and if you were to add the times filling 2/3 would be faster than all the way. Just my input unless it’s second pass done right then you can max it out

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Well we do decarb before placing the crude into the BF, which seems to help immensely with initial muffin. Also, we are still getting very potent distillate, around 93% THC, with 98-99% total cannabinoids, which is the only fraction we keep. Our run times are less than if we separated it into two runs. I am thinking we may be lucky as we are doing this at altitude (around 5000 feet) so our bumps are less bad.


99% spd?

this always bugs me, not sure why. i always see people posting weights when we are in a volumetric discussion lol.

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