The lower the temp is, the higher the recovery is. 
Not true
How much you can recover is determined by impurities
An 80% cbd distillate will only be able to crash out 60% of the cbd
When your impurity % = the remaining cbd % you won’t be able to crash any more out
This is why on the second crash you dont need cold to crash as its such a high impurity that it wants to crystallize
I’ve tested this, I did a recrash on a batch of cbg one at room temp one in the freezer
They yielded the same amount of cbg
We tried multiple solvents. We primarily use heptane in our processing but we were not successful with it on CBG and found that ethanol worked much better . With heptane we were only getting about 40-45% efficiency but moved up into the high 90+ percentile with ethanol.
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Were talking about crashing after extraction
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This not really about the amount of impurities (it plays a a secondary role by acting as diluent), this is basically about the solubility of the compound you’d like to crash. At saturation point, any excess coumpound crystalyze. It s more because the solvent does not want it, that the compound wanting to crystalyse. The better you control the rate of crystalization, and the larger the xtal will get.
And solubilty depend on temperature. It generally decreases as a function of temperature. I tested this in hexane, comparing -30 and room temp. Solubilty of cbg drops by 30-40%. I’m pretty sure this is similar in heptane.
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Just to confirm you had mentioned that hexane is only 10% less efficient than ethanol at room temp correct?
I’m needing to extract some more CBG and out of ethanol and would rather use hexane instead anyways.
Very interesting the drastic difference of extracting with hexane vs heptane considering they are very similar.
Doc is talking about crashing crystals from an existing extract. Isoguy is talking about initial extraction two posts above.
I was referring to the first post he made in the thread about comapirson of extraction efficiency at room temp with the different solvents:
To be clear I’m looking to wash CBG biomass with hexane instead of heptane and hoping I’m interpreting this correct that hexane is only 10% less efficient at room temp.
Youre incorrect
Why does pure isolate that you melt crash on itself within days without solvent?
Has nothing to do with solubility when the purity is high enough
Like I said if you have a pure enough product without anything to inhibit crystal growth the crystal’s will form regardless of solubility as they’re attracted to each other
Do the above experiment that I mentioned and see for yourself
Purity is the main factor in crashing yields.
If you have disty that’s 80% cbd and one that’s 90% and you crash them the same the one with 90 will give you a better yield everytime, regardless of what temp you crash them at
Theres only so much cbd that you can crash at any given time, once you hit that point you’re not going to get a better yield by dropping the temp more
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The answer is a little of both. Impurities act as crystallization inhibitors, and when they go down crystallization efficiency goes up dramatically. At the same time obviously the temperature has to be low enough for the solubility to decrease. After all have you ever seen CBD crystalize in hot refluxing solvent?
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If you take that hot reflux and let it sit at room temp or throw it in the freezer you’ll get the same yield if you give it enough time
Dropping solubility causes crystal’s to form faster and usually with more impurities
You can get a purer better crystal structure if you do not force them to crash and let them do their thing
Right. Now why do you need to take that refluxing solvent and let it cool to room temperature? To lower the solubility.
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Theres a certain energy requirement needed to break the crystal structure, if youre below that requirement crystal’s will form
If you’re above it they won’t
They will only form up to the solubility limit. In the particular application we’re looking at here though, it isn’t making a difference because the solubilities at room temp and at -20 are very close.
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Melted isolate will crash on its own with no solvent
Its an energy requirement more then a solubility requirement
This is why acidity promotes crystallization
Think magnets
You can take isolate and put it in heptane, it won’t dissolve without heat
On the opposite if you take melted isolate and pour it into that same heptane it’ll dissolve
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Well, this is ALWAYS about “energy”, dealing with physico-chemical processes.
It seems that you are a bit confused with thermodynamic concepts.
In those experiments you are dealing with, did you eventually produce some mass balance calculations to support your claims ?
Dissolution is, in general (there are exceptions) an endothermic process. It means that it consumes heat. The more heat is brought by the system, the more this occurs. Now think in the reverse way…
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There are two main ways we can envision for such inhibithion process. Either the impurities coat the crystal surfaces, or these act as co-solvents and/or dispersants. Regarding how people successfuly crash crude extract, and even how this can happen on itself over extended periods of time, I’d say that cosolvent inhibition is the most likely explanation.
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Yes, like I said above try taking 1st crash isolate and doing a second crash at room temp and in the freezer
The yields will be the same
Solubility doesn’t explain why isolate crashes on itself with no solvent
Dude that’s because isolate, by itself, is not a solution. Solubility has nothing to do with it. You are comparing two completely different things. A phase transition is not crystals crashing out of solution.
A more relevant comparison would be dissolve distillate in hexane 1:2. Then separate into two portions, leave one sealed in the freezer and the other sealed at room temp. As it so happens i just did this recently, and have pictures. Way less isolate crashed at room temperature even after weeks of sitting.
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Phase transition has nothing to do with what were talking about.
Is frozen distillate a crystal?
No
Crystal’s have defined structures
Why can you have melted isolate that’s liquid at a certain temp and also isolate that’s solid at that same temp?
They both have the same amount of energy at the same temp yet ones liquid and ones a solid.
Something that’s a crystal in its natural form wants to return to that form and will do so as long as there aren’t too many impurities and its energy isn’t too high to keep the crystal’s from forming
Atoms vibrate based on how much energy they have. If that vibration is too great crystal’s won’t be able to form because they’re bouncing off each other too much
Heat up some isolate and distillate and watch which one crystallizes faster.
It has nothing to do with solubility it has to do with purity.
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