and THAT is my point…
I can test my ethanol. & know where I am. How do I achieve that with CDA12?
And CDA12 can contain toluene instead? No thanks.
Why would I use a solvent that I need to check in with a chemist to see if it’s still on point.
Because it’s cheaper?
But I get almost all of it back!
Ok so you are asking, “how do I find out how much heptane is in my solevent? How much water?”
You are assuming you always have 95% EtOH when using that alone and distilling.
Correct? And that is all?
1st: Thank you! I’m not a chemist, and will never claim to be.
I don’t simply assume 190 when I distill, I measure density at known temp using what the moonshiners would call a spirit gauge.
I certainly have to agree that after multiple passes over biomass there will be more than just ethanol in there, and I have been assuming those effects were negligible.
I have absolutely seen that my “tails”, pulled out in a rotovap rather than my still, are often not at 190.
I don’t combine those back, and use them for cleaning surfaces or spills. I should probably toss more of my heads than I do…
When doing Bucket Tek (Cold Ethanol Extraction on a Budget), one loses a lot of solvent, so co-distilled terpenes in the recovered solvent is compensated for by constant addition of fresh solvent.
Once one adds a centrifuge to regain more of the solvent (I’ve seen claims of 98% removal), it has been noted that the 190EtOH can acquire off odors. The simple fix there would seem to be to use vodka (activated charcoal) filters. use them every time. == same solvent every time.
I’m watching a facility spin up using the heptane denatured, and it baffles me.
There is a remote chance its the biomass.
Tried 190. worked great.
Tried fresh CDA12, worked great.
caveat: it was on different biomass.
my working hypothesis is that they picked up water from the biomass. probably early on when they hadn’t figured out how to get their solvent cold enough. by the time they had their temps under control they had water in all of their solvent. but my assumption is that there will always be some water pickup.
it seems to separate when chilled. (once water gets involved? )
which presumably makes drawing from tanks problematic.
If it’s just water removal, then yes, I’m an idiot and I can throw molecular sieves at the problem, but I’m concerned I’m not the only idiot out there, and it’s being pushed as a drop in replacement for 190 ethanol…without examining (advertising?) the process tweaks required.
I’m also not certain that water removal is all there is to it, it was stated above that heptane and ethanol do not form an azeotrope, these guys beg to differ
https://pubs.acs.org/doi/10.1021/ie8011769
this suggests the layering I’m seeing maybe the water/heptane azeotrope
or as said by someone not being sold the formulation as a drop in replacement
Lewis_Bronsted:
Better sourcing may be in order … some of the FDA approved blends seem less headachey, but it’s possible I’m ignorant and that product is optimized for this process off label.
it might be…but that is not my first response upon using it…seeing it used really, I’m just getting their BOCK installed…
S.D.A.-23A seems like a denatured formulation to consider. The denaturant in question should decrease fat solubility at cold temperatures, and it’s not toxic at all. I can’t say that 5% v/v is ideal, but combining ethanol and that simple ketone can likely be superior. Acetone doesn’t form an azeotropes with ethanol.
Thanks for catching that I missed the heptane ethanol azeotrope. I’d have avoided using it and finding out if I could lol it’s getting complex, and acetone/methanol aren’t too bad 
by which I mean as denaturants for ethanol.
Ethanol-heptane
Ethanol-water
Water-heptane
Water-lots of terpenes one by one
Ethanol-different terpenes
Is that all? Lol
190 is simple, and can be dried with sieves if needed, so it’s all what’s facile
I expect most won’t be using membranes for a hair longer than that
…and the extracted CBD crude tasted sweet. Presumably residual heptane…
Ya that would be scary 
Decarb it then taste
It’s all guessing until you get it tested
But that’s probably why most people don’t test on themselves first
“Here blaze up this wax that smells like sulfur”
Never know — could be how we got “hairless female primates”…that was great
That actually makes me slightly concerned about the unregulated hemp and cbd market
Probably lots of pesticide and shiT out there that isn’t going to be regulated to test.
Looks like FDA oversight is probably gonna be a great thing in the end.
Just wish we had more university studies but that time is here
@Lewis_Bronsted and @anon86230761 here are the wizards words on the subject I mentioned earlier.
I can make more sense of them now they have been written
Especially having done the suggested reading first.
Well end of story is stick with etoh.
I was looking to beat the energy requirements of refrigeration — not gonna happen until membrane tech.
Stick to safety I guess 
I do think liquid nitrogen freezing tunnels however would Be a brilliant addition to the arsenal vs cryo freezing the bio for extraction
Looks like you need a fed alcohol tax stamp for that as it’s “specially denatured” if you have that licensing might as well get cheap 190
I don’t know anything about the tax stamp but it seems specially denatured alcohols do cost more - pretty close to that of ethanol as you say, and that the completely denatured alcohols all have troublesome azeotropes. Distilling off the azeotropes first before use would be advised - but is that even legal? For the record ethanol laws are not my specialty… the SDAs are used for food and drug applications, so they are definitely indicated, however so is food grade ethanol, lol.
I’m going to look at this more, it’s fascinating, and I’ll share my findings if there are any.
ATF mafia. As far as I know, it’s all about potable or not. Apparently, you can get a tax credit or variance or whatever you wanna call that…exemption if you can prove or provide it is not being used for drinking.
Now that hemp is legal, game is changed.
I also will post something if I find that answer and how to file and the steps etc
That would be very useful to all and likely much safer with more pure ethanol use especially for the people that don’t get tested
From SA:
“To purchase Specially Denatured Alcohol, customers must possess an Industrial Alcohol User Permit from the Alcohol and Tobacco Tax and Trade Bureau (TTB).
• Permit must have customer signature and date of submission to Sigma-Aldrich in addition to the original signature and date.
• Permit must have word, “copy” handwritten or stamped.
• Permit number must contain correct state or US designation matching ship-to address.
• Permit address must match ship-to-address in Sigma-Aldrich system.
• Permit only needs to be provided on first order to sigma-xxx@sial.com.
• All orders require that a PO with the statement, “valid permit #####” be submitted to sigma-xxx@sial.com.”
I have a friend who has to have this permit to grow hemp etc in his local jurisdiction, I still am not super clear on it all.
