I don’t use heptane for winterization. I use my etoh for other things and don’t want to mix it with anything. I distill mixed solvents, but they don’t go back to the can of Virgin solvent afterword. If a process calls for solvent graidients, I’ll keep the recycled stuff to reuse for specifically that process.
4 Likes
That makes good sense.
I’m not winterizing. I’m extracting with it. not quite closed loop, but trying to recover and reuse the solvent as efficiently as possible. Adding a CUP to improve that.
The heptane example demonstrates that the solvent recovered in the rotovap can be quite different from the bulk solvent recovered via my 26gal still. I had been considering how to deal with that ,even though proof/terpene profile was likely the biggest difference based on my current SOP.
Wouldn’t dream of dropping any of this back into the virgin solvent container, but my working solvent is pretty much every drop that I can recapture.
Other than stripping the heptane out up front, I can’t see any good way of maintaining a “standard” ethanol to heptane ratio using my current methodology.
open to suggestions.
1 Like
I do bulk etoh as well, for that it is easier to make an inline mol seive filter. It won’t pick up your solvents, but will readily scavenge h20. Get series of sanatary spools, fill them up with freshly baked 3a seives. I use it as inline filter for the incoming etoh before it hits the counterflow heat exchanger. Blow them dry with nitrogen After you are finished. Pour them in big ass lasagna pans you get from the local restaurant supply. I let them sit in a fume hood with heat lamps on them overnight. I bake them in the morning, 400f for 2-3 hrs. Be very diligent about drying seives with residual etoh, boom in da oven!
2 Likes
U mean iso is 800 a barrel
$800 a barrel is approx price on heptane denatured ethanol. based on link to 710. Assuming @Shadownaught’s price is in the same ballpark.
$3300 is for 190 proof organic cane sugar ethanol from organicalcohol.com
Ok I see we been paying 800 for iso obv we need to switch and use that
Our heptane denatured is cheaper than that before shipping. A 270 gallon tote is cheaper than a barrel of tax paid ethanol.
2 Likes
Thank you very much for the reply. Just so i understand correctly, i can reclaim both solvents in the roto by increasing the temp or i could run the roto to separate the etho first leaving the 10l half full of heptane to then separately roto that out of i so wished?
Sure, I can strip the water out of my recovered ethanol with molecular sieves if I want 200 proof, rather than 190, but according to @Photon_noir, I actually want exactly that much water in my liquor.
Which of course means the solvent I’m getting back from my rotovap, which is almost certainly higher in water, should absolutely be properly refined before going back into circulation.
So I might want to hit you up on a still build too… 
1 Like
Ok! I can get 4" process pipe, and condensers!
The problem with ethanol for me is expense really and inconvenience. However there is a consideration I will suggest.
In my state as far as I know THC in a non potable liquid like isopropyl alcohol is not considered a usable drug nor is it regulated if it is dissolved in iso. THC in ethanol is considered a potable product of course and then there are ever changing regulations on number of ounces in possession and so forth.
From a marijuanna regulatory point of view isopropyl alcohol is much easier to comply with law than ethanol might be. One ounce of crude in one gallon of iso is not illegal to possess Oregon as far as I know. One ounce of crude in one gallon of ethanol is punishable by prison without the license to have that much as far as I read the law. It goes by number of ounces.
3 Likes
Huh, what if you had to explain that to leo! I don’t think they would understand! Wait officer! That’s iso! Not etoh! I swear I denatured that thc!
5 Likes
One early experiment I did was disolve extract in iso in a sep funnel. I very slowly over an hour or so kept adding tiny amounts of water. I was super gentle adding so as not to stir it up. I added the water to the sides of the funnel to keep it gentle.
Eventually the extract rolled out of solution like a brown gummy 
. However it did not come out of solution selectively except for some water white left behind. I tried two or three variations on the scheme but nothing really productive was accomplished for my purposes.
It may be different for ethanol but would be simple to test. The water must be added just a few milliliters at a time carefully to avoid mixing much. Once an emulsion forms it sort of wrecks it and gets messy.
Water up to the level of the azeotrope (about 4.5% by weight in ethanol) is ideal for all cannabis resin solvent applications, from extraction to Winterization. Yes, you can distill through a column of mole-sieve or even a chunky desiccant salt like non-indicating dri-rite or anhydrous sodium sulfate (chunks, not powder) to dry your ethanol. However, an easier way to improve your proof without overdoing it is to simply use ceramic rachig rings or saddles as column packing material. This works in any still with a column, and can even produce 200 proof if you are careful… so be less careful and make 190 or just over, then add distilled water back with stirring in a bucket with a hygrometer and thermometer for temperature correction of the hygrometer reading. Easy peasy! 
4 Likes
Hey everyone,
Lots of great info here, but looking to recap on original subject:
Seems like etoh/h2o aezeotrope is definitely superior to iso, especially when colder than -45C. Is it also superior for room temp extractions?
Isopropyl will not exhibit the same selectivity at -45C, correct?
And finally,
The etoh/heptane mixture, is this an adequate replacement for aezeotropic ethanol for cryogenic extractions?
Thanks!
I get it for $2200 deliver 190 food grade and organic
Im a new member, and a pretty basic chemist at best(biologist by profession). I’ve been using a dry-ice iso setup at various temps under the assumption it will carry less chlorophyll in the process(originally I was doing quick iso and only recently switched to dry ice), and would very much like to also hear if ethanol is superior to iso at very cold temps, and also whether I should switch to 95 rather than abs.
Also one last question, I have been concerned about adding dry ice directly to the solvent, as it tends to dissolve and change polarity/pH. Is that an issue, or does it not really matter?
are you recovering your solvent?
I made the switch to Ethanol from Isopropanol slightly before I had solvent recovery established. It was a huge relief not to have to deal with the stench of boiling Iso. Solvent recovery followed very quickly, to ameliorate the 5x jump in solvent cost per gallon. So win then win
If you’re using 200proof, and recovering it, you’ll need a way get from 190 back to 200. Or not, because scuttle-butt around here says 190 works as well or better.
As a Biologist, you might appreciate my logic on the safety of Ethanol…
We’ve been dealing with ethanol in our diets for some 2million years, since we came down from the trees and started getting our fruit off the floor. we’ve been selecting for tolerance to this stuff essentially forever. If your genetics don’t allow for ethanol metabolism, and mine do, whose genes get passed along? How about your mate. you’re both passed out. I’m not…
2 Likes