Acidification of Ethanol During Extraction

Ok so I have been doing a LOT of extraction using etOH over the last year and have recently ran into a potential issue of having the ethanol used to extract the biomass start to acidify over time. I saw a similar issue with a company I consulted for a few years ago. They could not run a batch without isomerization which consistency resulted in low potency scores and them getting publicly called out, a lot of money wasted and eventually they went under even after identifying and fixing the problem. The underlying issue ended up being that all the plant matter they brought in was stuff that had previously undergone hydrocarbon extraction and subsequently became acidic. Keep in mind that a number of other notable people had been brought in to try and solve this issue by the time I arrived.

Ok so I currently receive biomass from all sorts of farms, really runs the gamut. I have always been generally aware of the PHs at all points of my processes but recently began noticing very low PH during the initial extraction. Thus far I have been able to correct the PH using simple methods like filtering over neutral silica but Im wondering if anyone else has encountered this issue and also what some more aggressive solves for this problem might be. Correcting with sodium hydroxide or some other strong base doesn’t seem like the first best idea…


would also like to know of techniques to adjust ph of reclaimed etoh!

you can neutralize any solution by doing a regular old brine wash with neutral h2o


Definitely toss the ethanol tho

Talk to @Shadownaught, he carries some high PH carbon you might be able to try as a filtering aid.

My understanding is that your ethanol is mixing with water and at best is returning to the concentration of the ethanol water azeotrope. That solution can become more acidic and more laden with water over time, both of these things are problematic. The solutions for acidity wont solve the other problem and rotovaps wont help.

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I wonder if it’s coming from the air or rain, could moisture in the air be acidic? We do have acid rain. Does acid rain change the ph of your material if its outdoor? Idk just an outside the box thought.

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Ethanol will definitely absorb water out of the air. Especially if the ethanol is cold post extraction. I’m not sure how quickly. But the main way it gets in is when an extraction is performed moisture in the extractable material gets in. The water mixes with the ethanol and just has no way to leave the process. Ethanol recovery is really ethanol solution recovery. So anyways your solution gets more and more aqueous (polar) and can better pick up acids and other things.

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Why toss it? Jesus what a waste. It’s so easy to adjust ph


I run all of my ethanol through a column every few days to reproof and then push it all through a carbon filter to strip the terpenes and other stuff that carries over through the column. It comes out perfect every time.

It’s running right now actually.


Nice setup. Out of curiosity,
What % (give or take 30%) of the ethanol solution that you start with do you end up collecting at the end?

Its more than just acidity, imo, over time and through multiple redistillations youre going to have more and more contaminates, and ive noticed ethanol loosing a lot of its prime qualities. idk if its terpene contamination, actual reactive by products, or what, but at a certain point using a good supply of new fresh solvent should be inherant in any extraction business plan


What a fancy hp clamp

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Right- but no.

Once I get my SRI GC I will show you definitive proof that my solvent comes out clean from my remediation process- fractional distillation coupled with ac and ph filtration will leave me with the same product you purchase- pure ethanol.

@SummerSRI I can use the 310 to test ethanol for residual contaminants right? I mean it’s a gas chromo that’s what they’re designed to do.


I start at 40ish - even though it’s oil jacketed and about as safe as they come in terms of fire hazard I like to play it safe and not build potential explosion risks. Any higher than 45 and you’re starting to push into the danger zone.

I’m recovering 1.5-2gal per hour at azeotrope and I’ve never actually run it long enough to exhaust it- I just reload it with my spent alcohol that is recently carbon filtered (kill two birds with one stone and build my ac cakes this way) and then when it comes out I pass it through a carbon filter again and pump it through a column packed with mol sieves to make it nice and consistent.


i mean, SRI is the retarded red headed step child of the cannabis analytical scene, but ok, i dont really care. I will always advise my clients to regularly use clean solvent. Im not saying its impossible, im saying that you need more than some carbon and ph control, and that its not worth it. if youre doing small batches and need to make every last bit count, then maybe, but when we already go through 600 gallons daily, ive got bigger fish to fry


Like I said… it’s more than carbon and ph control- the most important step is fractional distillation, the filtration is there to take care of the volatiles that co-distill with the ethanol.

We also aren’t talking about cannabis analysis in this moment, we’re talking analysis of volatiles which codistill with ethanol and a GC is highly suited for that task.

Have you ever heard of a patent still or Coffey still? They are run continuously. 600 gal per day you’re telling your clients to toss out because you don’t understand distillation? Shame.


A continuous feed column still of that throughout would pay for itself within a month at that rate. I guess go you for supporting American biofuels that’s fantastic but you’re tossing a ton of money.

You would actually want their GNS skid but this is an example of an easy turnkey system that is commonly available and should be very affordable for folks running large jobs

@Psilisophical That’s cute. All 4 of Hugh’s children have different tints/shades of red hair! Did you know cannabis/hemp is about 5% of SRI’s business? The rest being green house gas, universities, landmines, etc.? Naturally, it’s been simple as f#÷k to measure cannabis…because GC measures hydrocarbons, and well bruddah, cannabis is loaded with hydrocarbons. SRI is proudly made in the USA. And damn those fine aluminum lids…