Short Path Distillation for Transparent Concentrates




Right to left: 1x, 2x, 3x distilled

There’s been a lot of interest in turning less than appealing concentrates into a quality product. Recently we were loaned a Kugelrorh and tasked with standardizing a method to produce a consistent product.

The basic work flow prior to distillation is very important. There are two steps that must be completed prior to short path; winterization and decarboxylation.

Dissolve the extract in 190-200 proof ethanol at a 10:1 to 15:1 ratio depending on particulate load. Chill to at least -40c but ideally -80c for 24 hrs. Filter in a buchner funnel using coffee filters on top of 2um fast flow filter paper. Distill alcohol in a still or rotovap.

Quick winterization:

Follow as above, except place dry ice directly into the ethanol solution and maintain for 2 hrs at -80C then filter immediately.

Heat oil to 121c on a heated stir plate until all of the tiny bubbles are gone. If you get impatient and remove too early you’ll likely have issues during the following steps.

Short Path distillation equipment:

A simple boiling flask with Vigreux condenser can be used to produce distillate. This is the most economical option but, also has the lowest yeilds.

A good example of can be found on Google or here.

The next step up in production efficiency is the Kugelrorh thin film distillation apparatus. Currently there are 3 companies manufacturing these; Sigma Aldrich, Buchii and Jkem. kugelrohr


The next step up in production is the wiped film evaporation. A good example would be a Pope or similar apparatus.


A similar but, larger unit that uses a rolled film rather than a wiped film would be the Terp Trommel.



There are 3 distinct fractions in this procedure; 1) the light volatile’s that have boiling points below or slightly overlapping 2) the Cannabinoid’s and 3) non volatile’s.

Dual fraction systems, those that separate one fraction at a time, temperature is raised gradually to remove the volatile fractions in order of their respective boiling points. Generally the lowers are removed below 185-195C depending on level of vacuum and film thickness. The Cannabinoids are separated next up to 260C in some devices and the black non volatile fraction is discarded.

Three fraction systems, such as the Terp Trommel, separate all three fractions in a single distillation step. Accomplishing this feat of engineering requires close attention to thermodynamics and residence times to separate the volatile’s from non volatile’s in continuous operation.

Post process:

Distillates can be re-distilled several times for improved color and stability. Mono-terpenes or vape ready flavorings can be added for improved flavor and viscosity for vape pens. Distillates in the raw can be vaporized or put into edible products for improved flavor over RSO products.


Pharmer Joe


75 responses to this post.

  1. Posted by redturtle984 on August 24, 2016 at 4:32 AM

    A supplier friend brought by some black goo lolz and wanted to see what could be done. Waxes were removed by disolving in rubbing alcohol, adding a small amount of alumina to the solution, then freezing. Out of the freezer into a centrifuge at 4000 rpm for 15 min, then into a clean tube and repeat the freezer cycle until all waxes were removed.

    A test run on the dewaxed portion confirmed that pure short path was impractical with my gear on this particular sample, so I decided to use the short path apparatus to co-distill the extract with water. Co-distillation solved the problem but a new question popped up; why did this batch require a head temp well above the nominal co-distillation temperature?

    The batch co-distilled nicely and the green goo left in the boiling flask will be flushed and the refined product run through a second time after all glassware has been hand washed and run through th washing machine. Co-distillation does not produce the hideous smell that regula distillation does but the fresh pine scent in the water is enough fresh pine scent for six neighborhoods lol! Now my drains smell like pine trees 🙈


  2. Posted by redturtle984 on August 11, 2016 at 8:51 AM

    Here is a vid my cool iPad app spit out from pictures.

    I have found that covering extract in Aluminum Oxide then running that at high temp and very low vacuum in a cryogenic sublimator will utterly deoderize the extract. It removes or converts all pinene which collects abundantly on the cold finger. This is a sublimator but used as a modified short path to fraction just the first fraction. The other parts of the mix can be recovered selectively from the Alimuna by timing the soak of the extract covered alumina in a fairly polar solvant and/or adjusting solvent polarity to extract the desired fraction from the alumina.

    The oil becomes blood red and is evaporated of the solvent then vacuum purged and boiled in H2O. Boiling it removes a lighter than wat portion of the oil, a very small part, and the rest is dewaxed and enjoyed to great effect. I suspect I am isomerizing nut not oxidizing a number of substances and it becomes a very pleasant flavor. Very simple setup but only for personal use quantities as can be seen in the video.

    I do not use flower but theorize that bud brought up to high temp in a vacuum like the sublimator will also release the pinene (very nasty smell) without destroying the thc.



    • Posted by redturtle984 on August 11, 2016 at 8:59 AM

      I have petitioned the Olympic Committee to consider Separation Alchemy as an Olympic Sport! Please sign the petition.


  3. Posted by redturtle984 on July 26, 2016 at 4:42 PM

    A short vid showing a sublimatoe being used as a short path distillation. It turns extract into clear which is wiped from the cold finger.


    • Posted by redturtle984 on July 27, 2016 at 2:23 AM

      The extract wiped from the bottom of the cold finger is clear light yellow thc oil. I have not tested any in a lab and likely will not as my home hobby lab is suitable for me. I have a column chromatography tube ($35 at Ctech glass) and have used an airbrush air pump to assist (rudimentary flash chromatography) and am using aluminum oxide between 100-400 grit also for seperation and I am setting up the unit to test the purity but it will not be congruent with certified results so would be meaningless comparatively.

      I will caution about my video using the Chemglass Sublimator ($350 from Amazon). The dark oily portion of the extract left in the bottom on my first run had visually ceased producing vapor and was a fraction of the beginning gram. It looked like vaporizer residue, nearly black to black but under vacuum still seemed like it was all done.

      Until I released the vacuum and broke the seal of the sublimator….wow! The residue on the cold finger is just fine, but once atmosphere hit that hot oil – instant nasty, make you want to vomit smokey fume filled the vessel bottom vessel.

      I suspect the smoky vapor was volitile from the odor. Not necessarily a safety issue, but next time I am going to use my infrared camera that plugs into my iPad to confirm lower temps before releasing vacuum.

      It takes less than 30 min start to finish to produce clear from raw extract using this device. One vacuum pump, one sublimator, Nalgene vacuum hose ($17 per foot on Amazon), a hot pad, stands, and ice water, and one iPad to document all this foolishness is all it takes. I do not grow but my hunch is that any extract from iso, hexane, or any other suitable source and not just supercritical fluid extract could easily be purified this way.


      • For safety, one should use an oil bath (a deep frier would work) as a heating source instead of setting the sublimation chamber directly on a hot surface as is shown in the video. By setting the chamber directly on a hot surface, one risks uneven heating which can crack the chamber. Also, the oil bath will heat the sides of the chamber making the process more efficient.

        Finally, let the chamber cool to room temperature before releasing the vacuum; this should help reduce/eliminate the smoke.


        • Posted by redturtle984 on July 27, 2016 at 7:34 AM

          Copy and paste from the manufacturers website, the specs on the unit are specific and the instructions were followed per specification. Please contact the manufacturer with your concerns Dr. Wahl. I am gonna vape some of the clear now lolz.

          Two-piece grease-free sublimer with a flat bottom to enable heating on a hot plate stirrer. Condenser has a large top opening for use with dry ice / acetone or liquid nitrogen. Connection between the flask and condenser is made with a flat o-ring joint permitting parts to be gently separated for maximum product recovery. The capacity listed is that below the bottom of the cold finger. Vacuum control is provided by a 0-8mm grease-free Chem-Cap® valve. Complete apparatus consists of the condenser, flask, Viton o-ring and horseshoe clamp.


          • Generally, glassware is heated in oil, sand or other types of baths or heating blocks which ensure uniforming heating both to improve heating efficiency and to avoid heating induced stress cracks (this is a major problem with flat-bottom flasks, like ChemGlass CG-1502). That said some glassware is designed to set directly on a hotplate: beakers and Erlenmeyer flasks.

            All that aside, you well get better performance if you use an oil bath, especially if you work with more than a gram of material (none of the solids will form on the other wall of the chamber). For the scale you are doing, it probably doesn’t matter all that much.

          • Posted by redturtle984 on August 4, 2016 at 8:43 AM

            Kudos to you Dr. Walz for the suggestion of the crock pot. I filled the bottom with sand so the sublimator can be positioned easily the n fill the rest with fractioned coconut oil from Amazon. the label says it is good up to 350F for cooking and my last run purifying extract was substantially below that.

            The main advantage I have for,personal use is small sample size – just a few grams or so. The sublimator vacuum gets very low, pegging the gauge at the 30″ mark (analog gauge). Obviously the sublimator is like a vacuum chamber all by itself but one that is heated on one side and cooled on the other. I think the cooling of half of the vessel contributes to a great vacuum. The first fraction off smells just like pine needles being crushed. Without that substance, pinene, in the extract I am vaping now without resperatory burn even without dewaxing.

            The extract, referred to as “Hulk” has zero odor at room temp after process and is quiet odiferous before. Thank you again for the tip.

        • Posted by redturtle984 on July 27, 2016 at 10:25 AM

          My main problem during this lab really was I used completely unprocessed extract straight out of the package. Anytime raw extract is cooked it tends to pop and sputter. Dabber know this lolz even though their temps used are much higher. I have found this behavior in all purchased extracts so it is nominal.

          I have a process using iso that we previously discussed until the dog done died that stops this sputtering completely. I suspect that the sputtering is from hydrophilic substances present in a mostly hydrophobic mixture because the iso process I use removes most of the former plus the waxes.

          The sputtering in this lab popped a little up on the glass sides and cold finger. I am still pondering a mechanical solution as the iso wash is very involved comparitively. Maybe a lower temp as well. Vacuum gauge was pegged at 30 on the mechanical gauge and I am notoriously impatient so heat things quickly.

          Now I just have to wait until payday to afford the next sample lolz! Can you write a grant for me? 🤓


        • Posted by Edward Andre on July 27, 2016 at 8:18 PM

          hi,message is for Mr. Troy Wahl.hello sir i am ready to spend $500 and to sign NDA agreement ,how can can get in contact with you.thank you.


          • I can be reached via LinkedIn (I’m the only Troy Wahl in the Portland Area of Oregon). Just send me a PM and we can talk there.

        • Posted by redturtle984 on August 5, 2016 at 4:32 PM

          Another run done in the sublimator. Started 5g fresh extract, removed .5g clear pinene (pine scent). Sublimator tipped causes drip of pinene to fall out of boiling crucible. Activated carbon pellets are very hard and retain heat and absorb volitile organic compounds (VOC) like pinene nicely. Vape is chalky sweet, waxes left in, zero respiratory irritation and as potent as it gets. Started with “Hulk”. Temperature of oil/sand bath constant at 147C (296F)(421K) and the vacuum held constant at 30″ on the vacuum gauge. Clear condensate seen on finger is pinene.

          I estimate that 12% of this extract was alpha-pinene. MSDS for that recomends no inhalation or skin contact.


          • Posted by redturtle984 on August 5, 2016 at 4:40 PM

            I put activated carbon pellets into the oil cup on my dab rig and dab onto those. They really smooth out the vape plus make smoking it a good option for me.

        • Posted by redturtle984 on July 27, 2016 at 2:50 PM

          I just vapes some. Faint aftertaste of pinene . Same quantity of vape I normally dose with of this has produced a profiundly potent high and an unusual body rush. Very potent. yay. 😗❤️👌🏼


  4. Posted by dan on May 8, 2016 at 8:51 AM

    Hi, whats a good condenser temp to start with? I was also thinking about flushing the apperatus with nitrogen prior to pulling a vaccme on it. Do you think that this would minimize side reactions caused by oxidation? Aslo what is the purpose of decarboxilating prior to distalation? Is it so the cannaboid fraction will have a similar boiling point? Does it somehow make the tastes bad? Whats going on in there when thca is distilled?


    • I would need to know more about which system you are using to give you a temperature for your condenser.

      The purpose of decarboxylation prior to distillation is so that the solution doesn’t foam and bump during distillation.


      • Posted by dan on May 8, 2016 at 8:00 PM

        Hi, going to be using a short path distalation apperatus with a small vigerux section, the condenser is about 175mm. The glassware is 24/40 and I plan to use a 1000ml boiling flask with 3 100ml receiving flasks on a cow.I have a welch high vaccume pump and savant refrigerated cold trap.Im heating it in a pid controlled oil bath/ mag stirrer. Any advice?


    • The answer to condenser temp is both easy and complex: The easy part: it needs to be warm enough so that the distillate does not solidify but not so warm that it does not condense. What makes this issue complex is that mixtures (common in extract distillations) melt at lower temperatures than pure compounds and that the distillate can dissolve small amounts of compounds that would otherwise be solid. For a distillate containing THC start around 75C, but you’ll need to experiment a bit as different set-ups will have different requirements (remember, the distillate has to remain warm enough to flow into your receiver and not just out of the condenser).

      Purging your equipment of oxygen prior to use (either for extractions or distillations) is a good as oxygen reacts with your product. The best way to do this is to close your equipment, evacuate it to less than 100 Torr (~ 1/8 atm), fill with nitrogen, and repeat twice. It is best to use a check-valved bubbler (such as a CG-4522 from ChemGlass) when supplying gas to sealed glassware so as not to over pressurize it. For solvent based extractions (other than butane or propane) using a continuous supply of nitrogen will help minimize oxygen. However, for distillations the nitrogen supply should be turned off unless one is doing a distillation at 1 atm and it is connected after the condenser (if it is connected at the stillpot it will screw-up the distillation).

      One can not distill the cannabinoid acids, attempting to do so will decarboxylate them. If you want to isolate them as pure compounds, contact me directly.


      • You can’t mechanically remove other oils from the extract.


        • I did not say anything about the methods one can use, just that it can be done. That said, you are correct, purely mechanical methods will not work.


        • Posted by redturtle984 on May 8, 2016 at 1:20 PM

          I am going to attempt to use my cryogenic sublimator to obtain pure. I washed the extract to nearly pure using mostly info from a patent on purifying citrus oil. The problem I see is that I cannot get all the higher boiling point terps out with just a wash described in thte patent. I even centrifuge, like the patent decribes.

          I took videos of it so I could analyse it but my main concern prior to doing a lab plan for the sublimation just how to go about it. My belief is that the temperature needed to get the stuff into gas will heat the terps and change them. I know what burnt terps/shatter tastes like and it is foul to me. So I am at an impasse as how to,procede. The first part in the patent worked magic. Pulled put waxes and undesirable terps to a great extent. End product nearly clear.

          Citrus oil seems to have about the same challenges involved with the pirification of it, and it seems to me after using the info that it works for raw marijuanna extrat also. I am at the last part requiring fractioning. I have evaporated off the binary solvent and the terps that it took with it, so now am to the distillation part using e cryo sublimer.

          Any input anyone has on set up cautions and safety considerations please feel free to input. I am planning the ice bath to be iso and dry ice because I can get it pretty easy. My mobility is limited so easy is good!

          What pitfalls does anyone see in the plan I outlined above for getting to pure?


      • I have a helium tank here at home that I use to fill balloons for kids in the neighborhood. Since I have this gas and I am just a hobbyist in this, can I ourge the system of ambient atmosphere with the helium in the same manner as described for nitrogen?


      • Posted by dan on May 9, 2016 at 4:58 AM

        I have been doing more research and ran across alot of people saying that their distillate has an unpleasant odor, is this a fraction present in the starting material or is it molecules being destroyed by heat? Also how would I prevent this?


    • As I recall the acid form of thc boils at 90 deg F lower than the converted Delta 9 form. Since than conversion takes time I think it would mean the boiling point would be plotted in an unpredictable curve. I think that a substance that slowly changes boiling point because of decarboxylation would through off a reflux unit, wouldnt it? I just got a cryogenic sublimator and plan to,try to sublimate thc crystals on it. I am planning to decarb the sample sully prior to,the test because I do not want to sublimate the acid form. Any suggestions or comments are welcome. I appreciqte this forum.


    • Posted by redturtle984 on May 9, 2016 at 8:38 AM

      There is more going on than simple fractioning. At very high temps limonine breaks down into isoprene I believe, and isoprene boils at about 140 C lower than limonine. I believe that in the moment limonine breaks down it boils out as isoprene. I allowed my extract to boil until refluxing on a beaker. It got black and nasty looking and the fume smelled bad. The next day I vaped some and it was perfect. Deep smooth vape hits, no hacking or choking followed by a very fun high. Highest potentcy.

      There is a taste that I can only describe as pleasantly toasted. Like carmelized sugar but not so sweet in the vape. Fruity. I am making more lolz. The beaker cooking the extract was on my stove top. I had the stove nearing med high and over 350 F when I put the thermometer down to cover the mix from popping a bit. It boild but got VERY hot before it did. I hope some of this helps. I am gonna vape some of this deep red to black but clear and stony sweetness now. Is that wrong?


      • While limonene can be oxidized, it is extremely difficult to decompose it into isoprene especially in the presence of oxygen. This is also true for the rest of the terpenes/terpenoids. The other issue one needs to consider is that heat and light (UV) can cause these compounds to polymerize.


        • Posted by redturtle984 on May 9, 2016 at 1:22 PM

          I lacked the right thermometer to test my boiling puddle so
          i am, not sure the temp but it got very hot. The fume was repulsive to inhale when I removed the lid, but a sit in the freezer overnight led to some of the most pristine vaping I have every done. The stuff is glass clear but dark amber, almost red.

          Dr. Wahl at what temperature, given that the mix of actual components is unknowable, do you believe the limonene and other terpine break down into more volitile components like isoprene? My stove top was set between med and high to get it to finally boil in that beaker enough that it was feluxing down the sides. I llaced a dish of glycol I keep in the freezer for a cold bath on top of the beaker as a cold lid to help it reflux.

          I recorded all the things on my iPad on video this last run. Using the info in the patent of citris oil purification I have made nearly clear product using just the simple binary solvent listed in that patent and centrifuging to remove the gunk. I discovered that a paper filter rated “slow” to catch fine particulate lets cloudy material (DNA?) right though and this can only be removed in a centrifuge. The VAST majority of the cloudy nature of extract is quickly removed when following the steps in that patent. The results prior to any heat application but a vacuum chamber treatment at 29.5″ of vacuum for 15 minutes were so,clear that I have to tip the beaker so it will run to see the yellow tint. I did not heat half the stash and it too is 10 out of 10 for potency, but still has a bit of that “mentholatum” type mediciney feel that the other half which was boiled doesnt.

          The other thing that might be affecting taste is a mystery substance that ALWAYS appears when I cook this stuff in the binary solvent used in the patent; it will start out clear, then long chains of white gunk slowly form in the clear liquid, They will appear enough to fill the dish, then after just a few minutes they begin to shrivel and turn black. They tend to drop out of solution then and fall to the bottom of the pot. Components like these are likely the cause of foul odors? What is it that rolls out of solution after filtering then shrivels up and turns black? I have a video that shows the form the shrivel the turn black.

          Thanks for letting me share. I am gonna vape some red now. I have the advantage of being my own test subject! I just have to wait until next payday for more testing material.

          Peace fom Oregon.


          • Pyrolytic cracking (breaking C-C bonds with heat) is typically done at over 300C (570F), several atmospheres of pressure and in the presence of catalysts. Remove the later two, and one will need much higher temperatures. Pyrolysis, however will not happen in the presence of oxygen.

            At this point, you’ve reached the end of my willingness to answer your questions without charging.

          • Posted by redturtle984 on May 9, 2016 at 10:46 PM

            no worries. I knew a professional lady in Memphis that reached that point in just a few minutes! You have been more than generous with your intellect. Thank you.

          • You know for about $500 of my time, a signed NDA, and some additional equipment (most of which can be had used on eBay), I can greatly improve your process and safety, while reducing the amount of experimenting you are doing and answer nearly all of your questions…

          • Posted by redturtle984 on May 10, 2016 at 7:45 AM

            That’s what she said too!!!

          • There is a reason for it: our experience and fees plus the cost of equipment, cost less than your experiments over the long run (actually the not so long run). BTW I live in Oregon, so part of my fee covers meeting you in Eugene.

      • Posted by dan on May 9, 2016 at 12:21 PM

        Did your first runs have any bad odor? I saw a youtube video of a guy discussing fractional distalation of canaboids, he talked about an odor that was unpleasent. He also talked about the odor being removed by allowing it to overshoot the condenser into the cold trap whilst still collecting the cannaboid it possible that this smell is degraded limonine? Because its boiling point is lower that the canaboids it could be possible that this is responsible for the odor?

        here is the video, the man isn’t very educated the way he talks, but I think there is some information to glean from it.


        • Posted by redturtle984 on May 9, 2016 at 2:30 PM

          Here is what dispensary extract looks like after the wash I talked about and after the vacuum chamber but before heating or attepting boiling. It is runny like molasses and the high is pristine.
          this is nearly pure medicine in this form but turns dark red to black when boiled as I mentioned above (this was the other half of my stash I did not boil but came out of the same stuff.


        • this guy is fucking awesome he has the right information, i can’t wait till the next one comes out


        • Posted by redturtle984 on July 29, 2016 at 5:27 AM

          The foul odor he speaks about is alpha pinene which is the main component of turpentine. It is repugnant to smell and is ine cause of espiratory irritation.


          • Posted by redturtle984 on July 29, 2016 at 5:29 AM

            I should add that alpha pinene is one of the only things in extract that is miscible at least partly in water. This is what the iso wash removes.

          • a-Pinene smells strongly of pine. It’s fairly pleasant, actually, if you like pine. That’s the main and virtually only fragrance note, and one of the most common and recognizable terpenes in cannabis. Pinene (alpha and beta) is also used in room fresheners and cleaning supplies. The foul smell you are getting may contain a-Pinene or its derivatives, but comparing your description to the large bottle of it that we have in our fridge, there is more to it than pinene.

          • Posted by redturtle984 on October 4, 2016 at 12:15 AM

            Try heating that stuff you have in a bottle Captain up to the temperatures needed for fractional distillation in the process shown and take a good whiff. After you barf, tell me again you want that odor in your cardboard pine tree dangling from the rear view mirror lolz.

            You have the stuff. Give it a try.

  5. Posted by D. Welch on April 19, 2016 at 4:54 PM

    Hello Skunkpharm,

    Just wanted to say thank you guys for everything you do. I work in a cannabis testing facility here in Colorado and I’m just curious if you have any potency testing results for these distillates. I’m sorry if I’ve missed this topic somewhere else, just came across this article in a quick search. Keep up the good work, I love this site!


    • Best place i know of to look at results is sc labs in california. They publish everything on their site. If you want baselines for any extract check it out.


      • Posted by redturtle984 on July 29, 2016 at 5:14 AM

        I must confess that the purest oil I have made at home is in the sublimator, but I have found that by itself it is not as pleasant to vape as the iso/water wash treatment I do. The clear yellow thc oil is best when added back into the red hash oil that I make.

        When blended with the red, the perceived potency is much higher than vaped on its own, but beyond that there is someing intangible for me vaping the clear versus the red oil blend. I am diagnosed with severe chronic PTSD. I have been trained through therapy to identify when my limbic system activates signalling an onset of PTSD symptoms. This means that my blood becomes flooded with the same things that everyone else blood gets flooded with when they are scared. Adrenalin and all the other things a body needs to engage in either fighting or running from the danger.

        I have a cabinet full of pharmacuticals that address aspects of this but they do not do all that well compared to thc oil I make. Without any doubt, vaping the clear does produce a high but it simply does not difuse PTSD symptoms like a blended oil does for me. Producing pure is pretty simple. Turn a glass funnel upside down over a small bowl of extract. Put a test tube on top upside down on the funnel down spout to cover.

        Then simmer the extract on low heat. The first thing the funnel catches is nasty nasty nasty, clear pinene. Yuck. I wipe and throw away. Then the mixture will begin smelling sweet, and begin collecting on the funnel. I blow a fan over the top. Wih patience anyone can capture clear this way. I bought an iPad app that makes videos out of photos and stuff and made this one creating clear red oil.

        My next vid will be showing the blending of clear back into the red.

        If you watch the video and pause it you can see the kind of temperatures I use to produce the red. When that thermometer slips past about 300 or so F and the mix settles down and starts climbing to 360, the red is done cooking. There are normally three temperature plataeus during the cook.

        Compared to clear the red is hands down a better med, but blended with clear? boy howdy is it potent stuff. Not a lab test per se but I use a great deal of extract, normally an ounce or so a month between use and the botched experiments lolz but after several years I can identify potency pretty close.


  6. While this is reasonable, more effective and efficient is chromatography. Even in it’s most basic form, chromatography allows one to separate the waxes and non-polar (perhaps better to say, least polar) compounds from the cannabinoids, and the cannabinoids from the black junk. In more advanced forms, chromatography allows one to separate each compound without heat, which causes chemical reactions and degradation of product.

    If you wish to know more, please contact me.


    • Posted by Mark Lee on April 1, 2016 at 8:16 PM

      I’d like to know more about the no-heat alternatives if you have some information you can share. Thanks!


    • Posted by redturtle984 on April 17, 2016 at 2:18 PM

      Is there anything regarding azeotropic distillation that you can share, Dr. Wahl?


      • Sure: an azeotrope is a where two or more compounds distill in a fixed ratio, commonly at a temperature less than the boiling point of the individual compounds, and thus behave as a single compound – distilling an azeotropic mixture will not separate the compounds. The ratio of compounds depends on pressure. A binary azeotrope maybe, in addition to changing pressure, be broken by adding a third compound, an entrainer, that forms an azeotrope with one of the other compounds so the the new azeotrope has a lower boiling point than the original azeotrope. For example:

        Water and isopropanol form an azeotrope at 1 atm. with a boiling point (bp) of 80.1C, and a mass ratio of 12.0 % water: 88.0% isopropanol. Water and benzene form an azeotrope at 1 atm., bp: 69.25C, mass ratio 8.95% water: 91.05% benzene. Isopropanol and benzene form an azeotrope at 1 atm., bp: 71.74 C, and a mass ratio of 33.7% isopropanol: 66.4% benzene. Thus benzene can be added to rubbing alcohol (the isopropanol-water azeotropic mixture) to separate water from isopropanol.

        Is there something else you wish to know?


        • I am a patient and suffer severe respiratory distress from standard dispensary extract. Do you believe there is a safe way to render the extract safer for me to use (so I do not hack and choke) by removing at least some, or possibly all, of the irritants from standard lab tested extracts by using the extract as an entrainer in an azeotropic distillation of that binary azeotrope thingy you mentioned? It occurs to me this may be possible?


          • Hi Dennis,

            Unfortunately for you, no (at least not with water and isopropanol). For two compounds to form an azeotrope they must have equal vapor pressures at a given temperature and pressure. Cannabinoids have almost zero vapor pressure between 20 C and 100 C at 1 atm. There might be azeotropes between water or isopropanol and some of the other compounds in cannabis oil, such as one of the lighter terpenes, but that would only allow you to remove that one compound. What you need is a different technique to isolate individual compounds.

            I would also suggest edibles. Unless you have no other way of taking the cannabis, why subject your lungs to any type of irritation?

          • Your response comfirms for me many things I believe to be true about big pharmacutical types. Thank you.

            Of all the binary azeotropes listed on Wikipedia why did your response focus on the obscure notion that “rubbing alcohol” was the basis of my question Doctor Troy Wahl?

            Thank you for your time. It is rare that somebody as smart as Alex Trebek, or any other game show host for that matter, would take the time to help educated an old Marine
            with service commected PTSD and a litany of ambulatory problems. Especially a doc from big pharmacutical. I can find no appropriate words to share with you that you took the time to respond the way you did.

            I hope your career path finds for you the place in our community you deserve Dr. Troy Wahl. I know I will remember this! Just remember to phrase all answers in the form of a question for Final Jeopardy lolz – it will keep everyone guessing!

            Be well citizen

          • I choose rubbing alcohol because it was something familiar to most readers. Truly, how effective and helpful would the example be if I used propionitrile and propyl ether instead?

            BTW just because azeotropic distillation is not an effective way to purify crude cannabis extracts, does not mean that distillation would does not work. My biggest peeve about using distillation, besides the very high energy cost, is that pesticides are extremely difficult to remove by distillation (a lot of pesticides have boiling points in the same range as the cannabinoids, but are in such low concentrations that they don’t form their own fraction).

          • azeotropic distillation is a chemical reaction doctor. The total energy cost to fractionalize iso from water is zero. I have done this many times without any heating or cooling and it does indeed work. Just dump some extract into some off the shelf rubbing alcohol doctor.

            I truly appreciate that you need to make a living, but I do not think there is much consulting money to be made with the simple washing of extract with rubbing alcohol. You used it as an excellent example, almost like you knew where I was going with it!

            Great minds think alike doctor. Obviously my opinion is different than yours. My opinion is based on personal observation and significant experience with a variety of tried methods to accomplish this, and without any question at all I have accomplished what you just posted cannot be accomplished. One of us is correct, and one of us isnt. You have posted a lot of true facts, sure, but in the country we know for certain which end of the bull the hay goes into.

            Put simply doctor, I am of the opinion that the information you have provided is not accurate and I am of the opinion that your comments are not credible when it comes to removing irritants from dispensary extract in Oregon.

          • No, azeotropic distillation is not a chemical reaction (no chemical bonds are formed nor broken), it is a physical process. Distillation in any form, requires energy to vaporize compounds. It also requires energy to separate compounds, as it is an anti-enthropic action.

            When you add rubbing alcohol to a crude extract and then get two separate layers you are not distilling anything, you are getting a phase separation which is a different physical process from distillation (the technical name for this is solvent-solvent extraction). That phase separation happens, in this case, due to the fact that isopropanol is soluble in many hyrdophobic (water hating) chemicals found in cannabis extracts. At the same time as the isopropanol is dissolving into the cannabis extract, some of the more hydrophilic (water loving) compounds in the cannabis extract are dissolving into the water (which still contains some isopropanol).

            Unfortunately, many of your “true” facts actually demonstrate that “you do not know what you do not know.”

            As for knowing where you are going, of course I do… we’ve been having this conversation for two days where your posts about your methodology keep getting taken down, I suspect, because it is dangerous and the site owners do not wish to be held liable for injuries or deaths that might result. To be fair, the use of proper distillation techniques to remove the isopropanol from the product would make it much safer, as would analyzing the product for residual isopropanol content. Yes, solvent-solvent extractions can remove many undesirable compounds from a crude cannabis oil, but they also remove some of the desired compounds as well. For small scale applications the looses are not worth worrying about, however they become significant for an extraction business.

            Finally, how dare you criticize me for trying to make a living off knowledge I’ve acquired over more than 20 years. Do you suggest a carpenter, a mechanic, a plumber, a doctor or lawyer is wrong to charge for their services? So why do you think you, or the rest of the cannabis industry, have a right to any chemist’s expertise for free?

          • Posted by redturtle984 on April 18, 2016 at 11:21 AM

            please accept my heart felt apologies for speaking rudely to the doc. My only real hope was to grab attention of others and alert them to a method that works well. I am glad that you have seen instructions regarding how I do this because I see an innovative spirit on your sight and I hope your crew takes it up and ru s with it.

            Without question, you could easily advance the idea into a refined technique if you elect to.

            Thank you again for the sight and please forgive an old man. I get fired up when I see this kind of thing going on. I will do my utmost to stop posting personal observations about other users of your site.


            Sent from my iPad


  7. Posted by The Larry on April 1, 2016 at 10:02 AM

    Speaking of vape pens and short path distillation, doesn’t decarboxylation give the oil a roasted almost nutty flavor, and if so, is it good to sacrifice flavor for color? What is the process for decarbing that won’t have the oil going nuts, or is the nutty flavor here to stay? Can that taste be processed out of the oil? What’s the word? Big THANKS.


    • The nutty flavor you are referring to is the result of side reactions. To minimize this, it is best to separate the acids from the rest of the cannabinoids before heating the acids to decarboxylate them.

      If you wish to know more, please contact me.


    • The distillate’s I’ve tasted have not had the characteristic taste of decarboxylated oil. I’ve even achieved completely flavorless state from distillation.


    • Posted by redturtle984 on April 17, 2016 at 12:33 AM

      It took an impacted left lower molar on me and a weekend wait with just extract for pain to fully understand why I personally need to completely decarboxylate my extract. The nutty flavor is just a side benefit really. When I had raw nerves yanking my brain around from the impacted molar I would seek relief by trying to vape.

      God explains things to me through my nervous system. When I vaped “uncooked” extract, I discovered it triggered intense pain the instant the vapor came into contact with the painful tooth. Don’t worry. I survived the tooth, but without any doubt I know that fully cooked extract did not trigger that tooth pain on contact.

      I surmised that my extract therefor was not becoming fully bioavailable to my body, on both a belief that it was the acid form of thc that was triggering the pain in the raw nerves of my tooth on contact, and experience in dosing in which the same medicinal relief I get from extract is greatly intensified if I “pre-cook” the extract until it stops bubbling in a small dish. About 10 mins or a bit more. The high is intensified orders of magnitude when the extract is made fully bio available. Thre is no way the extract is allowed sufficient time in a vaporizer to decarb the acid for of thc fully. It takes several minutes. The belief that the thc degrades substantially during full decarbing is understandable, but false. There is no evidence I have seen of any informational worth that confirms thc is capable of degrading spontaneously in just the presence of heat after it has degraded from the acid form (decarboxylation) into the form that makes me high (destressylation).

      There is much dogma surrounding marijuanna and the products thusly derived. There are a lot of folks in Oregon now sniffing around trying to catch scent of where the end of the rainbow is ($$$) I think lolz. I suppose everyone needs to pay their bills.

      I suggest using the product fully decarboxylated, which will turn browner (browner is a word if you are stoned so shut up!), and will inherit a delightful nutty flavor as it is heated. It bubbles like fizzy cola then stops bubbling completely and has a delighful sweet smell that makes my mouth water a bit. Yum. I use a 60 watt onfared heat lamp sold at Petco to do this because it is flat when pointed up and my small stainless steel pot sits nicely on it. About 10-20 min until bubbles cease completely works wnders on the stuff. Petco has best stuff for sophisticated extract users. Reptile section.

      Humans really do not do all that well with most uncooked things I have learned. Cooking the extract does not destroy thc in extract in a spontaneous fashion or I am a damn fool.



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