Polishing extracts

Some MMJ applications require greater purity and potency, so it is desirable to remove inactive ingredients like fats, lipids, and plant waxes, as well as any chlorophyll and other water solubles.

When I class chlorophyll with the water solubles, it is not in the same vein as the term is used in inorganic chemistry and is more involved.  Chlorophyll itself has a polar head and hydrophobic tail, so it is mostly non soluble in polar water, but can be removed from the plant and conveyed by water as micelle.

Water also dissolves and washes away the Chlorophyll binding proteins and exposes the Chlorophyll to the solvent used.  Chlorophyll is highly soluble in alcohol and slightly soluble in butane.

For further discussion of that subject, please see: https://skunkpharmresearch.com/chlorophyll-pickup-in-extractions/

Processes that use a polar solvent and reflux or soxhlet to maximize extraction, also maximize and concentrate chlorophyll, which can be a problem for some people.  The poison is in the dosage, so even for a salubrious ingredients like chlorophyll, some people can get too much of a good thing, producing digestive tract upsets, with attendant vomiting, cramps, and diarrhea.

See: http://www.nlm.nih.gov/medlineplus/ency/article/002893.htm  for details.

In a nutshell, many water soluble non cannabinoid ingredients come along for the ride when a polar solvent is used and water is present. While it is easier to use a process that minimizes their extraction in the first place, if that is a moot point, because you already have an extraction with excessive non-active ingredients, here are some ways to clean them up?


After re-dissolving the extract in ethanol or hexane, it may simply be filtered to remove the material that is insoluble.  We usually use coffee filters for this purpose, or if we have a larger amount, we use a Whatman # 1 lab filter, with a vacuum assist.

If we wish to filter it further, we run it through 0.45 or 0.2 micron syringe filters, which takes out any remaining plant material, as well as any bacteria present.


When using non polar solvents like butane and hexane, some non-polar waxes, fats, and lipids are extracted as well.  An easy way to get rid of them is to simply re-dissolve the non-polar extraction in 190 proof (~95.5% azeotropic) polar ethanol and stick it in the freezer for about 48 hours at -18C/0F, for the waxes to coagulate.

The waxes will precipitate out of solution as the temperature drops and clump together so that they are easily filtered out with a standard coffee filter, or a Whatman #1 lab filter.

Here is what a winterizing filter cake looks like, while still wet.

After filtering, the alcohol is evaporated or vacuumed off, to leave a pristine Absolute.

Winterizing ISO, Methanol, and Denatured alcohol extractions:

Even though Ethanol is polar itself, it can still be used to remove some of the undesirables they pick up, because it is not as aggressive a solvent as Isopropyl and Methanol.  By re-dissolving their extracts in hot ethanol and then placing that in the freezer overnight, some of the undesirables will precipitate out and may be filtered out.

Removing minor green coloration:

Because butane is non polar and considered insoluble in water, it is the longest chain alkane that is still slightly water soluble at 0.0325 vol/vol (3.25%).  That means that a liter of n-butane will actually hold as much as 32.5 ml or mgs of water (1000ml X 0.0325).

3.25% by volume is also enough water to bring along some water solubles like chlorophyll and leave an otherwise pristine extraction with a green tint, usually light and sometimes a gorgeous electric hue.

These light green hues are easily removed without the more involved and extreme measures that I will follow up with, and is as simple as putting a jar of the oil suspended in an ethanol tincture, in sunlight or a light from a high UV source, like a grow lamp.

The UV radiation in the sunlight will quickly break down the chlorophyll and the breakdown products are amber, so the green color disappears.

Alas, UV radiation also destroys cannabinoids, but fortunately at a much slower rate, and three or four hours in the sun is usually enough.


Oops!  Soooo, what if the extraction is really, really messed up, or if you just want to see how purdy you can make an extract?

Sometimes bad things happens to good oil, and evil spirits need to be exorcised, or sometimes the most economical process, or indeed the only available extraction process, extracts undesirables.  Fortunately there are ways to remove undesirables, though at the expense of yield and some of the other terpenes, so there is compromise involved.

Alcohol/Hexane wash:

One way to clean up an alcohol extraction, is to reduce its volume to a manageable level given your resources, and pour it in a separatory funnel to about the one third level, followed by the same volume of n-Hexane and then of water.

We use an HPLC Reagent grade for this purpose, which we get from the local scientific supply store.

Shake well and then lift the lid long enough to burp any pressure, before setting it in a stand to stratify into layers.  After it has separated, bleed off the water and emulsion layer.  They contain both the undesirables, and the alcohol as well, with the cannabinoids left with the hexane.

Add water again and repeat the wash step until you are satisfied with the clarity, before evaporating off the hexane, to yield the pristine oil.  More on hexane purging in the subsequent process description for serious scrubbing:

To put this process into perspective, I once collected all of my pipe bowl  scrapings and roaches until I had about a pint of them, and dumped that into the container of black denatured alcohol, that I had been cleaning my pipes in.

I shook the mixture well and let it soak for a day to extract the material from the roaches and scrapings, before straining it through a wire strainer and then a coffee filter.

Because I didn’t want to mess up a separatory funnel with the black foul smelling mess, I poured the solution in a 1 gallon Ziploc bag, to which I added equal amounts of water and hexane.

After shaking it well, I hung it from one corner, to let it stratify, and after it had, I clipped off the lower corner of the Ziploc bag, and by pinching it, and controlling the bleed rate, I was able to bleed off the water, alcohol, and emulsion layer, so that only the now gold hexane solution remained.

I filtered the hexane and poured that into a Pyrex pie plate, which I blew air over with a fan to evaporate off.  Attached are pictures of the amber oil that I extracted.

While the black color was gone, slight ashtray undertones could still be tasted, so further refining was necessary with activated charcoal, but we will cover that as a separate subject.

I am not suggesting this process for reclaiming ashtrays, but simply to make a point.

Hexane/Saline water wash:

Joe came up with this process, which has produced our most pristine creations.  It involves  re-dissolving the oil in a hot highly non-polar solvent such as hexane and repeatedly washing the solution with saturated salt water until it is mint quality.

Salt water washing uses a separatory funnel as above, but we start out dissolving the extraction to be cleaned directly into hot n-Hexane, and then washing the hexane solution with saturated salt water.

The magic trick is two fold.  The saline exposes any proteins hydrophobic surfaces, making them insoluble in water, so that they precipitate out, and the saturated water has no room for anything but the alcohol, which aids that process.

We start out by making four or five liters of saturated salt water in a glass (or ceramic) container, by mixing sodium chloride (table salt) in hot tap water with a hand mixer until no more will dissolve. We buy the salt cheap by the bag, using salt intended for water softener use.

We perform the salt water wash of the hexane mixture, by simply pouring the salt water and hexane into the separatory funnel together in about equal parts and shaking well and burping, before allowing the mixture to separate out into layers.

After carefully bleeding off the bottom layer of water, we continue to replace it and repeat the wash process of both the emulsion layer and the hexane solution, until the emulsion layer disappears and the hexane has bell clear clarity.

At that point we stop washing and evaporate off the hexane. While we use HPLC grade hexane, light naphtha containing only Pentane & Hexane will also work for this process.  Check the MSDS because the word light naphtha only means it boils between 30C and 100C, so it can contain Benzene..

Purging Hexane:

While n-Hexane is a delightfully non polar solvent, that enables us to do some amazing things, it has two more carbons and four more hydrogen atoms in the chain than Butane, and so due to the greater Van der Waal forces involved, is not as easy to get rid of as Butane.

The most effective way that we’ve found to remove the residual hexane, is either with multiple ethanol washes, usually around three, or thin film vacuum.

To wash with ethanol, redissolve the hexane honey oil in ethanol at a ration of about 10 to one and boil off the alcohol.  When it is almost all gone, do it again, and repeat, until there is no decernable hexane odor.

For thin film evaporation, we place about .200 inch of it in a six inch Petri dish, which we place in a vacuum chamber and evacuate down to 29.5 mm Hg and ~80F for 30 minutes.

N-Hexane boils at about 69 °C/ 156 °F and has a high vapor pressure, so it is easy to evaporate, but harder to completely purge.  Given our 30ppm taste sensory threshold and our 130 ppm odor threshold, we can detect its presence, long before we reach levels of concern.

Because it is a simple Alkane and relatively non toxic, hexane is used extensively in food extraction, but should not be viewed as being as salubrious as mother’s milk.

The first clue of course, is that it doesn’t come in nearly as attractive a container, and the second is the MSDS information which tells us, that in excess, N-Hexane attacks our nervous system.  The following is a typical MSDS Section 8:


Section 8: Exposure Controls/Personal Protection

Engineering Controls:

Provide exhaust ventilation or other engineering controls to keep the airborne concentrations of vapors below their respective
threshold limit value. Ensure that eyewash stations and safety showers are proximal to the work-station location.

Personal Protection:

Safety glasses. Lab coat. Vapor respirator. Be sure to use an approved/certified respirator or equivalent. Gloves (impervious).

Exposure Limits:

TWA: 500 (ppm) from OSHA (PEL) [United States] Inhalation TWA: 1800 (mg/m3) from OSHA (PEL) [United States] Inhalation

TWA: 176 (mg/m3) from ACGIH (TLV) [United States] SKIN TWA: 50 (ppm) from ACGIH (TLV) [United States] SKIN TWA:

500 STEL: 1000 (ppm) from ACGIH (TLV) [United States] Inhalation TWA: 1760 STEL: 3500 (mg/m3) from ACGIH (TLV)

Section 11: Toxicological Information

Routes of Entry: Absorbed through skin. Dermal contact. Inhalation. Ingestion.

Toxicity to Animals:


toxicity (LD50): 25000 mg/kg [Rat]. Acute toxicity of the gas (LC50): 48000 ppm 4 hours [Rat].

As the saying goes, the poison is in the dosage, so leave us please keep N-Hexane’s potential nature in perspective, which includes never losing sight of it.  Note also that oxygen in a breathing atmosphere greater than 75% pure will kill us dead!

A review of the hexane Material Safety Data Sheet shows that the oral rat LD50: is relatively high at 25000 mg/kg.

Acute toxicity of the gas (LC50 rat): was 48000 ppm using 4 hours exposure data and the Threshold Limit Value for an 8 hour weighted average in breathing air is 500 ppm with a Permitted Exposure Limit of 1800 mg/M3 (~ppm).

Studies of shoe repair folks suggest that long term chronic exposure at lower limits can have long term effects, because the liver converts n-hexane to Hexane 2.5 dione.  Their chronic exposure was many times what you would encounter in purging residuals left in oil that is below sensory threshold.

Besides NIOSH, we also have U.S. Department of Health and Human Services, Food and Drug Administration, Center for Drug Evaluation and Research (CDER), Center for Biologics Evaluation and Research (CBER) regulating what you can use and what you can leave behind:


They list n-Hexane as a class two solvent with 290 ppm concentration limits, and a total PDE of 290 mg/day.

The good news is that if you are out of the stink or taste, you are less than about .01% of TLV, but the bad news (?) is that although it is relatively non toxic, hexane still tastes like lighter fluid below toxicity levels, with our 130 ppm sensory threshold far below the Threshold Limit Value.

715 responses to this post.

  1. Posted by redturtle984 on December 26, 2015 at 9:44 AM

    I “clean up” the dispensary extracts using rubbing alcohol. I put the dispensary extract in a couple of tea bags. I cover them with rubbing alcohol. The extracts slowly leach out. I wring the tea bags and am left with white waxy stuff and other solids.

    I put the small jar with iso washed extract in a small jar and put that jar in front of a small fan so the surface just ripples. I come back later and the iso mix has turned white from the waxes and the oils with the magic precipitate out. I siphon off the amber precipitate with a medicine dropper.

    I pre-heat my oven to 250 F. I put the iso/extract mix now onto a preheated cookie sheet. It begins boiling off the iso/water immediately. About 5-10 minutes later the bubbling settles down so it looks like fizzy cola a bit with uniform and slower bubbles.

    I remove and put in freezer. In minutes it hardens into tiny air pocket ridden pieces. I pick the pieces off with frozen tweezers. The result is thick liquid at room temp, but hard as a rock in the refigerator. It is amber and clear and can vape with very little respiratory irritation.

    There are variations; if I am in a hurry, then I add salt to the iso/extract mix (non-iodized). This separates the iso from the water and immediately concentrates the iso above the water. The relatively pure iso evaporates off much much quicker after the rubbing alcohol has been “salted down”. The salt, if any, left in the extract is not detectable.

    Good luck. May Life not life on you too often.


  2. Posted by JDbgt on December 15, 2015 at 12:51 AM

    I tried this with some older trim that was run with butane. Ended up a little dark so I ordered a gallon of hexane, warmed some up, and dissolved oil in it. Added saturated salt water like instructed, shook, separated, and drained water off, and color did not change. Any suggestions?


  3. Should you add the everclear to the butane/oil before it has evaporated?
    Can the solution just be left to air dry for several day’s?, or do I need to
    do a vac purge? thank’s for the information


    • Absolutely. No reason to wait to add the alcohol. It helps purge the residual butane.

      It would eventually air dry in a thin film, but vacuum is so much faster, and more reliable. The good news is that ethanol is not insalubrious below 5000 ppm, according to the FDA pharmaceutical standards.


  4. Posted by OldOyler on November 5, 2015 at 6:24 AM

    Peace and good things to the Skunk Pharm!

    I had some weedahol (Green Dragon) that was clearly not decarbed before hand. It had 1/2 dram of LorAnn raspberry flavoring in it (PG, color, flavoring). I decided to cook it into a decarbed QWET oil (I follow your HOA recipe, sublingual) after straining, freezing, and straining again, but when it came time for the final 1/8″ of mash that was left, it just wouldn’t (visibly) go to decarb at 250F (I noticed a rainbow sheen to the bubbles), so I stopped and decided to try and air dry the remaining ethanol off. It has been two days, and I have the usual black blobs that I can redissolve again (I have a good 5 grams of actual oil by eye estimation), but there appears to be about 2 tbps of red cough syrup that smells strongly of raspberry that doesn’t appear to be willing to simply evaporate. I even asked nice.

    I don’t have access to butane, I am pretty much a double-boiler type QWET setup (NuWave w/candy thermometer for the cooking oil, stainless steel 2 cup UKonserve container for the mash/oil).

    I figured I can just add it to something and drink it (my body is not a big medibles fan, only what slid down as leftover in my mouth from sublingual use), but would love to be able to simply RSO it.


    • If you put the extraction into a 250F double boiler, the puddle won’t reach higher that the boiling point of ethanol and its azeotropes, until they are boiled away, and then it will rise to 250F. At 250F, there won’t be alcohol or water left.


      • Posted by OldOyler on December 10, 2015 at 6:35 AM

        Thanks Skunk Pharm! Sigh. I realized I need to stop putting the eventual “carrier” type materials right into the just-finished cannabis oil while it is still in the mash container – that will keep me from having to salvage anything in a polish maneuver. I’m always looking for you folks to clean up my ongoing (and seemingly neverending) RSO apprenticeship… 🙂

        I usually make a QWET into your HOA formula, batches of 1-2 ohzees per batch, and so I usually just add the coconut oil, cinnamon oils, etc. into the stainless steel container the mash is in whilst still hot after coming out of decarbing in the 250 oil bath. I do the same if I am making vape oil – I use a PEG mix (EJMix, lower temp for most of the purge of course), and add a little flavor, all right in that mash container.

        So from now on, I will only do “mixing” outside of my main mash tin – that way I can still reclaim the little bits of precious. Your time is always much appreciated, Skunk Pharm.


  5. Posted by Neelima on July 18, 2015 at 9:09 AM

    Hi Thanks for the valuable knowledge. I came across a problem with onion extraction in ethanol and I ended up with a pasty mass. I wish to retain the antibacterial properties of the extract as well as wish to obtain a powdery product. No matter how hard I dry the the ethanol, the pastiness exists. Please suggest.


    • Your “pasty mess”, from your description is H2O still in your Onion. When you prepared this, was the Onion “Dried”? If not, there’s your problem. C2H6O(Ethanol) wil atract and retain H2O. From the sounds of it, you say you can’t get it to dry out.

      I would first, dehydrate a Onion. 100% no moisture.
      Then, pulverize/blend into a fine consistently. In a ball jar, with a lid put in your Onion, then add 3x the amount of Ethanol.
      Shake well, stick it in the freezer fro two days.
      Now remove from freezer, work it cold, and filter the fluid.
      Depending if you want to recapture your Ethanol or not, the next step is to remove/reclaim your Ethanol.
      Method #1, pour your fluid into a glass, Pyrex pie plate, place a small fan in front to blow over the top. Make sure your work area is dust/contaminate free.
      Method #2, rotovap, or any other way to reclaim.

      What is left, is “Absolute” Onion extract.


  6. Posted by Ron Davis on July 13, 2015 at 4:54 PM

    Ever try winterizing at -80C (or anything lower than 0?)


  7. Posted by Guapo on July 1, 2015 at 4:39 AM

    Hello!! Thank you for sharing such wonderful information.

    Could you please tell me what that bottle top filter contraption is? Or please point the way to where I might be able to purchase the same one?

    Thank you again and best wishes!


    • That is called a “Seperation Funnel” they come in various sizes. Looks like a 1000 ml Sep they are using in the photo. This is to separate mixtures, in time. Like oil and water, shake it up, and you trap bubbles. Let it sit still for a few day, and the two fluids separate. Then the bottom portion can be removed through the bottom port.
      You can purchase these on Amazon.


      • Posted by bongstar420 on November 3, 2015 at 6:26 AM

        If you need to explain it, maybe the person you are explaining it to shouldn’t be doing it.


      • Posted by Aaron Corey on December 8, 2015 at 11:39 AM

        @mylkingtrees Ummm dude3, hes referring to the filtering funnel on top of the bottle… @Guapo sir the pirce of labware that you are refferring to and that this man is faiiling to correctly inform on is called a “Buchner Funnel” It is usually used in conjunction with an “Erlenmyer Flask” with a vaccum port feature, a filter paper is placed in the filter funnel an a vaccum is applied to the port on the flask, when filtering flow slows down from a clogged filter, vaccum is turned on to assist in speeding up the process. easily avail at any glassware supply lab supply, or with the correct search term, on amazon .


  8. Posted by Jordan on June 13, 2015 at 8:41 AM

    That hasn’t been my experience where over saturation had helped to precipitate out of the fats, definitely hard to find that balance and I’m not sure the advantage would be worth it


  9. Posted by Silversouth on June 2, 2015 at 11:38 AM

    Is there any way to distil or clean the Hexane after it has been used to clean the oil? If not, what do you do to dispose of the used Hexane?


    • OK, since that made no sense what-so-ever, let me try again… Is there a way to evaporate the hex and condense and recover the solvent for re-use?


      • I have a closed loop recovery system for ethanol so I wonder if Hex can be recovered in a similar manner…


        • I don’t know what kind of “closed loop recovery system” for Ethanol, you are referring to. A rotary eveporator would be the best method for evaporation and recovery. Plus what ever system you are using, reduce the vacuume as much as possible, not to exhaust your Hexane vapor. Lastly, Hexane is as explosive as gasoline. Evaporate and condense under a vac hood, with proper CFM moving. Have your vac exaust vented outside, or into your hood. SAFTEY FIRST!


          • Posted by bongstar420 on November 3, 2015 at 6:28 AM

            Condensed ethanol vapor is equally as flammable…you ever ignited boiling alcohol

            it goes up really fast

        • Yes, a condenser like the Hex would work fine with ethanol and is the same basic design that I built our ethanol recovery still with. https://skunkpharmresearch.com/alcohol-reclaim-still/


          • Posted by Anom on June 13, 2015 at 3:29 PM

            Yes, and thanks again for the design ideas. The Cuisinart Fondue cooker works like a dream! I ended up just evap-ing hex into the atmosphere on my maiden voyage. Still did not end up with golden color but the resulting dark colored oil is really strong. May not have had the salt water saturated enough. Still has a hint of the nasty taste of the starter material (I used some REALLY nasty cast off stuff) but pretty amazing to get a small amount of kick ass tincture from junk. Best I can tell, no discernible gasoline taste after 3 ethanol washes. You guys rock!


      • Yes, a self draining graham hex type heat exchanger will work with alcohol.


    • It can be distilled off and recycled.


  10. Posted by Johovah Bernstein on April 24, 2015 at 2:30 PM

    some pretty good info here, thank you.
    Neat trick to remove the green tint.


  11. Posted by Jordan on April 24, 2015 at 1:17 PM

    Is there any advantages to using organic grape alcohol Over everclear?


  12. Posted by DongJohnson on April 6, 2015 at 12:51 PM

    Hey SkunkPharm guys,

    Ive been trying the hexane/alcohol/water, as well as the hexane/saline wash with zero results. Ive done everything to spec provided in the article and am wondering if there is something im missing. Ive ran the expirement close to a dozen times. Each being a complete failure.

    To give a little back round, im trying to polish a bho extraction thats blacker than a thousand midnights. Ive used both ethanol and methanol to dissolve the extraction before mixing in hex/water. Expirementing with approx. 2g of extract in 50ml of alcohol. Emulsion is poured into separatory funnel, followed by 50ml of hexane and 50ml of water. I give it a good shake and burp as advised above. The mix separates and I bleed off the bottom layer which looks a bit cloudy/opaque white.

    The top layer remains just as black:(

    The same can be said about the hex/saline….

    Can anyone give any insight into what is the problem? Am I missing something? Or is it that this method is exclusive to an Alcohol extraction and wont polish bho or co2 extracts….

    Thanks in advance!


    • Posted by bongstar420 on November 3, 2015 at 6:38 AM

      I get pristine oil from straight ISO washes…as clear as good BHO

      about 70%-90% extraction efficiency

      Try extracting with Hexane, then redissolving in Etoh, then freeze precip, then redry.

      Stop being cheap if you want quality


  13. So say I was to do a tincture by slow steeping/aging in grain for 60 days, can that too be polished? How about a VG/PG tincture via slow steeping for 60 days? I imagine that would be difficult as the base substances are thick and coagulate at colder temps ruling out winterization but I am wondering if there may be another technique for that.


    • Posted by bongstar420 on November 3, 2015 at 6:39 AM

      Why would you waste time on that…a tincture is best as full spectrum as possible..

      “cleaning” the extract is for folks that want Cannabis crack that vapes off with no residue.


  14. Posted by Guerric on March 26, 2015 at 4:51 AM

    Denatured alcohol??? Is that safe to use?


  15. Do you have a recommendation where can one obtain 190 proof EtOH? I live in PA. |
    Thanks so much!


  16. With the NaCl and N-Hex, can someone please tell me the range of temperatures that need to be used? Have noted that “hot” Hex is essential to the precipitation of the solids and chlorophyl. What is the range of temps that have provided consistent results.? Thanks in advance.


  17. Posted by Tommy on February 23, 2015 at 2:43 PM

    I am learning SO much! Thank you!

    Two questions:

    The ethanol: how do i make shure i get the right type of ethanol?
    All i can think of i can get my hands on is for Bio-ethanol burners will that do? Hexane is not possible for me to get.

    can you further explain the technique with the jar in the ethanol tincture in the sun?
    How big of a jar, why the tincture, is the tincture just ethanol and water?

    Again, thanks a million 😉


    • Posted by Tommy on February 23, 2015 at 3:08 PM

      This is the Bio-ethanol i can get my hands on, its meant for bio ethanol burners, they are wery popular because of the beatifull flames.

      Bio Ethanol DB-07 >96%


    • Posted by bongstar420 on November 3, 2015 at 6:43 AM

      The only “right” type is clean and dry…USP is that


  18. Thanks for some very insightful lab work to both of you. Only had a couple of question, if you have the time—

    1. How many salt bath washes did it take to get to the golden stage – approxiately?

    2. How long is the average ‘standing time’ after the first couple of baths? It seems like the separation is taking place in just a few minutes – 5 to 10. Is that reasonable?

    Thanks in advance for your help and insight. God bless.


  19. Posted by Heidi on February 9, 2015 at 9:20 PM

    Nice work!


  20. Posted by Heidi on January 25, 2015 at 2:25 PM

    We are really interested in live resins and I am trying to dial in the freezing process to remove the chlorophyll from the fresh organics before starting the extraction. I have read mostly that the freezing process is done over about a 24 hr period. Have you ever experimented with flash freezing? I am not sure if this would rupture the plant cells and in turn allow more chlorophyll to be extracted.
    Thanks for all the great information!


    • If you are trying to “get rid of Chlorophill “. After you run your material, and your solution is green. Set it in direct sunlight, or UV light, until golden! 1/2 hr to a couple hrs. Watch closley, try not to heat up any more than needed. Now winterize as normal, and the particulates will filter out.


      • Posted by bongstar420 on November 3, 2015 at 6:45 AM

        That degrades the chlorophyll…not gets rid of it
        Also, freezing doesn’t “get rid of chlorophyll” either.

        It slows down how fast it dissolves as chlorophyll is more effected by cold temps that the drug are with respect to dissolution rates.

        Some school is in order for you folk


  21. GW, I unfourtunetly still have to open blast. I use a “N-Butane”3.25 ml per can. USA made, so I would think it would have to follow standards for “product advertised”!
    With that said, I DO notice a considerable difference in my product.
    My question is, I use, 3.25 ml per 14g of material, then once blasted into a quart mason jar, I add 150 ml of 190 proof Everclear, slowly, to every 3.25 ml of NB. This lets the NB precipitate out at a faster rate, and once NB IS TOTALY removed(stops bubbling), I then freeze(0*F) for 48 hrs. At the same time I have frozen a 300 ml Büchner funnel with fine frit.(1.5mic). After vac filtering, and fats, waxes, lipids have been removed, and prepped for a final wash.
    I reduce the solution(reflux) to a workable amount. Then add in a Sep Funnel, solution, 1-1/3 N-Hextane, then 1/3 NaCl? Shake Seperate, repeat until clear?

    Then the TOTAL evacuation of N-Hextane.
    Once the solution is reduced(refux), can I add “Pet Ether” to remove residual NH, by reflux?

    Or can I skip NH all together and use just PE for final wash?

    I hate Neurological toxins in ANY(PPB) amount! Please advise.


  22. The removal of N-Hexane in a RotoVap, can the final wash for removal be with “Pet Ether”? Seeing both are light carbon, and Seperate easily with water. OR can the entire wash be done with PE/NaCl, leaving the N-Hexane on the shelf?


    • Posted by wolfman on February 4, 2015 at 7:37 AM

      entire wash in petroleum ethers should be fine as hexanes and PE are often used interchangeably, just wash more times with EtOH to remove less volatile components in the PE


  23. Posted by heino herrmann on January 11, 2015 at 4:47 AM

    Great stuff bro! Keep up the goodshit!


  24. Posted by David on December 30, 2014 at 12:10 PM

    I love this post… so much great info… thx!

    Is technical grade Hexane suitable for use in extractions and/or reclaim?


  25. Posted by profinikki on November 13, 2014 at 6:57 AM

    I wonder why would it do that, when you mix hexane, ISO, and very salty water, it separates into two layers – water, and hexane and alcohol, and I wasn’t able to fix this at all, no matter what order I mix them in or how long I leave them to separate. Does it take a few hours for alcohol and hexane to separate, or should that be faster? Also, what do you mean by an emulsion layer? Any response would be greatly appreciated.


  26. Posted by Josh on November 13, 2014 at 3:44 AM

    Good to know I can get rida that green tint! Thanks a lot guys


  27. Your style is very unique compared to other folks I’ve read stuff
    from. Thanks for posting when you’ve got the opportunity, Guess I will just book mark this web site.


    • Posted by LOJ on October 28, 2014 at 6:16 PM

      Yeah, this guy seems to actually know what he’s talking about!

      Awesome info, thanks and keep up the good work.


  28. I’m wondering if I add water to my everclear tincture and freeze it, will the water pull the chloraphyl and plant wax out and freeze it into a big ice cube (without destroying the tincture)?


  29. Posted by Stacey on September 11, 2014 at 11:27 PM

    Just out of curiosity…am I doing something wrong by wanting to keep the chlorophyll in my mom’s cancer-treating extract. I specifically have avoided trying to remove the “green” to help keep her cells alkaline and oxygen-rich which cancer hates, and chlorophyll provides. Is this entire thread based on removing chlorophyll for “recreational use” or am I missing something here. Please help, because I thought I was doing good. o.o?


    • Posted by guest420 on October 5, 2014 at 6:10 PM

      Chlorophyll upsets people’s stomachs most times, and lends to a less pure product in terms of concentrated cannabis. So a gram of cleaner product may be 70% THC where a less clean product is 40% THC, so you’re getting less cannabinoid material, which you can really get from cannabis, whereas there are numerous other ways to get chlorophyll. It also does not help in digestion or bioavailability. You’re not doing it “wrong” but, you could be doing it more efficiently. More medicine at once means faster healing times, generally.


      • Thank you so much. This is very helpful. 🙂


      • We’ve had success using this modified process. Heat ISO to 125. Mix in material 4 parts material to 5 parts ISO. Stir 10-15 minutes, continual heat. Repeat. 4 parts material to 5 parts liquor (add some ISO to increase volume). Repeat. 4 parts material to 5 parts liquor (add some ISO to increase volume). Pour off liquor each time through screen. Discard material in industrial garbage bag with one corner tied and suspended. Drain in container. Add some ISO to increase drain of remaining liquor from material. Place liquor in direct sunlight or high intensity UV light for 2 ½ hours. Also, a Petsmart UV light Pet Urine checker using the cheap batteries can be used overnight. Place liquor in ISO bottles. Mix in 4% H2O. Freeze in DRY ICE overnight. Pour liquor through Industrial Coffee filter. Squeezing the access liquor through the filter by hand with rubber gloves to expedite the process. Put liquor back in ISO bottles. Mix in 4% H2O. Placing liquor bottles back into the DRY ICE as the process continues. Again, Pour liquor through Industrial filter. A large tub with two screen holders is ideal. While one drains, the other filter is manipulated like a gold pan, lifting the edges and spreading the liquor for full filter contact. After the liquor level in the filter paper has dropped, the edges can be gathered. A slight goo or gel will form on the filter paper. Lift the edges to form a drain, and pour into the fresh filter paper. The liquor will divide from the gel as the pour ends. Replace, and continue. Replace, and continue. The liquor is now double filtered. Cook at 250 Fahrenheit in mixing bowl placed in oil bath electric skillet. When little bubbles cease, remove from heat immediately. Use spacer to avoid direct contract with heating element. When ISO is cooked off, add water during decarboxolation process. Mixing constantly with rubber spatula. Use Gas Mask purchased from Welder Supply for fumes. A fan is used to disperse fumes. Rubber gloves are a must. Our numbers were 58% to 67% effective cannabinoids utilizing ‘high quality trim (bit of bud)’ and ‘sugar shake’. No solvent residue. Appearance is a very dark golden-brown. 12 gallons of ISO will process a barrel of starting material. Some recommend fingernail/manicurist suppliers for cost effective purchase of ISO.


  30. Posted by Jack on September 10, 2014 at 5:27 AM

    I just ran 30g of skywalker nugs chopped up grade AAA I used the vacuum flask method the soak time was 1h:30min the tane used is newport 2 cans, after the tane had dissipated I poured in 50ml of 99.9% iso and began to desolve the oil and put it in the freezer for 40 mins for the wax’s to presipitate then poured it through a coffee filter and then through a 0.2um syringe filter. After evaperating the the alcohol off I then placed it in the chamber and began pulling down to 29.5hg at a near constant temp of 110F for about 10 hours.

    I stopped when it was at the point where it had just started ot become shatter (pull n snap! but still too sticky & taffy to play for with long) the smells coming off this are rediculous just like the Bud lemon fuel funk mmmm!! but when i hit it there is a weird taste but smooth as air the taste was like green paper towels smell if you get what i mean! follwed by a tiny faint sweet taste and then nothing what did I fo wrong ? I never went over 120F out of the vac and 115 in the vac and never below 29.5 did I vac too long for winterized concentrates Im pretty sure all the solvent had left by the 5th hour but i kept on going due to the fact i did not want to take my chances with the iso I apreciate your feedback and any pointers you can give me
    also I ony just started winterizing. The shatter looks so bomb though and so clean although extreemly dissapointing on the flavour because the last batch i made from the same strain that i used tane only came out much better with tones of flavour and the same purge time and no filtering.


  31. Posted by Soli on September 9, 2014 at 11:50 AM

    Would it be possible to use heptane instead of hexane for this process?


  32. Posted by Javier on July 30, 2014 at 10:51 AM

    Purge question:

    If im In florida, 6 feet above sea level, what should i consider when purging and blasting?

    Inside chamber while at full pressure (29.9) is it hotter inside the chamber due to lower pressure and should i listen to everyone saying 110-120. Or should i have the griddle way lower?

    Is bho honey reversable? Can it turn into shatter after being decarbed?

    Humidity has to be a problem for me. Open blasting in summer time breeds so much moisture in my product. What can i do to help? How can i filter the moisture out? Please help! Done about 10 runs and have never gotten shatter.


    • Posted by Javier on July 30, 2014 at 11:03 AM

      Also the best way to purge everclear out of oil? Open air, pyrex over boiling water, griddle?


      • Posted by guest420 on October 5, 2014 at 6:12 PM

        can’t answer the first, but, if you’re dabbing, let the Everclear just air out. You’re not getting many terps with the alcohol, and heating at all will destroy any you have. It’s a bitch to wait for the 5% water to dissipate, but it’s worth it for taste, imo.


        • Use molecular sieves to dry your organic grape alcohol/ BHO extract while in solution.Its also a good idea to “dry” your alcohol while storing. Mole sieves #3 is the recommended size. I use them in my post work up, clean up for both my BHO and C02 applications. I store them in the bottles and filter out and dry them in the vac oven and reuse repeatedly. Obviously I had the need to do this as there is quite a bit of H20 left over in a C02 procedure. I usually dissolve my oil right out of the receiver vessel into OGA (organic grape alcohol) then filter, dewax, decolonization with activated carbon, dry with sieves (or alternately dry mag sulfate in a oven at 200F for 3 plus hours till rock hard and white) I prefer the larger sieves as they are easier to reclaim. Then drying via vacuum oven. The only trouble Im having is preventing nucleation. I understand that the bubbles get trapped as the oil starts to thicken and causes clouding then waxing. However it doesnt always do that. Is there something im missing here possibly community?


          • I’m no doctor but I did stay at the Holiday Inn. (Or something?) What you’re talking about far exceeds me but figured I’d do my input XD. Anyways…if it’s waxing then one would assume the product has contaminants, such as waxes. Are you keeping everything cold while filtering? Not keeping it cold will allow the waxes to warm and slip through the filters n what not.

          • Posted by beandipwashere on December 17, 2014 at 9:17 AM

            In my experience those have been “hot spots” where portions reached temperatures over decarb point. I could point to a spot on the shatter (post vacuum oven) and see a small spot where I recalled during a BHO extraction the first portion reached a high temp. The induction top that I was using for 100 degree butane burnoff ran as high as 170 degrees during start up!

  33. Posted by FatWhiteStoner on July 13, 2014 at 6:35 AM

    After going through all that trouble and getting my product looking right, my vaccum pump decided to spit oil back into the chamber and I’m back to square one. Is it fixable?

    I also have another question. Using 95% Everclear as a wash or for winterizing seems to make the oil darker. Is it the water reacting with it, or just my inexperience doing something wrong?


    • Posted by beandipwashere on December 17, 2014 at 9:23 AM

      Do you have a valve to close off between the pump and the vacuum chamber? If you hold a vacuum with the pump turned off and no shut off valve the vacuum created will suck the oil from the pump back into your system.

      At what point is the oil darker – upon adding the ethanol or post extraction and cook off?


  34. Posted by FatWhiteStoner on July 2, 2014 at 7:04 AM

    If you don’t have laboratory grade hexane, would it be better to use a good light naptha or would a purified no odor mineral spirits be acceptable?


    • The term Light Naphtha, only means that it boils between 30C and 90C, not what is in it. One of the things that falls in that range, is Benzene, which is often in light naphtha, so I recommend against it.

      Mineral spirits has too high a boiling point at 148C/298F, to be easily purged.

      Better to go the other way and look for Pentane.


      • Posted by FatWhiteStoner on July 5, 2014 at 6:51 PM

        Is there a significant difference between using Bestine, rubber cement thinner and solvent available at craft stores, (MSDS says 100% N Hexane) at $10/qt vs lab grade, which with delivery is about $40?


        • The Bestine MSDS that I’ve seen, lists n-Heptane, vis a vis n-Hexane. Heptane will do a fine extraction but is harder to purge than hexane.



          • Posted by FatWhiteStoner on July 9, 2014 at 1:02 PM

            Usually differences like that don’t get by me, but I’ve been really stressed and staying high AF to deal with it. I was literally in the area art store and noticed it then and had a WTF moment. I was able to seek your answer on the spot. I just wanted to say thanks. I ruined about twenty grams when I pulled the valve clean off this Heat Vac trying to take out just the stopper. Patty flipped right over onto the dirty metal surface and it’s cloudy and dark even after redissolve and filter with 95% Everclear. Thanks again for the help.

  35. When can we expect an article on ” activated charcoal “?


  36. Posted by bellski on June 25, 2014 at 1:46 PM

    n-hexan is a neurotoxic and u should think about usin n-heptan instead. even if it have a higher boilingpoint and is harder to purge


    • Posted by bellski on July 7, 2014 at 9:35 AM

      in germany labs and schools/universitys change from hexan to heptan as “standarddissolver” because hexan is classified as possible carcinogen


  37. Posted by Johnnyrex7 on June 22, 2014 at 1:58 PM

    When you say ratio 10:1 do you mean 10ml per gr of starting material before blasting through colums?


  38. […] Dude, I have no idea. I never winterized. Check this out though: https://skunkpharmresearch.com/gettin…ut-afterwards/ It's one of the best articles i've found on the subject. Reply With […]


  39. Posted by chad on February 27, 2014 at 7:28 PM

    Hey has anybody tried to use induction plates instead of griddles?


    • Haven’t had good luck with temperature stability and uniformity. I would still use a stone heat diffuser like granite or soapstone.


    • Posted by JSK on September 4, 2014 at 8:56 AM

      A Nu-Wave 2 induction cooker is a great investment. You can set the desired temp, and time without worry of the temp oscillating on you. Under a $100 at stores. A real work/time saver if you don’t have a true vacuum oven at your disposal.


      • Posted by beandipwashere on December 17, 2014 at 9:26 AM

        This had temps of around 170 degrees when it was set on 100 degrees so YMMV on that piece of equipment


        • Posted by Dominick on February 24, 2015 at 7:52 PM

          Correct. The Nu-Wave actual temps vs. display are significantly different. I used a professional chef thermo to verify the display, and it can be off by up to 40 degrees F, on my particular specimen. Use calibrated equipment, at least initially.


  40. Posted by Bobbybud on February 27, 2014 at 9:47 AM

    I want to make sure all of the ethanol is purged from a dissolved solution of oil/ethanol. Heat alone takes a very long time and I am concerned about fumes. Is there a vacuum chamber setup that one could recommend for this?

    I’m also working out ventilation for the Ethanol fumes, if anyone has a good suggestion I would love to hear it.


  41. Posted by Joe C on February 24, 2014 at 6:35 AM

    What would you recommended as a good amount of 190 proof per ml of bho to winterize? and what is the best way & @ what temp to evaporate ? Sorry for all the Noob questions & Thanks again for your help!


  42. Posted by david on February 22, 2014 at 4:47 PM

    I got Bhopal from someone and it’s green with some specs of marijuana in it. Is there any way I could get rid of it?


    • Redissolving in a nonpolar solvent and filtering will probably get rid of much of it. If not, try washing with brine.


      • Posted by robb on November 25, 2014 at 3:06 PM

        awesome site!, im kinda understanding but i just need a little reassurance here, i have about 7grams of dark sappy sticky bho, it tastes great but i think theres a bunch of butane in it, so all i need to do is take it and mix my oil with everclear, put it in the freezer for 2 days, then dump that mixture in a different container that has a coffee strainer placed over the top of it?


        • Posted by ZC on December 7, 2014 at 6:14 AM

          no u need to vac purge more, the only way to get the rest of the tane out cause, it is saturated in the oil, is to lessen the atmospheric pressure on the surface on the oil and allow the tane to separate from the oil and evaporate off more efficiently. actually simple high school level chemistry.


  43. Posted by Crunchy on February 14, 2014 at 11:34 AM

    What else can you use for winterizing other than the 190 proof polar ethanol?


  44. Posted by ryan on February 5, 2014 at 9:20 AM

    I use butane for the inital extraction. Then i use a naptha/ brine wash to clean it and evap the naptha with iso. I still end up with dark product. Should i add alcohol when i do the wash? Would hexane work better?


  45. Posted by ryan on February 4, 2014 at 1:07 AM

    I have been using butane for my extractions, I then dissolve the concrete into naptha as a non polar and a brine solution to clean it 4-5 times before evaporating the naptha with alcohol. I still keep getting dark shatter. What am I doing wrong? Should I be using alcohol with the wash too? Or hexane instead of naptha? Or should I just be washing it more?


  46. […] There are other methods for purging that does not use a vacuum chamber or heat. These use alcohol and are known as polar secondary extractions, or winterization. They can also be used to clean up your product by removing any lipids, waxes, fats and other non polar compounds you may not want in your product. Here is a link to this process. Polishing extracts « Skunk Pharm Research LLC […]


  47. Posted by Vrtra on January 31, 2014 at 5:19 PM

    So if I just have BHO and then winterize with 190 proof ever clear, at 29.95″ in the vac what is the correct temperature for the purge? 115F? Thanks


  48. Posted by miguel on January 30, 2014 at 10:58 AM


    First off what a great site. Thank you for posting so much information on this subject.

    I do have a question regarding winterization. Is there any way to shorten the 48 hour freezer time when filtering through coffee filters? Could liquid nitrogen be used to shorten this time?



  49. Posted by Tokeybob on January 29, 2014 at 10:12 PM

    -Woud bringing the alcohol to a super saturated state, by adding as much extract as possible while hot, then cooling it to precipitate out waxes, and filtering to make an absolute, pose any upsides?

    The way i see it, bringing it to saturation will make things that don’t want to be in the alcohol as much as thc, precipitate out faster than a solution that isn’t in a full saturation. Plus the filters could be saved, and all materials washed and reclaimed to be used on the next batch in order to collect any thc or cbds that may have precipitated out during the extreme cold, if that’s possible that is.

    -Would it be beneficial to use a vacuum assisted filtering apparatus with long hoses to connect from the freezer to the vac pump, in order to speed up the time it took to filter such a cold thick solution, or would it be more beneficial to run the super cold solution through a micron syringe filter.

    -and lastly, if i used the vac assisted filtering apparatus, would adding a chunk of ice to the funnel with the alcohol solution itself pose any benefits?


    • Posted by Karen on June 12, 2015 at 11:36 PM

      Have you worked this out via experimentation? I too want to get to a saturation point to maximize the alcohol + (your reason seems viable too).


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