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BHO Extraction

Butane Honey Oil, or BHO, is the essential oil from the cannabis plant, extracted using Butane as a solvent.  It can be extracted from fresh material or from cured material as a Concrete or an Oleoresin.  A concrete or an oleoresin that has been winterized to remove the waxes, lipids, and fats, is known as an Absolute.

Butane Honey Oil extraction refers to the method used to extract the essential oils from cannabis, and there are multiple theories on the best way to accomplish this, as well as what material is best to use.

Perhaps the first question is why use a BHO technique to extract the resins, instead of just boiling the material in alcohol to get the greatest amount of extracted material?

The answer to that is that because butane is relatively non polar, it doesn’t extract the water solubles like chlorophyll and plant alkaloids. Butane produces one of the cleanest extractions, albeit typically at a lower yield than polar alcohol.

Using closed loop extractors, we average slightly more than 20% oil by weight from bud, but as low as 5.7% absolute and as high as 28.1% absolute.

The first wash will usually extract 75 to 80%, leaving the balance for the second after repacking the column. The second extraction will be more sedative and less heady. If you use a hand microscope, you can easily see when the trichome heads are gone and the stalks look like wet fur.

We've only tried a few processes here at the pharm, and used to cover simple flow through columns, and using a thermos bottle, but now cover only closed loop systems, because of the number of brothers and sisters ignoring my caveats to not extract indoors.

We currently use a closed loop system for BHO, and I cover that process on separate threads named The Terpenators, where I will detail building our Mk I through second generation automated systems.

Before we discuss how to extract the essential oils from cannabis, let us talk about the plant material to be used.  That immediately brings to mind the qualifying question, "What do you want to use it for?"

Oil that is to be vaporized, is normally treated differently than oil that is used orally or topically, because it doesn't need to be decarboxylated.  For cannabis concentrates to be orally and topically active, it does require that the THCA and CBDA be converted to THC and CBD, by a heating or drying process.  I will cover that issue under a separate thread on Decarboxylation, so as to not clutter this post.


Besides the cannabinoids, which are Di-Terpene alcohols and di-alcohols (diol), there are also other terpenes in cannabis essential oils, which add to its smell, flavor, and medicinal entourage effect.  Some of these terpenes are highly aromatic alcohols, phenols, ketones, aldehydes, ethers, and esters, which are aromatic because they freely give off molecules at even ambient temperatures.

Heating the plant material or the oil to decarboxylation temperatures will evaporate off most of these smaller aromatic Mono-Terpene and Sesqui-Terpene molecules, before the larger and heavier cannabis Di-Terpenes are affected.  Decarboxylated oil is smoother to the taste, but basically tastes like hash, with the floral undertones gone.

Gone also are the medicinal and entourage effects from those terpenes.  The price we pay for decarboxylation, so we shouldn't decarboxylate casually, and should first consider the end use before picking the process.

One of our process  limitations, is that though non polar, n-butane has slight water solubility.  At 20C/68F, it is only 0.0325 percent by vol/vol, but not zero and is still enough to pickup undesirable water solubles.  1 liter, or 1000 ml X 0.0325 = 32.5 ml of  water.

With water, comes water solubles, which includes chlorophyll and plant alkaloids, that detract from the taste, so the dance is to maintain the volatile terpenes, while studiously avoiding the water solubles.

Freezing the water is one method that works well, but it is important that the material be dry when it was frozen and that it is not exposed to high humidity while frozen, or ice will form over the trichomes, preventing their extraction.

Another method is to simply remove most of the water.  This will produce pristine extractions, but doesn't preserve the terpenes.  If the material is to be decarboxylated anyway, that is of little concern, because we will lose them anyway.

We also have the issue of purging out the remaining butane, while preserving the terpenes.  Again, there are a number of ways to do that, but I will address only a few of the ways that have worked for us here.  Those are light heat, high heat, and thin film vacuum.

So, besides decarboxylation, what are some of the things to consider selecting a process and how should the plant material be prepared?

In our experience, for best flavor and taste, freshest material works best (less than 3 weeks old), whether it is fresh frozen material or dried.  Older cured material loses the nuances of the floral undertones and just tastes like hash.  That means that the degree of drying and curing is also critical, if your goal is to maintain maximum terpene content.

Oil from buds is tastier than oil from even sugar trim, because most of the terpenes are produced by the buds, and that is where they are the most plentiful.  Tasty is usually not a word used to describe oil from fan leaves or stems, though effective may be.

The absolutely most flavorful BHO extract to me personally and to the test panels thus far, is fresh picked buds, that are immediately frozen to tie up the water, and extracted while still frozen.  It produces an oil that abounds in whimsical flavors darting about and the word most often used to describe it by panel members, was the word "fresh."

Next most flavorful, from a BHO standpoint, is material that has only been cured 5 to 7 days, and is at the small stem snap stage, where you might jar it if you were curing it to smoke.

Part of the formula is of course the degree and methods used to purge out the remaining butane.  While there are a number of ways to do that as well, I will address only a few of the ways that have worked for us here.  Those methods are low heat, high heat, and thin film vacuum.

Butane supply:

Lastly, selecting a suitable butane source is a key  step, in that all butane sources aren't created equal.  n-Butane boiling point (30.2°F -1°C) is a simple alkane, with four carbon atoms linked together in a row, with the remaining possible carbon bonding sites taken up by hydrogen atoms. Iso-Butane is three carbons in a row with the forth carbon attached to the middle carbon in a "T" like conformation. This conformation change also alters the boiling point (10.94°F/ -11.7°C) and also the specificity.

The simple alkanes all are gaseous at room temperature and atmospheric pressure.  They are removed from crude oil before it is further processed, by simple heating.  The simplest is Methane, which is only on carbon and four hydrogen atoms, followed by Ethane with two carbons, Propane with three, and Butane with the four.

Pentane is the next simple alkane, the first to be liquid at room temperature and the first to have zero water solubility.  From Pentane on, the simple alkanes are named from the Greek alphabet, and are Hexane, Heptane, Octane, etc, on through the light naphthas, oils, waxes, and asphalts.

The formula for all simple alkanes, is the number of carbon atoms times two, plus two, because each carbon atom has four possible bonding sites.  A mnemonic device for remembering the first four alkanes, which were named before the Greek system was applied, is Mary Eats Peanut Butter.

After removal from the crude oil, the gases are typically de-sulfurized using steam and a catalytic reactive bed, and fractionally distilled into the four basic gases.  As fractional distilling separates the gasses by specific gravity, the principal contaminants in n-Butane at that point, will be Iso-Butane, a branched molecule isomer of n-Butane, as well as n-Propane, and Cyclo-Propane, plus low levels of heavier, longer chain molecules than C-4, and which are often referred to as Mystery Oil.

Neither of the butanes or propanes are particularly toxic at any sort of reasonable levels, nor is C-5 Pentane, but C-6 Hexane is and a third party forensic lab analysis of canned butane reveals the presence of molecules as long as c-18 as contaminates at the parts per billionth level.

We advise pre-distilling your butane to remove any mystery oil, prior to extraction.  It is easy to remove from the butane, but hard to remove from the concentrates afterwards. See /vacuum-distilling-butane/

MSDS info:

The following for instance is taken from a typical MSDS sheet for n-Butane. The Rat LD-50 (50% dead) is 658000 mg/m3 4 hours.  That is breathing a 65.8% pure butane atmosphere and asphixiating.

Section 11. Toxicological information for n-Butane; Diethyl; Freon 600; Liquefied petroleum gas; LPG; n-C4H10; Butanen; Butani; Methylethylmethane; UN 1011; UN 1075; A-17; Bu-Gas.

Specific effects

Carcinogenic effects No known significant effects or critical hazards.

Mutagenic effects No known significant effects or critical hazards.

Reproduction toxicity No known significant effects or critical hazards.

No specific information is available in our database regarding the other toxic effects of this material to humans.

Chronic effects on humans May cause damage to the following organs: central nervous system (CNS). Other toxic effects on humans

Toxicity data

Butane LC50 Inhalation Vapor

Rat 658000 mg/m3 4 hours

Product/ingredient name Result Species Dose Exposure

Products of degradation: carbon oxides (CO, CO2) and water.

Section 12. Ecological information

Products of degradation :

Environmental fate : Not available.

Environmental hazards : No known significant effects or critical hazards.

Toxicity to the environment : Not available.

Aquatic ecotoxicity Not available.

The MSDS LD-50s on Iso-Butane, Propane, Cyclo-Propane, and oleaginous waxes are as follows:

n-Propane; Dimethylmethane; Freon 290; Liquefied petroleum gas; Lpg; Propylhydride; R 290; C3H8; UN 1075; UN 1978; A-108; Hydrocarbon propellant. LC50 Inhalation Gas:  Rat >800000 ppm 15 minutes

Cyclopropnane; Trimethylene; Trimethylene (cyclic); UN 1027;  No LD-50 established;

Iso-Butane; 2-methyl-; Trimethylmethane; 1,1-Dimethylethane; 2-Methylpropane; isoC4H10; i-Butane; Isobutane mixtures; UN 1075; UN 1969; R 600a; tert-Butane; A 31;Methylpropane; Propane, 2-methyl-isobutane LC50 Inhalation Vapor Rat 658000 mg/m3 4 hours

Oleaginous Waxes- Paraffin, no notable toxicity or LD-50 available

n-Butane is used for any number of things, so it is processing beyond this point, or sharing storage tanks with other contaminated sources that may create health concerns.  While n-Butane is non-toxic enough used as a food propellant, if it is to be used as a stove fuel, it will in most cases have an odorant added for leak detection, as n-Butane has only a very light sweet petroleum odor.

Ethyl Mercap is most often added for that purpose, and is the familiar rotten egg smell is detectable at the astonishing low concentration of under 3 parts per Billionth!   Hexane (Gasoline) by comparison, has an odor threshold of around 30 parts per millionth, or about 10,000 times more is required for us to smell mercaptoethanol.

The MSDS for Ethyl Mercaptan shows 4420 ppm/4 hour(s) inhalation-rat LC50; 682 mg/kg oral-rat LD50, with the target organs being the central nervous system.  Not super toxic, but tastes and smells of rotten eggs, so that point may be mute.

Butadiene may be added to stove fuel as well, and is of serious concern.  While the following typical MSDS example shows relative low toxicity, take a look at the carcinogenic effects.

LD50 Oral Rat 5480 mg/kg -LC50 Inhalation Vapor Rat 285 g/m3 4 hours

LC50 Inhalation Vapor Rat 285000 mg/m3 4 hours

LC50 Inhalation Gas. Rat 128000 ppm 4 hours

Mutagenic effects No known significant effects or critical hazards.

Reproduction toxicity No known significant effects or critical hazards.

No specific information is available in our database regarding the other toxic effects of this material to humans.

CARCINOGENIC EFFECTS: Classified 1 (Proven for humans.) by IARC, 1 (Known to be human carcinogens.) by NTP, + (Proven.) by NIOSH, 1 (Proven for humans.) by European Union. Classified A2 (Suspected for humans.) by  ACGIH.

MUTAGENIC EFFECTS:  Classified 2 by European Union.

May cause damage to the following organs: the reproductive system, mucous membranes, upper respiratory tract, skin, eyes, central nervous system (CNS).

Here is another n and Isobutane toxicology division of the Texas Commission on Environmental Quality.

Of note, is that the FDA has rated n and Isobutane as GRAS, or Generally Recognized As Safe.

Food and Drug Administration, HHS

§ 184.1165 n-Butane and iso-butane.

(a) n-Butane and iso-butane (empirical formula C4H10, CAS Reg. Nos. 106– 97–8 and 75–28–5, respectively) are colorless, flammable gases at normal temperatures and pressures. They are easily liquefied under pressure at room temperature and are stored and shipped in the liquid state.

The butanes are obtained from natural gas by fractionation following absorption in oil, adsorption to surface-active agents, or refrigeration.

(b) The ingredients must be of a purity suitable for their intended use.

(c) In accordance with §184.1(b)(1), these ingredients are used in food with no limitations other than current good manufacturing practice. The affirmation of these ingredients as generally recognized as safe (GRAS) as direct human food ingredients is based upon the following current good manufacturing practice conditions of use:

(1) The ingredients are used as propellants, aerating agents, and gases as defined in § 170.3(o)(25) of this chapter.
(2) The ingredients are used in food at levels not to exceed current good manufacturing practice.
(d) Prior sanctions for these ingredients different from the uses established in this section do not exist or have been waived.

[48 FR 57270, Dec. 29, 1983, as amended at 73 FR 8607, Feb. 14, 2008; 76 FR 59249, Sept. 26, 2011]”

Lighter Butane: n-Butane may also be further refined to increase its purity, or to make it suitable for use in butane lighters.  R-600 Refrigerant and Instrument grade n-Butane are examples of higher purity n-Butane suitable for extractions, and are distributed by suppliers like Praxair and Airgas. As those sources are expensive and not usually available to non commercial customers, in support of federal guidelines listing it as a controlled substance used in the manufacture of illegal drugs, some folks use butane made for butane lighters.

Each manufacturers blend is slightly different, with n-Propane usually added as a propellant, because below the freezing temperature of water, butane is a liquid instead of a gas.

They also further refine the n-Butane to remove more of the low level "oleaginous waxes" aka Mystery Oil, which clog  the small orifices in expensive butane lighters.  This is often shown on lighter butane cans as a number followed by an X.  IE:  5X.

Here Madison Avenue has gotten a foot hold, and even 7X butane is available for even more money, though there is no advantage over a good 4X for the purpose of extraction.

One refiner has started labeling the brand names that they produce, Near Zero Impurities, guaranteeing under 50ppm impurities.  An independent test showed that they in fact are under 50 ppm, and even under the 15ppm testing cutoff, as were competitors brands not touting near zero impurities.

If using lighter butane, the safest course is to use tried and proven brands, but if forced to improvise, first obtain a MSDS sheet from that specific manufacturer, showing the contents.  Reject any containing mercaps or Butadiene.

Ingredients less than 1% need not be shown on the MSDS sheet, unless they present a health risk at the levels present, so they are not all inclusive, but a good place to start.

Here is a link to a study by Skyhighler ranking the different lighter butane brands by residual MO content:


Butane is highly flammable, so let us next talk about safety. First and foremost, always perform the extraction outside in a well ventilated area.  Have a fire extinguisher handy, as well as a blanket to roll up in, should the unthinkable happen.

It goes without saying that smoking around a butane extraction is asking for a disaster, but I have literally grabbed the hand of folks starting to light up because they “forgot” where they were at and what they were doing. May I suggest that you leave your lighter and smokes somewhere else when you are doing extractions.

Same with your cell phone!

Wear no synthetic fabrics, including your socks, because static electricity sparks probably ignite more butane unintentionally than bone headed smokers.

We use a fan to disperse the butane rapidly so as to keep it from pooling. Butane is heavier than air and will collect in low spots given its own devices. We use a plastic fan so that no sparks are created by a piece of gravel or other hard material passing through the fan blades.

In dry cold conditions, we add a grounding strap to our cans, so as to not draw static electricity sparks between the can and the column.

See /butane-safety/  for more butane safety detail.

Material Prep:

Material prep will of course depend on the application, so lets cover that subject generally.

Fresh buds should be dry of standing water and cut into small pieces, before being stuffed into a column and placed in a -32C/0F freezer for 48 hours to solidify.  Fresh frozen buds produce the most aromatic extraction.

Second best for for maximum terpene retention are buds broken up after 5 to 7 days hanging, or as soon as the small stems break freely.  They should be jarred immediately to retain freshness and run as soon as possible to prevent molding.

When extracting dried buds for vaporization, or bragging rights, the material is broken up just loosely enough to extract, but not enough to expose excessive broken cell boundaries.  That can be done by hand, or with a nugget buster.  Here is an example of a nug buster design that I scored off Roll It Up forum, but alas I can't remember the author:  The wire cloth can be obtained from Howard Wire at

Nug buster-1-1 Nug buster base-1-1

Buds for decarboxylation and most pristine appearance, should be placed on a cookie sheet and baked in a 94C/200F oven until just frangible, when rolled between the finger and thumb.  They can then be ground or scrubbed through a pasta strainer to remove the sticks and stems. Or ground up and should be jarred after grinding, to keep moisture pickup low.

The material shouldn't be bone dry as it will become too frangible, nor should a coffee grinder be used, because of the fines that it produces, that have to be subsequently removed.

We also dry our trim and leaves until frangible as above and scrub it through a pasta strainer, using a leather gloved hand and firm pressure, so as to minimize the amount of fine particles generated.

Another more commercial version is a cement mixer and dry ice chunks to break up the material for extraction.

So now that we have covered some of the basics, lets move on to the different processes:

Simple Flow Through Column:

Simple flow thorough columns are sometimes used in a technique called open blasting, and we once had a section covering that technique, we have elected to remove it because of the number of brothers and sisters blowing themselves and others up blasting indoors, despite our dire warnings and instructions to the contrary.

It is always the few, that ruin things for the us'n masses, but their actions paint us all with the same brush in the public eye.  If you have no alternative to open blasting, you can find ample instructions elsewhere on how to do so.


Butane is relatively easy to purge from cannabis oleoresins or concretes, as it has a boiling point of around -.5C/31.5F, or right about the freezing point of water.  Given enough time just sitting around, it will purge below our 5000 ppm smell sensory threshold, and even our far more acute sense of taste, either of which is a small percentage of the 658, 000 ppm, that the MSDS LD-50 tells us it took to asphyxiate 50% of the test rats in 4 hours.

We can speed up that purge, by using a dish with a large surface area, relative to the depth of the pool of oil.  Usually small extractions, so as to keep the depth thin, are the easiest to purge.

Air movement over the surface speeds up evaporation, by whisking away the saturated boundary layer and providing the extra energy for the molecules of butane to escape the surface of the oil.  Care must be exercised here, as any dust or lint in the air will end up in the oil, so usually a cheese cloth or similar porous cover is placed over it, before blowing over the top with a fan.

We can also speed it up with the application of heat.  Any heat will speed up the evaporation, and one line of thought is to keep the heat low and around 60C/140F, using a hot pad after the hot water bath.  A typical purge might take an hour and provides maximum terpene retention.

When adding bottom heat, you can also add a loose fitting lid, which will speed up the purging and keep out lint and dust.

For a faster purge, the temperature can be raised to above the melting point of the cannabis essential oils, or around 82C/180F, to give the butane molecules maximum mobility.

Instead of heat, vacuum may be applied to speed up the purge process.  That is the process that we use when we wish to maintain the cannabinoids in their carboxcylic acid forms.

In thin film vacuum purging, we place about an 3/16" of the oil in a 6" Pyrex Petri dish, and place that in a vacuum chamber, which also contains a hot plate.  That allows us to manipulate both the temperature and atmospheric pressure, so that we can achieve boiling at very low, or even ambient temperatures.

While we use 180F to vacuum purge a raw oleoresin, adding heat isn't necessary when thin film vacuum purging raw oleoresins redissolved in ethanol.  The alcohol will boil away under 28.5"Hg at ambient temperatures, as will the water that is left behind, even without adding any heat.

Vacuum ovens are the most popular way to purge anything more than a few grams of personal stash. This is a subject in and of itself and is covered in depth on our Purging in a Vacuum Oven page.

For our oral and topical meds, we exclusively used the bain marie collection vessel, and simply wiped the water off the outside, following the hot water purge, and set it in an electric fondue pot full of hot 121C/250F Canola oil.

The residual butane will boil off first, exiting in larger, multi sized bubbles, followed by the smaller equally sized CO2 bubbles from decarboxylation.

Depending on the use, we remove it from the hot oil when the bubble activity suddenly slacks dramatically off, indicating the 70% peak of the decarboxylation curve, or when it becomes quiescent, if we are looking for maximum sedative effect.


Hot oil Pots:

We use electric fondue pots for decarboxylation and I prefer the Quisinart, for their sensitive controls and narrow dead band.  We also have a couple of Rivals, which work well too, but whose controls aren't as sensitive.

Some fry cookers may have sensitive enough controls, but most are designed to primarily run at 375F, and lack control sensitivity, as well as have a large dead band at 250F.

It is important to make sure that the container is sitting on something that suspends it up off the bottom of the oil pot, to eliminate direct transfer hotspots. We keep several jar lid rings in the bottom of our electric fondue pots for that purpose.

We never trust any controls however, and use a good mercury lab thermometer, a digital, or an infra red optical pyrometer to establish and control temperatures.

Air stills such as the MegaHome essential oil or water distiller work great for purging or decarbing without the mess of a fondue pot. They also allow you to recapture the alcohol from a winterization step as well.

Thermos extraction:

Thermos extraction is an open extraction technique allowing an extended soak period at atmospheric pressure.

Because it is an open extraction process, and because of how many brothers and sisters are blowing themselves and others up, ignoring the warnings and open blasting indoors, we have removed instructions from this site.  

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  1. FishmanK

    From your experience and with hindsight, do you think a 6"x6" spool is enough collection chamber for a first extractor? Would getting a 6" by 10 or 12" collection chamber be worthwhile in versatility for the slightly higher cost?

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  2. Sam

    Is there any benefit or draw backs to blasting bho directly into 190 proof at room temp, then winterizing at sub 0 for 24-48hrs, filtering, heat evap, then thin film vac purge till done? Any thoughts on this process

    Reply       Edit
  3. jason

    I Just ordered the HeatVac XL heated Vacuum purge kit. First time user for this product, I'm hoping its nice. Long story short, I'm using all high grade buds that have been in the freezer for 24 to 48 hours. I'm blasting through a two foot glass extraction tube using about two ounces of product along with Stok butane. Ok, So here's my questions, the kit comes with a 5cfm 2 stage vacuum pump. With the amount of product I'm using, HOW MANY CANS OF BUTANE SHOULD I USE? HOW LONG DO I PURGE FOR? IS THERE ANY SPECIFIC SIGNS I SHOULD BE LOOKING FOR? And Last but not least, HOW DO I KNOW WHEN ALL THE BUTANE IS GONE? Someone PLEASE help me out? MASSIVE LOvE. ~SMiLES

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  4. beereighty

    Textures of your extracts:? do all your vaporizing extracts finish in a shatter or hard type state? Does Trim vs Flowers finish different? Or is all truly purged oil hard? Stretch snap consistency. Familiar with it? Is this a slightly un purged product? Or a "damp" un cured product? Do you find fresh flowers are harder to purge then say older trim? or is it it's water content that makes it seem softer longer? How long of a low temp purge (120f) is too long? and still never get to shatter? I've read it that slightly tacky extracts may have decarboxolized? but isn't your photo of the decarbed oil described as "flint" hard? I'm baffled by the variation I get in a seemingly identical process.

    Reply       Edit
  5. patrick

    Helo, I just have a couple questions. i have been keaping up with your page for some time now becuase the whole prosses facinats me and of cours i love wax. but i just started to do runs and so far it hasent been pritty the wax has been awsome though its a perfect amber goo. but back to my questions, iv ran two times with half Ounce and got pretty good resalts with both those runs lost some wax in the containers but not bad about two grams with blow through turky baster and in the small thermos run i got 3 grams but when i scaled up and ran 2 ounces through the blow through i only got 5 maby 6 grams do you think that becouse i ran it 3 seprat times onto the same pyrx and had hot water under it while i did all three runs i ran each tube with about 3/4 can butan till it ran clear each tube holds a littbit less than an once also i brake up the bud fine also in all the containers i notice alot of kief after run is this normal to and im realy trying to perfect this so i dont lose more

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  6. bongoognob

    Hey gray.. Running a closed loop system, an active one. Coming across residue.. Just trying to distill my CP n-tane. A tire smelling amber colored shit. I am running an appion with this system. Is it possible to pull this residue from the appion? Is my n tane from airgas just dirty? I've distilled it 3 times with the same residue. Now I'm runnig a passive recovery to see if it's still there. Thoughts, opinions?

    Reply       Edit
  7. Joe C

    Hi Skunk, Ive read in a few places before stumbling on your awesome site that dehydrating or putting bud in the oven before is better for BHO extraction... i plan to winterize but not decarboxylate as the end product will be vaporized... What are your thoughts on the drying pre extraction? & any other suggestions greatly apprecited !

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  8. C4h10

    Hello again GW I've been noticing that compared to others peoples concentrates mine seems to have less taste. I purge at about 105 for 12-24 hours (depending on size of the slab) and flip it once or twice during that time. I'm at just over 3000ft so my vac chamber only hits about -28. The bud I use is dry but not so dry that it turns to powder when broken up. I always hear that going low and slow makes for the best stuff but I'm almost wondering if the long purge is killing the taste? Would it be more affective to go higher temp for a shorter period of time? I don't think the buds are too dry but maybe. The concentrate looks amazing (see for your self here ) but I'm still not happy with the taste. Thanks for your time

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  9. Alex

    Plan on making my 1st run this weekend. I've read the forum from top to bottom but I still have questions, or maybe just need reassurance! I bought a Glass essential extractor 15-30 grams and plan on just making some for personal enjoyment. I live in FL so heat and humidity are an issue. I will outline the method I plan on employing along with any questions I have. Any and all feedback would be greatly approcated. 1) I have high quality flowers and I plan on breaking these up slightly, but not grinding them up like I would for regular consumption. These have been fully cured and I keep them vacumn packed in mason jars. Once packed in the extraction tube should I freeze before blasting? 2) I plan on blasting directly into a pyrex dish in a hot water bath until the butane has bubbled off sufficiently. 3) I then plan on transferring the extract to a Oil Slick DUO pad and heating on a hot plate or heating pad to diffuse the remaingin butane as I do not have a vacumn chamber. I want to use the final product in my vap. My question here is, what temp do I want to stay below in order to maximize the potency/effect? From what I gather it is 130-140 , is this accurate? Is this processed finished once the bubbles cease to develop or become less frequent? Is there adding vlaue to letting this air cure after the heated purge? Besides this basic outline I do have a couple of additional questions. Why do some of the videos that i've watched that detail this process end up with glass while others end up with a dryer more powdery sustbnace that i guess people call budder? Also I have a food saver and was thining of rigging up a vacumn of sorts using a mason jar and heat. Do you see any value in this? Finally, if I plan on vapping do I need to winterize or is this more of a personal preference? Sorry for the long post I juist dont want to ruin high quality flowers that took me a while to save up for!... Again any feedback is greatly appreciated!!!

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  10. beereighty a polypropylene cap with a silicone seal that screws onto mason jars, wide or regular, spill proof. works AWESOME for mason soaks, self filters to a decent degree for winterizers, use mesh if just purging. That link goes to the ebay sellers page for the caps. Stay safe

    Reply       Edit
  11. ommp pay it forward

    SKUNK PHARM RESEARCH, LLC IS NOW ON FACEBOOK. Join the Skunk Pharm and their friends today.

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  12. ThirstyMind

    What are the best practices, safety-wise, for thermos extractions? I'm thinking... - Since the system (thermos and butane) have been chilled, the butane enters the thermos as a liquid. This improves safety, right? It's less likely to explode during this step? - Static electricity is a big concern, where I live. I'm getting shocked all over the house right now. There are two critical moments I can think of: (1) when the butane can comes near the thermos during injection, and (2) after the soak, when pouring the butane from a metal thermos to a metal strainer/bain marie. How do I mitigate these concerns? - The most dangerous time seems to be when emptying the thermos after the soak, because the butane starts to boil off quickly. I will have a fan pointed at it (pushing not pulling). Anything else I should do, besides keep my distance until it's done? - How far should I be from possible ignition sources, outdoors? My back yard is pretty big, but not acres big. I know butane expands like 230:1, and is explosive at very low percentage, so is my entire big back yard made explosive by a 300ml can? For how long? Trying not to go all OCD on this, but I really don't want to blow up...

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  13. Elbretto

    Hello there, I have some questions regarding process in timing and temps. I have had trouble in the past in getting all the butane out and need help with purging. Using the double Pyrex boiler method blasting from a glass column, what is the best temperature to have the water at on initial blast? After the tane runs clear, I stop. But sometimes I blast again and see some green come out. What's the best way to ensure you are extracting the most oil possible? While letting the solution sit and purge, is it best to increase temp (if so, how high) or to let it stay the same? I do realize that time is all subjective, but when is it best to scrape or should I be agitating it frequently? I usually let it purge for a good two hours before collecting it and placing it on a slick pad, and purging again. Again, I want the butane all out, and unfortunately I can't afford a vacuum, so any more advice on purging techniques on how to make the best quality using hot water, toaster oven, lamp, etc will greatly be appreciated.

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  14. willbur

    so, this isn't related to bho but I was curios if water extraction takes out any plant waxes? just a thought I had thinking about all of those things being "water soluable."

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  15. emusic free trial this here

    Amazing things here. I am very satisfied to look your post. Thank you so much and I am having a look ahead to contact you. Will you please drop me a e-mail?

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  16. Bob

    Wow big props for putting all of this together, I wish I found this long ago when I was starting. Check out "RockBudder" or "Gold dust" also "powder toast", all random names for the same product.... but the 'River Rock' company is making it famous around CO. Someone please get the word out on how to make that product! it's waaaaaay better then all this 3-5% butane product thats flooded the market... its all dirty. JUST USE WATER PEOPLE!!! "Rockbudder" is the proof butane is for fools!

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      1. dwai

        Btw dispensaries have your product gcms tested first before they will buy least all the good ones do.....happy hunting :)

  17. Brandon Schilling

    Any thoughts about using a standard or over sized martini shaker as a dewar and blow into it while it's been chilled? Have it sitting in ice and/or packed with dry ice to allow a longer soak? I also considered punching the frozen butane can using a can opener then putting that into a vessel to pour into the dewar (proper terminology?) The reason I know you wouldn't want to do this directly is the pressure will spray plant matter everywhere. Forgive my beginners chemistry) sitting on a vibrating source to aid in a complete extraction without a repacked column. My goal in this method is to minimize the amount of waste. My only concern is having a lot of butane evaporate due to how slow it would be to get into the martini shaker? Just thought of this as it's pretty readily available, made of stainless, and has potential for modification. You could drill the holes like you'd done with the thermos to allow pressure release but then under the cap put a filter of choice to filter any mercaptans or particulate from the extract. I've also considered modifying the cap to a screw type system where you would screw the butane can to puncture but as soon as punctured the release will drip into the waiting solvent. As another potential option can you take the remains from the first wash and do a glycerine soak? To my understanding this would be a more sedative wash and may be useful for glycerine based vaporization.

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  18. thrag

    I use an empty rum bottle with 3 caps. 1 for injection 1 for extraction and 1 for straining. The injection cap has 2 holes. 1 in the center which is tapered for the nozzle fit, and 1 at the perimeter for pressure relief. The straining cap has a series of small holes drilled over the entire top and fitted with a coffee filter section. Everything (weed, bottle and gas) is frozen before starting. I simply fill the bottle 3/4 full of dry finely chopped weed and add butane until weed is covered. I then switch to the extraction cap which has been unaltered. This cap will prevent the butane from gassing off after it reaches its partial pressure equilibrium. I leave it sit for 20 minutes. I then CAREFULLY AND SLOWLY remove the cap from the bottle relieving the gas pressure that has built up, and place the filtering cap on the bottle and pour off into a pyrex bowl. Simple and cheap.

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  19. saucy steve

    I have a new hydrion scientific 1.9 cu.ft vac oven connected to an 8cfm robinair pump and have yet to produce quality results. Whenever I attempt to achieve a molten state it begins to wax up and taste's kind of nasty. The trim is sticky and loud but 2 months old. I dont pack the tubes to tight or grind the trim, i give the oil enough space to splay out in a film and I use a zero impurities brand of tane. I let it purge at 105 to 112 in a pie dish usually 20gs at a time over night in the oven no vacuum. In the morning when its achieved a 112 temp i vac it up. I'll usually crank it up to -32hg or -29.9. Any help would be greatly appreciated. Cheers M

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    1. Stephen

      Sounds like impurities during extraction. U say u allow room to let it film, assuming u open blast. More than likely humidity is fuckin ya. Hope it helps fellow Steve

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  20. Colomex510

    Nice feed bro... What u think of my tech? If u dntund reading bt I blast on to a little squared Pyrex waterbath at 120 f for 3 hours then I let it heat purge at 100 f for 48 hrs throw in to my chamber turn my vac on 29 ppm for 72hrs at 100 f n here's where I have Trouble it becomes very stable n I have hard time scraping off any suggestions?

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    1. skunkpharmresearch

      You will get better aromatics if you throw it in the vacuum chamber as soon as the visible butane is gone, at 115F and -29.5" Hg until the solvent bubbles cease. If you warm the dish up some, it will scrape easier.

      1. Colomex510

        Thanks bro for the feed back admire ur work yea it did aroma is fukin awsome ..thinking about winterizing bt not sure if it's really worth it dnt want to degrade it if I do it wrong

      2. Colomex510

        admire ur work yea it did aroma is fukin awsome ..thinking about winterizing bt not sure if it's really worth it dnt want to degrade it if I do it wrong

  21. Joshua

    Hello, first I must say how much I respect you for the quality of your information, as well as your willingness to educate everyone just for the sake of everyones happiness and well being. I have a questions regarding winterizaiton. Should it be done before or after a vac purge. My blasting normally goes as follows: I pack 10-12 grams of dehydrated whole buds into two tubes, and blow (I usually use Capital N-Butane or Purtane) through until it goes clear. I then unpack and allow to dry and use that material after breaking the buds up a little and then an extra 7-8 grams to fill a Oz tube and blow another can through until it runs clear. At this point the dish I've been blowing into has been kept at 130 f, i allow it to come down to 109 f, for a vac purge. I have 190 proof moonshine, should I dissolve into the 190 proof, or should I vac purge until no reaction and then dissolve into the 190. At the point when I ad the 190 proof, what is the best method to effectively filter without loosing any oil. to sum it up: What is the best process to winterize, And should it be done before or after a vac purge?

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  22. Eric

    So other than batch size and processing time are there other advantages to vac purging over open loop systems? I had thought that vac purging was the way to avoid winterizing but it looks like for Absolute I'll have to winterize either way yes? I've got an Omicron that I've yet to use (successfully anyway) that requires no plant material. Oh and Skunk Pharm is far and away the most comprehensive and helpful source I've found in the last 6 months of research so thanks for being awesome.

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  23. cory

    I've managed to purge to a shatter but can't seem to get it out of the pyrex vessel without it shattering into hash-dust. Any tricks to this? Prying/scraping tools? Temperatures? Perhaps my thin layer is too thin?

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      1. cory

        This works, but destroys the pristine glass-like appearance of the hash. Is there a good way to preserve the form it's purged in, or re-form it to be clear again? I have considered melting with more heat, but have been so careful to keep it from ever exceeding 120F up to this point. I don't want to decarb or lose any terpenes.

  24. Jon

    My friend uses these clear food grade (HDPE)plastic containers for ketchup and sauces I am convinced even though plastics claim food grade for the purpose he is using it there might be harmful things leeched from the plastic container I don't know if I am correct assuming this but I will only use glass

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  25. Gbroque

    So I did a sample run yesterday of the 1.5lb run I am doing tomorrow. The strain is GSC, I am running sugar trim that is much better than what passes for just trim, but not nearly as nice as the best sugar I've seen, and it's about 2.5 weeks old. Anyway. I loaded my extraction tube, a 12" x 1" ID, and gave it a go. My yield, though for such a small run it's not very accurate, was approximately .5g, which seemed low to me, then again, I didn't weigh my starting material. The bigger issue however, was the amount of contaminant that remained once I collected this small sample. Little bits of plant matter mostly, though they are small it was hard to tell. I used two unbleached coffee filters under a stainless steel 75 or 50 micron screen (not for added filtration, but to guard against a blowout). The next source I thought of, was the injection port on my extraction tube. But I really have no ideas about how all that contaminant got in the oil. Anyways. That's my story. I would appreciate it if you could tell me: What might have caused my yield to be so low? What could have been the source of the contaminant and how can I guard against that happening again? Also Should I be freezing my (unpacked into the extraction tube because I only have one) sugar trim? Thanks!

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  26. Ian

    Fantastic write up. Best I've come across. I've been experimenting with different techniques for a few years now, trying to find the ideal production method. Can't really claim I'm any closer to mastering it than I was a year ago, but it is entertaining. So, yesterday's bright (or dim) idea was; Put dry ice keif into a large whipped cream canister 1/3 - 2/5 full. Fill with butane to barely over half full. Seal the lid and after 10 minutes of soak time pressurize the canister with one NO² charge. And release the pressure another ten minutes later.... My thinking is based on an article I read on flash infused liquors. The pressure forces the alcohol through the cell walls of the material to be infused, when the pressure is released it escapes.. I decided not to attempt it until I talk to a chemist about possible reactions.. Any thoughts would be appreciated, thanks for writing this guide.

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  27. Chris

    Due to a static spark my butane collection pot caught fire . I have a lot! Of oil in it but I was forced to use a ABC fire extinguisher. Will I be able to recover my oil back? I was thinking maybe I can dissolve it in ethanol and try to drop it out of solution with cold? What is your idea? There's just no way? Or with effort and time yes

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  28. Aardvark

    Hey GW, thanks again for keeping this thread fresh, even after evolving on to the The Mk IVA Phoenix Terpenator. I am assembling my own closed system and decided to revisit back to the basics and see here that you recommend a column no larger than 1"; however, the Terpinator has a 4" capacity. Is the 1" column constraint only a factor when using the open system? AirGas quoted me $238 for 23.1 pounds of 99% N-Butane (plus $150 shipping & tank fee), but I also saw here that it is a controlled item, so it may be hard to obtain. What is the best way to "clean" the canned Colibri-type from cans? I already have a few lab-grade stainless tanks for reusing the Butane. Is there a carbon/silica cartridge I can use to filter out the water content as well as boiling off the Propane? Would an automotive refrigerant dryer cartridge help? Thanks!

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    1. skunkpharmresearch

      Yes, 1" ID is for a single pass open column. The Terpenators all have flooded columns. The best way I've found to remove the residual longer chain molecules from butane, is vacuum distillation. Propane actually works well in a Terpenator for extraction.

      1. Patients' 1st (@P1st_collective)

        its also from knowledge of purity levels that the more pure the butane, the more levels of propane it has. Propane plays a key part. Just look at the MSDS chart and you can see..

  29. Dr. SexPot

    Thank you Pharma-Wolf In your vast knowledge of canna/Chemistry what base product (method of extraction) should I be using for edibles that are geared towards recreational use? Conversely: what method (is it different then above) for a edible geared towards medicinal edables?

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  30. Lady Stiltz

    Ok just trying to get this right from the get go. I'm using fresh frozen bud in one run and the left over trim in another. Planning to use the thermos method, using the end product in an oil rig. Question is I plan to soak and dump twice into a Pyrex dish in a hot water bath. I want to winterize, so post bubble stopping do I then add the alcohol direct to the Pyrex? And do I need to do anything additional before throwing it in the vac purger to get rid of the alcohol or will the vac do that for me? Sorry that is where I am to get lost. Great information, thanks for helping keep everyone informed and safe!

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    1. skunkpharmresearch

      You can dump the alcohol in at that point, and we stick it in the freezer for 48 hours and filter out the waxes, before purging the alcohol. Check out winterization at

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