Glycerin Extraction

Kosher vegetable glycerin is an effective method for extracting cannabis concentrates directly from the plant material and produces a tasty medication that is easily ingested directly orally, or mixed with drinks and food.

Glycerin is a heavy, syrupy clear liquid sugar alcohol that has approximately 60% of the sweetness of sucrose, and about the same food value.

It is however not actually a true sugar and is often used as a sugar substitute, as diabetics are often able to use it without experienced the blood sugar rollercoaster they suffer with sucrose or other sugars.

Glycerin makes an extremely tasty and provocative cannabis tincture, that when made using cold extraction methods, is reminiscent of wild honey, as it preserves all the individual flavors, so that they dart off in all directions simultaneously.

Hot glycerin extraction also makes a tasty tincture, with the flavor more resembling a fine soup, where the individual flavors are married into one overall flavor. While not as whimsical and provocative as a cold extraction, it can be prepared start to finish in a couple days, where cold extractions take a minimum of 60 days and are commonly soaked for 120 days or longer.

Many of the provocative flavors and odors from cannabis are aromatic terpenes, and the reason that they are aromatic in the first place, is that they give off molecules at room temperature.

Heating speeds up the rate that the accompanying terpenoids and other aromatics are vaporized off, so many are collateral damage in a hot extraction and are lost.

The glycerin molecule is actually only a three carbon molecule chain, with three hydroxyl groups (OH) attached, and as hydroxyl groups are hydrophilic, glycerin is hygroscopic (absorbs water) and dissolves readily (miscible) in water.

It has a flash point of approximately 177C (351F), and a boiling point of 290 °C (554°F).

It is relatively non toxic. The MSDS tells us that the LD50 Oral rat dosage is 12,600 milligrams per kilogram of body weight, which is approximately 5.7 grams per pound of body weight, or 36 ounces for a 180 pound male.

By comparison, acute oral toxicity (LD50) Oral Rat for sucrose sugar is 29700 mg/kg and about 7060 mg/kg for ethyl (grain) alcohol.

At saturation, Glycerin only hold as 33% as much cannabis oil as the same volume of ethyl (grain) alcohol, so about three times more is required per dose.

To reach maximum saturation however, requires processing more than one batch of fresh material through the glycerin, because as the saturation level increases, the glycerin becomes less aggressive as a solvent and the partially dissolved cannabis boundary layer interface with the solvent is also no longer at full strength and as reactive.

To keep the reaction from slowing to a snails pace, or even stopping, some method must be used to keep removing this stagnant layer and refreshing the boundary between the solvent and resin.

In addition heat dramatically affects resin dissolution rates. The hotter it is, the faster it works, up to the point of overheating.

As glycerin is usually used as an oral med, we also need to consider decarboxylating the cannabinoids so that they are orally active.

If not in excess, some water solubles add to the flavor of a glycerin tincture, and taking all of the water out of the material before processing it, makes it frangible and prone to breaking into small fragments that may be hard to remove.

Let’s look at how these four variables can be manipulated to produce delicious and effective glycerin tinctures.

Drying and decarboxylation:

Plant material is typically dried to around 10/15% water content by weight for smoking and vaporizing purposes, which is low enough to make some delicious glycerin, but for those who prefer less water solubles in their glycerin tincture or wish to decarboxylate the material before extracting, you may add a drying and/or decarboxylation step.

To simply remove most of the remaining moisture, I place the plant material on a cookie sheet in a 200F oven and turn it, until it is frangible when I roll it between my finger and thumb.

At that point it is ready for extraction, but if you also wish to decarboxylate the plant material before making your tincture, you can then crank up the oven to 250F and after it stabilizes at the higher temperature, replace the plant material in the oven and hold it at temperature for approximately 30 minutes

That will add a roasted flavor to the tincture and many of the turpenoids will be lost, but it will decarboxylate approximately 70% of the existing carboxylic acids into their non acid orally active form.

An alternative to decarboxylating the material ahead of time, is to do it after the extraction is complete and the plant material has been filtered out. That eliminates the roasted flavor and preserves more of the turpennoids.

Using Temperature:

Elevating the temperature of the glycerin increases the rate of dissolution of the resins, especially if you raise the temperature high enough for the resins to be molten. THC, CBD and CBN are all molten at just under 180F, so we operate at that temperature.

The advantage of using as low a temperature as possible, is that fewer aromatic terpenoids are boiled off at that low a temperature, and it decarboxylates more slowly, so that the process doesn’t pass the peak of the decarboxylation curve and start down the other side toward low THC and high CBN. As previously noted, we can finish the decarboxylation later.

Keeping the boundary layer removed:

The boundary layer is the layer of partially reacted resin and dilute solvent that forms on the surface of the resin after the initial aggressive dissolution by the solvent. The solvent at that point is dilute, as is the resin concentration, so that the reaction slows or grinds to a halt.

To keep the reaction operating at a reasonable rate, we need to periodically or continuously remove that boundary layer, and there are four methods that I will present here.

The first is to stir. Simply stir gently and thoroughly with a wooden spoon

The second is to shake. Simply shake a jar of glycerin and plant material by hand regularly. A paint shaker would also work for this application.

The third is to tumble. Placing the jar of glycerin and plant material in a rock or photo film tumbler will keep the boundaries fresh. It is an effective and gentle way to speed up the process.

The forth is vibration. Placing jar of glycerin and plant material in a vibratory cartridge case cleaner, or other form of vibration, creates more shear energy that tumbling and will dissolve the material the fastest of any method we have tried thus far.

Material selection and preparation for hot or cold processing:

While glycerin tincture can be made from anything from prime bud to stems, it is tastiest done from prime bud and least tasty with the stems. I usually make glycerin tincture out of the sweet trim removed from the buds during manicuring and popcorn buds.

It is not necessary to grind up the material, only to break it up any buds so that the material is loose enough for the glycerin to reach all the surfaces. Excessive pulverization of the material will result in color and particulate pickup that is difficult to remove. If you leave some surfaces blinded however, the resins on those surfaces won’t be removed either.

Extracting using the cold process:

The cold process is the easiest and tastiest way to make glycerin tincture. We extract using the cold process, simply by soaking the plant material in glycerin at ambient temperatures and agitating it for sixty days or more. Sixty days is about the least amount of time for a cold extraction, and typically they are run 90 to over 120 days. I have one experiment with more than 365 days of soak time.

After the extended soak and agitation, the glycerin is poured off and pressed out of the plant material to yield quality and tasty tinctures. It can also be used with fresh material for another cycle, so as to build up more potency.

There are a number of ways to press out the glycerin from the plant material, and it applies to both cold and hot extraction, so I will cover that in a separate discussion at the end of extraction methods.

The way that we make cold process glycerin tincture, is to load a canning jar 2/3’ds full of plant material, lightly compacted and then cover with glycerin while stirring with a wooden spoon, until every surface is well coated and mixture is homogenous, and then add another inch of glycerin on top.

We place the jars in a cool dark place or cover to exclude light. We sometimes wrap jars with aluminum foil to exclude light.

Every day for the soak period days, we periodically agitate the jars, using one of the above methods and at the end I filter out the plant material for a a light golden to dark amber glycerin tincture, that is tasty and of high quality.

Because the aromatic terpenoids are preserved, it will have many flavors present, interacting and darting off in all directions simultaneously.

You can more easily filter the mixture if you warm it up to 150F or so before filtering.

Potency and gleaning:

As previously noted, to reach maximum saturation, requires processing more than one batch of fresh material through the glycerin, because as the saturation level increases, the glycerin becomes less aggressive as a solvent and the remaining partially dissolved cannabis is also no longer at full strength and as reactive.

In point of fact, the fresh pressed material from the above first cycle will still contain significant cannabinoids, which takes two to three cycles to get it all.

What we do is put the fresh pressed plant material back in the jar and refill with fresh glycerin and add fresh material to the freshly pressed glycerin for another cycle, if I desire more strength.

The fresh glycerin will do the best job of scavenging the remaining cannabinoids, and then can be used again with fresh material to further build up its potency. It is by this cascading technique, that we can leave little behind and yet still maintain quality and potency.

I should note that the most potent glycerin tincture is not necessarily the most tasty, and one cycle produces effective meds, so most of the time we do not bother to bump up the potency with cold tincture.

Hot glycerin extraction:

We prepare plant material and extract cannabis by the hot glycerin extraction process in much the same way as we do by the cold process, though we stir it instead of shaking, tumbling, or vibrating it.

We also use a thermal cycling process and stir regularly, rather than an extended cook as many processes call for. The expansion and contraction of the thermal cycling help break up the resins so that they dissolve more readily.

As with cold tincture, we load a canning jar 2/3’ds full of plant material, lightly compacted and then cover with glycerin while stirring with a wooden spoon, until every surface is well coated and mixture is homogenous, and then add another inch of glycerin on top.

We then set that jar in an electric fondue pot full of hot Canola oil at 200F, and stir it regularly with a wooden spoon until the mixture reaches 180F, and then we adjust the pot temperature controls to maintain 180F.

We stir the mixture regularly with a wooden spoon, for another thirty minutes, and then take it out of the hot oil and allow it to cool to ambient temperature.

For what it’s worth, we use a wooden spoon, because a light tink with a metal spoon against a hot glass jar while stirring, can break it and dump the whole mixture into the hot oil.

After the mixture has cooled to room temperature, we again place into 200F oil and bring it back up to 180F while stirring regularly. When it reaches 180F, after a through stir, we take it out of the hot oil and let it cool to ambient temperature again.

We repeat the last step about five more times and after the last cook and stir; we filter out the plant material while the mixture is still hot.

Filtering glycerin tincture:

Vegetable glycerin is thick and syrupy, so it doesn’t filter quickly or easily without mechanical help. The simplest way to filter it is to heat it up so that it isn’t so viscous, and pour it into a jelly bag, which you wring out by hand. That works, but leaves a lot of glycerin behind and you are limited to temperatures that you can handle with your hands.

A French coffee press, a potato ricer, or a jelly press can also work, and you can buy tincture presses used by the botanical extraction industry.

We made my own press, using a hydraulic bottle jack inside a scrap metal frame, which presses a filter bag between two stainless dog dishes, at a force of 12,000 psi, and catches the glycerin in a third stainless dog dish.

It presses the plant material into a hard little puck, that we have to break up to reprocess.

Flavoring glycerin tincture:

A well made glycerin tincture is a taste delight in its own right, but for those of ya’ll who just like to play, here is how we’ve flavored glycerin that I had already infused with cannabis oil.

We started by adding equal parts of Bing Cherry and Blueberry raisins in a blender with enough 190 proof grain alcohol to make a soupy paste when macerated by the blender.

We tossed in half as much Japanese Gari and a dash of Almond extract, added another half a cup of 190 proof, and let it blend well.

When pureed, we poured it into a stainless mixing cup and placed it in a 180F hot oil bath. We cooked and stirred it until all the alcohol was gone, and then removed it to cool.

We then put a bout two tablespoons of that concentrate into each 1/2 pint of infused glycerin to be flavored and place it in the 180F oil to cook for thirty minutes while stirring regularly.

At that point we remove it from the oil, filter out the concentrate using a filter bag and the glycerin press. The glycerin is delightfully flavored, and the chef gets to eat the concentrate from the filter bag! Ahwooooooooooooooooooooooooooooooo!!!!!!!!!! Hee, hee, hee………………..


Hot soak for one week; Hot cycle 7 times;Cold vibrate; Hot cycle and vibrate

Cold Vibrate                                                                               Density samples

Second pressing of material                                                160F cycled 7 times

Cold press 60 days                                                                   Hot versus cold extraction

339 responses to this post.

  1. Posted by Melanie Dunn on November 18, 2015 at 5:48 AM

    You have the density samples pictured with four test tubes ranging from clear to dark. What does this mean? How do I get this into vape form?


  2. No, that’s not true. THCA converts to THC over time as an oxidation process, even at room temperature but it takes time. This process requires decarboxylating the herb first, which converts THCA to THC, so regardless of the extraction method, you have a fully psychoactive product


  3. Posted by doug on November 5, 2015 at 12:48 PM

    Is it true that if you use a cold method that the THCA will not turn to THC and therefore
    will not be psychoactive


    • No, that’s not true. THCA converts to THC over time as an oxidation process, even at room temperature but it takes time. This process requires decarboxylating the herb first, which converts THCA to THC, so regardless of the extraction method, you have a fully psychoactive product


  4. Posted by Bruce Cartwright on October 2, 2015 at 8:13 PM

    So, what would happen if after completion of the first heating/cooling cycle, we put it in a Isi whip cream charger with a couple charges of NO2? Will this speed op the process? Would seem like a very nice way to make eJuice w/o going through oil extraction combined into a glycerin emulsion. Any thoughts?


  5. The highest concentration THC in glycerine I ever made was 3.6mg/ml, it is more usually at 1.8 to 2.4mg/ml range… Could adding lecithin or sucrose esters to VG menstrum increase the concentration of THC beyond 5mg/ml?


  6. Posted by damnsevern on September 17, 2015 at 3:42 PM

    Thank you for this information…Im wondering what the process would be to just extract the terpenes using VG. if possible I’m curious to see if I can add those terpenes back to my shatter x emulsifier solution for an e cig to give it more of a cannabis taste.


  7. You could: A. mix some high proof liquor with it and make a flavored tincture (for consumption purposes only, never vape alcohol)
    B. Try some on a drip atomizer with 40w+ capable battery. (VG only)
    C. Substitute the total volumn of your mix in cooking oil for some awesome edibles. 1 gram of extract should produce a noticeable body buzz.


  8. Posted by Hatti on September 13, 2015 at 5:36 PM

    I have a gram of bubble hash that has been sitting in vegetable glycerin for over a year now (18 months, maybe), and I’m wondering if it’s usable as vape juice. Should I strain it? Heat it? Use as is?


  9. how much makes a dose? I usually take a 15ml.


    • A dose varies by concentration, individual and medical condition.

      Since this is a glycerin extraction forum, I infer concentration to be around 33%. 15 mg X .3 = 5 mg active ingredient.

      We’ve found patients to vary considerably from a tolerance standpoint, but 5 mg would be a light dose.

      To find a persons tolerance, we typically start at 25 mg and titrate up in 4 hour increments, until we find their dosage.

      Dosage for pain, and for cancer are significantly different. A average tolerance pain dose might average 100 mg, while cancer patients work up to 333 mg doses, three times a day.


  10. Posted by dwebb19 on August 27, 2015 at 6:01 AM

    Cold I use a crock pot instead of the fondue Heater?


    • I would imagine you could use a crock pot, if it had the correct temperature and was relatively stable. The problem with most crock pots is that they usually only have settings like “low, med, high”. Fondue pots tend to have more precise temperature control due to the types of material it needs to heat, which have different requirements. They also tend to have more stable temperature maintenance


      • Posted by Tina on October 3, 2015 at 5:11 PM

        I used the crockpot, once the oil got to temp I put it on low while “cooking” and on warm to maintain during the cool down stage. I just finished it so I will get back to you on how it worked strength wise. this is also just the first round


  11. Posted by S2Vape on August 16, 2015 at 3:06 PM

    how much vegatble glycerin do i use for 10 grams of c02 oil so i can put in a vape cartridge


  12. I always enjoy reading your articles and this one is no exception. I like the mix of science and practicality you use, that us lay persons can understand and utilize. I was thinking of a possible variation on this and I was wondering if you could provide some insight.

    My primary goal is to produce an e-cig juice. Since THC vaporizes between 355-385F, could you heat VG to a temperature in that range and give the bud a wash, vaporizing the THC? The resulting vapor would then be readily taken into the VG in solution. If this could work, then I would imagine that you could realize potency close to the max solubility of VG at 33% no? If precautions are made to prevent escaping vapor, could this not also capture a lot of the terpenes, preserving the taste and aroma of the original bud? Again, I don’t know if this would work, but if it did, it would be a very quick way of producing a potent VG tincture, without requiring decarb or having to worry about the boundary layer.

    I am anxious to hear your thoughts on this.


  13. Im currently prepping for production stage with the finest 190 bubble hash homogenized with VG. This is the “meltdown” # so i forecast a (hopefully) viscose mixture @150 then sustaining @ RT?. Hate to see it go but the biotechnology must persevere at any cost. I thank the efforts of the GW gang n collective folks for giving me the opportunity to self educate for the right reasons.

    BTW check out the Co2 washing machine…. thoughts team?

    jolly o


  14. Posted by Gary Daktyl on July 14, 2015 at 11:04 PM

    Have you experimented with adding keif or bubble hash to vg? Also curious if you have had any of your results tested in the lab? And, thank you for the great info!


  15. Posted by Mario Brisson on July 4, 2015 at 2:24 AM

    Don’t waste the grinds in the filter bag yo! You re-steep that mash in coconut oil to make medicinal salve :D


  16. Posted by Scottthestoner on June 28, 2015 at 9:47 PM

    Why boil it in oil and not water??


  17. […] Tea has been my favorite daily beverage other than the evening Tidy. I can drink it cold and hot while it is sweet or not. What bothered me about Tea was when it was cold and unsweetened; you could not dissolve any sugar to make it sweet while it is already cold. This is when I would use artificial powder sweetener because it will dissolve while it is cold. Science explains this state of a liquid matter as Supersaturated. Temperature is what controls how much dissolves in a liquid unless that compound dissolves based on a process called Half-Life. Then to make it more confusing, compounds are either dissolve in water or oil. When making Cannabis Tea, all of these facts come into play and my goal is to explain it in a way that is understood. We will then review different Cannabis Tea recipes and their expected outcomes. Here in lies the confusion for making a Cannabis Tea by trying to dissolve Cannabis, which is Oil Soluble in water. All is not lost, we have to introduce another ingredient to help it dissolve or mix with the water. This ingredient will work as a carrier or emulsifier for the Cannabis that will mix with the water. Oil, Butter, or Glycerin will work as the new ingredient. I can see your expression on your face right now and it is not good. Oil or Butter has been added to Tea and Coffee a lot and it is called “Bulletproof” because of the energy boost. Or you can use Glycerin which is a heavy, syrupy clear liquid sugar alcohol that has approximately 60% of the sweetness of sucrose, and about the same food value. All is not lost for making Cannabis Tea if you want it another way. Trying to place your Cannabis in boiling water like regular Tea is not an efficient or tasty method. For the best taste without wasting your Cannabis you would need it in an Extract form like Kief, Hashish, Tincture, Wax, Simpson Oil, etc. We will review a very simple Cannabis Tea recipe with this Post. I suggest that before you use this recipe, read the “Cannabis Cooking Guidelines”. If you plan on using infused Oil, Butter, or Glycerin; you will need to read “Cannabis Cooking Oil / Butter” for the Cannabis infusion process. Brew your Tea the way you would normally make it. While the Tea is still hot (Above 180° F) and the Tea bags have been removed, mix in your form of Cannabis that you have chosen. Always start with small quantities until you have determined your preferred strength. Once the Cannabis has been mixed with the Tea, it can be cooled down for drinking. The Tea can also be drank while it is hot like coffee. Keep the Cannabis Tea well mixed while drinking because it is not dissolved in the water it is being suspended in the water. This can also be used for mixing in your Coffee or any other hot beverage. Please enjoy and remember to start with small concentrations and work your way up to your desired strength. Thanks, K Lee References: […]


  18. Posted by ackris on June 10, 2015 at 10:04 AM


    Good day sir. I am curious about the difference between using vegetable glycerin vs USP glycerin (anhydrous) 99.5%. USP was recommended for emulsification from a phd senior chemist friend but my attempts to properly emulsify for atomization has left much to be desired. Any insight would be much appreciated.



  19. How about making this with oil instead of plant material? how much per 30ml could be put into it?


    • Posted by RunningTree on June 22, 2015 at 8:45 PM

      In my experience, hydrocarbon extracted Oil does not like to bind with, or stay in solution for any period of time in, Vegetable Glycerin even after being heated to, and homogenized in, a full but reasonable scale of temperatures. Time after time it simply seems to fall back out of solution.


      • What we’ve found is that VG is more selective than either butane or ethanol, so everything that they extract, won’t dissolve or stay in solution with VG. It just absorbs what it likes and rejects the rest, to float around in little hard to remove globules.


        • Posted by WeedScientist on July 24, 2015 at 2:48 PM

          Do you think that VG is ‘more selective’ than butane or ethanol, and those extracts which are very high in cannabinoids won’t dissolve in VG because VG is actually an extremely poor solvent for cannabinoids? Have you had tincture made with the above processes analyzed for cannabinoid concentration? What are those results?


          • One of the biggest issues using VG for extraction, is that not only is it more selective, but it can’t easily be concentrated through reduction afterwards, like alcohol and butane can. It will saturate at maybe 20%, while by removing most of the alcohol or butane, we can concentrate close to 100%, putting the extracted cannabinoids in the high 90%’S.

  20. Posted by dj on May 19, 2015 at 1:17 AM

    Do you still decarboxylate with the hot extraction method?


  21. Posted by Raymond Comley on April 19, 2015 at 2:24 AM

    Hey Guys, After reading this awesome article i just wanted to get one thing straight. To avoid decarboxylating my weed beforehand because i hate the roasted taste and just drying it out a little in the oven then placing it in the jar for the hot extraction. Will it be fully decarboxylated at the end or … should i strain out the herbs, heat it in the oil to the higher temp (?) for (?) minutes to be sure? Thanks alot ❤❤❤


  22. Posted by AshinKushin on April 15, 2015 at 1:47 AM

    I’m trying to get high fool


  23. Also I was wondering what your thoughts on agitating with an ultra sonic cleaner would be. When I make diy e liquid for e cigs generally people need to allow it to steep for XX amount of days….. shaking a few minutes a day. Some of us find using a ultra sonic cleaner reduces a weeks worth of steeping to just a few cycles. I’m wondering if a UC would help speed up a cold VG tincture process as well.


  24. If I were to do a VG tincture based on primo material, would it be less potent, as potent, or more potent than as if I were to vaporize or combust the same primo raw material?


    • Posted by sam prater on April 14, 2015 at 11:03 AM

      Eating it is much more effective for pain and other things. Some of us are really sick and it helps a lot. Some folks are just getting high. i, personally, do not approve of the legalization of MJ for other than medical purposes!


      • Posted by Dustey on June 12, 2015 at 2:31 AM

        He says with a beer in his hand.


      • Posted by Yum on May 14, 2015 at 2:58 AM

        Prevention is better than the Pharma cure. Take it before you get sick. I personally do not approve of foolish legislation talk.


      • Posted by T.J. on June 1, 2015 at 4:56 PM

        When it’s legal for recreation and medical, the medical uses will get it much cheaper and they will not be looked at as fakers. Why take an illness for a medication when the medication is legal over the counter? So, as a potential medical user in an area where it’s illegal for both medical and recreation, I say – who cares if stoners get it to? Don’t be so judgemental. Also a plus – people are less likely to be drinks when they are also stoners, so we will be less likely killed in dui accidents. When it’s legal for recreation in more areas, (it will be more acceptable) strict states like the biblebelts will be more lenient for medical use.


  25. Posted by Carmen Copper on March 17, 2015 at 11:19 AM

    Great info!!!!!!!very direct and to the point


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