Decarboxylation

Cannabis produces phyto cannabinoids in a carboxylic acid form that are not orally active at least at the CB-1 receptor sites, because they don’t readily pass the blood brain barrier in their polar form.

To enable them to pass the blood brain barrier, they must first be decarboxylated, to remove the COOH carboxyl group of atoms, which exits in the form of H20 and CO2.

Decarboxylation occurs naturally with time and temperature, as a function of drying, but we can shorten the amount of time required considerably, by adding more heat.  The more heat, the faster it occurs, within reasonable ranges, and in fact occurs spontaneously when the material is burned or vaporized.

There is another mechanism at play however, which suggests that we need to control the decarboxylation temperatures carefully.

When we heat cannabis to convert the THCA and CBDA into THC and CBD, we are also converting THC to CBN at a faster rate.  At about 70% decarboxylation, we actually start converting THC to CBN at a faster rate than we are converting THCA to THC, so as you can see by the following graph, after about 70% decarboxylation, the levels of THC actually start to fall sharply.

That of course means that the CBN also begins to rise and the medication is becoming more sedative.

Thank you Jump 117 for this excellent graph!

Decarboxylation Graph-1-1

Decarboxylation graph

Another fly in the ointment, is that we can never know for sure exactly what the starting state of decarboxylation is, so the times at temperature shown on the graphs are an average.

We can’t expect dry material placed in an oven at any given temperature to be that uniform temperature throughout instantly upon placing it in a heated oven, nor know for sure the state of decarboxylation by simple observation.

Decarboxylating plant material, also alters the taste (roasted/toasted), which some find less agreeable, and of course decarboxylating also evaporates away the smaller Monoterpenes and Sequiterpenes alcohols, phenols, ketones, aldehydes, ethers, and esters.

The good news is that it is dirt simple to monitor the state of cannabis oil decarboxylation placed in a 121C/250F hot oil bath, because you can watch the CO2 bubble production.

Just like the curves suggest, CO2 bubble production will proceed at its own observable rate. By keeping the puddle of oil lightly stirred on the bottom and in the corners of the pot (I use a bamboo skewer), so as to keep the bubbles broken free and floating to the top, you can tell exactly when the bubble formation suddenly tapers off at the top of the curve.

That is the point that we take it out of the oil for maximum head effect, and we leave it in until all bubbling stops, if we want a more sedative night time med.

Here are a couple pictures of what oil looks like when boiling off the residual butane.  Residual butane or alcohol produces larger, randomly sized bubbles, and is fully purged, when they cease.

I am seemingly missing the middle picture of the CO2 bubbles, so I will add it later, but the second picture shows what fully decarboxylated oil looks like.

Residual solvent bubbles above:

Quiescent oil.

728 responses to this post.

  1. Coconut oil has a higher fat content, better extraction.

    Reply

  2. Posted by Mike on March 20, 2017 at 5:01 PM

    So I should decarb a gram of oil in my oven at 250f for 25 minutes? My recipe calls for butter but I see coconut oil mentioned here quite a bit. What is the reason for this? Should I substitute half coconut oil?

    Reply

  3. Was wondering how long it takes to Decarb naturally?

    Reply

    • Posted by zack membrino on March 16, 2017 at 5:57 AM

      Cannabis Decarbs naturally when being cured or dried, This step takes around 3 weeks, for proper drying and curing. But at this point you still need additional heat or time for it to actually decarb for edibles.

      Reply

    • Sea Maiden ages her glycerine extractions a year to naturally decarboxylate them. Clearly it would depend on the storage conditions.

      GW

      Reply

  4. Posted by daveed78 on March 9, 2017 at 4:50 PM

    I’m going to be decarbing ~8g oz total of shatter and budder in the oven, what temperature should I use and how long (not using the oil method you suggested)? Afterwards I’m going to infuse it into coconut oil over a double boiler. I did the math and I have ~6400mg of thc to work with ideally so at 40mg a cookie I’m hoping to get around 160 cookies. How much coconut oil should I use and how long should I let it infuse for? Also how much lecithin should I add?

    Reply

  5. Posted by Sweetleaf Joe on March 6, 2017 at 7:03 PM

    Can you decarboxylate a thc-a tincture? If so, how?

    Reply

    • Depends on the boiling point of the solvent the THC-a is a solute in. Easy with oil or VG, but not so easy in alcohol because of the low boiling point.

      Stick a container of it 250F vegetable oil for approximately 30 minutes, but you can gauge it precisely by watching CO2 bubble production, as described in the article,

      GW

      Reply

    • Posted by Mike on March 10, 2017 at 12:28 PM

      Put it in oven at 330 (whole jar an all) leave it for a hr…half that time is the jars coming up to temp

      Reply

  6. Posted by kurt on March 5, 2017 at 12:10 PM

    Do the times change if you heat coconut oil to 250-275 and decarb the BHO oil in the coconut oil

    Reply

  7. Posted by Dustin S on March 5, 2017 at 11:48 AM

    If I am going to be making things likes brownies, cookies, and such. Would I need to decarb the bho before if it’s going to be in an 325-375 degree fahrenheit oven for 20-30 minutes? I feel that it will decarb as it cooks, and have had varying different effects from everything I’ve made.

    Reply

    • The center of the brownies won’t be reaching 375 until the end, so it will help but probably won’t do a complete job.

      On the other hand, we made brownies that work for decades before having decarboxylation explained to us, and they worked, demonstrating that it works at least somewhat, if not perfectly.

      GW

      Reply

      • Posted by Dustin S on March 6, 2017 at 5:07 AM

        Thank you for all the info! Also I made made some medicated gummy bears yesterday, and the gummy bears I made with bho have completely melted into a red puddle in a ziplock overnight while the ones without are completely fine. I tried to find something on the internet for a couple hours but haven’t come across anything. I made hard candy the same way and had no problem with the wax dissolving into the sugar mixture but these just have little pieces of wax in them and on the outside. Would you have any info on the making of gummies? Would I need to use a tincture to incorporate the bho first? Much appreciated skunkpharm you people rock!

        Reply

  8. Posted by Dustin Solano on February 27, 2017 at 8:33 AM

    I’m wanting to make a THC-A tincture using BHO. Do I still need to decarb my concentrates before infusing with oil?

    Reply

    • Is a THC-a tincture the desired end product? What is your desired end use?

      A THC-a tincture is ostensibly the THC-a, which is not decarboxylated, mixed with the solvent which doesn’t need to be, nor can it be.

      The THC-a molecule is too large to pass the blood brain barrier so as to reach the CB-1 receptors in the brain, so won’t be psychoactive.

      If you decarboxylate the C-22 THC-a, it will revert to its phenolic diterpenoid C-21 form, which would be THC. It will pass the blood brain barrier and produce psychoactive effects.

      A THC-a tincture must be carefully stored and used fast, because it is unstable and may (will) decarboxylate with time or under certain conditions, thus producing psychoactive effects and making previous dosage calculations moot.

      GW

      Reply

      • Posted by Dustin Solano on February 28, 2017 at 8:44 AM

        Thank you for your response. Yes, a THC-a tincture is the desired end product and will be administered orally for my dog. I had purchased a THC-a tincture from my local dispensary for him that I gave along with an Everclear extract that has cleared a diagnosed osteosarcoma cancer. I’d like to keep using the combination of the two for continued maintenance. The tincture is stored in the fridge to help prevent or prolong activation.

        Reply

      • Posted by Dustin Solano on February 28, 2017 at 9:31 AM

        My plan is to use a Magic Butter machine to infuse the oil. I was going to run multiple cycles. One at 130° for 2-4hrs to blend then a couple 8hrs cycles with no heat to finalize.

        Reply

    • Posted by Darby on February 28, 2017 at 7:32 PM

      If you want thc-a you MUST NOT decarboxylate and should use as little heat as possible. Kept refrigerated I have had it remain decarboxylated for over three months. As it decarboxylates gradually either you or your dog would have the opportunity to become used to it gradually.

      Reply

      • Posted by Dustin Solano on February 28, 2017 at 8:36 PM

        Thank you so so much. Your response and information has been and will be incredibly useful. I appreciate you taking the time to help and for your continued research and education in cannabis.

        Reply

  9. Posted by Trev on February 23, 2017 at 11:11 AM

    Hey I’m decarbing some raw hash oil it’s been in the oven for about a hour now and there is no sign of bubbling what you thing is the problem.

    Reply

  10. Posted by amber on February 16, 2017 at 12:10 PM

    Can I decarboxylate raw hash oil in a conventional oven? if so, what temp an for how long? Also, does decarbing raw oil release dangerous fumes i should be careful of?

    Reply

    • You can decarboxylate in a conventional oven using the approximate time show on the chart, and can tell where you’re at, by watching the bubbles.

      The CO2 and H2O bubbles released are non toxic and non flammable.

      GW

      Reply

  11. Posted by Tea Pea on February 7, 2017 at 8:04 AM

    Just wondering why you chose to go with 250 instead of 290?
    Is it because it’s easier to gauge when the CO2 bubbles slow down… due to the length of time (7 vs 27 min) and thus easier not to over do it?

    Reply

  12. Posted by lisa ableitner on January 26, 2017 at 6:00 PM

    How long long do u leave it steep in 250degree oil which is in another container (double boiler)

    Reply

    • Depends on what level of decarboxylation I am shooting for, but I tell by watching the CO2 bubbles produced to tell exactly where I am in the process. Generally at 250F, it takes in the neighborhood of 30 minutes to hit 70%, which is where I usually stop.

      Check the graph demonstrating rates at different temperatures.

      GW

      Reply

  13. Posted by Maia Hughes on January 25, 2017 at 9:20 AM

    How do you set up a hot oil bath. I have 2 grams of wax that I need to decarb for edibles, I will be wanting to make it into coconut oil. This is my first time and really don’t want to mess it up.
    Thank you!

    Reply

    • I found a good quality fondue pot to be a good way to make and maintain an oil pot. They are typically accurate at the ranges we operate in, where hot oil cookers like the Fry Daddy are really meant to operate closer to 375F.

      We used a Quissanart, but have also used a Revel, and just fill them with canola oil and heat them to 250F. Set a bain marie or other stainless container of oil in the bath to heat. Be careful and make sure it can’t turn over if it floats in the bath.

      GW

      Reply

  14. Posted by Ja gab on December 31, 2016 at 6:53 AM

    Aloha Bro
    When making cannabis oil from Rozen what is the mixture or milligrams of marijuana to Vg for vapor pen oil,,
    Maholo

    Reply

  15. Posted by Darby on December 23, 2016 at 9:01 AM

    Don’t put it directly into the oil bath unless you want a very weak oil tincture, it will dissolve into the oil and you will not get it out. Place it in another container and that sits in the oil bath, you are making a double boiler.

    Reply

  16. Posted by Lloyd E Songer on December 22, 2016 at 2:41 AM

    Hi. My question is this when doing a BHO. After purging in the vacuum oven. Can you decarboxylate before you do your dewax to put it through a short path distillation unit with a cold trap to capture the ethanol?

    Reply

  17. Posted by Blue kangaroo on December 19, 2016 at 8:48 PM

    CBDA to CBD Decarboxylation is slightly different. From what I understand, it happens at 266 F (176 – 275) for 60 minutes

    Reply

    • Posted by lisa ableitner on January 26, 2017 at 6:01 PM

      Oops – I found th answer😬 Thank you. Any other tips will be greatly appreciated. Thank you again

      Reply

  18. I had no idea that butane honey oil extraction is the most clean method of extraction of cannabis. It is interesting that butane extraction is so effective because of it’s nonexistent level of polarity. Many people may be attracted to butane honey oil extraction because of the potential health benefits available with the use of natural and essential oils.

    Reply

  19. Posted by WAXMAN on December 13, 2016 at 11:22 PM

    CAN I decarb. wax alone without any other additions ie: coconut oil?

    Reply

  20. Posted by James kelly O"Reilly on December 13, 2016 at 11:01 PM

    when measuring decarbed BHO ( with the 1 to 1 coconut oil ) BHO is 78% without coconut .what is the recipe for 100 mg per gummy. How much 1 to 1 BHO do I put in? thanks.

    Reply

    • 100 mg/.78 = 128 mg required per 100mg dose.

      Weight of gummy bear minus 128 mg equivalent concentrate dose = candy weight in recipe

      GW

      Reply

      • Posted by Nick on December 15, 2016 at 3:30 PM

        GW- He says it is 1:1 with coconut oil. So, the 1:1 is the formula becomes 100/(.78/2) = 256 mg for a 100 mg dose.

        Although that seems like a rather strong dose for a gummy bear. It is so difficult to just eat one. 😉

        Reply

        • Posted by Al Khemi on December 15, 2016 at 6:44 PM

          Man, this is like “Lifestyles of the Stoned and Secretive”…personally, it sounds like y’all live in the growers’ laps – can’t imagine what would be possible with access like that..SALUT, y’all – that’s one hell of a gig!

          Reply

        • My bad, I was looking it as a 78% THC concentrate. If it is 50/50 with coconut oil, it would have to be doubled.

          I’ve never made gummy bears, but I have lollypops, and didn’t need any coconut oil.

          100 mg is about one full dose for an average person, and it is hard to eat just one gummy bear, versus a hand full. Carla’s Truffles consistently OD folks who couldn’t settle for just one, so we stopped making medibles.

          In WA they limit one dose to 10 mg THC, and up to 10 doses per package………………

          Reply

          • Posted by Living for now on February 21, 2017 at 11:12 PM

            Ya the 10mg is bullshit… I do 1.5 grams of 92 and up shatter… yes it’s under 10 a gram but ya grow up with friends they grow since kids and u develop an autoimmune disease that attacks ur brain and spin ya they treat ya for almost free in Idaho but I am the first 4oad into Idaho on the wa and Id border…

  21. […] You can always use an instant-read digital cooking thermometer for more exact measurements. This article shows the time/temperature curve for decarbing cannabis and offers some other useful thoughts on the […]

    Reply

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