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.

404 responses to this post.

  1. Dear friend, correct me if I am wrong but I think 145C curve is wrong. Brownies and cookies are cooked at 150C for much longer than and they are super powerful (high on THC) and not sedative (low on CBN) …

    Also, as you can see in graphic “Figure 1: (A)” in the link below, after decarboxylating cannabis in an oven for 30 min @ 145C, THC is at its highest and CBN very low… so, which graphic is correct my friend?

    “Figure 1: (A)… Further conversion of THC into its’ main degradation product cannabinol (CBN) only took place to a small degree during the oven treatment (30 min @ 145C).”

    thanks and cheers from Mexico City


    • Posted by figgernaggot on March 16, 2015 at 9:30 PM

      i should think it fairly obvious that brownie batter is much more insulatory than n-hexane.

      also there is no scientific pharmacological literature (Afaik) that indicates CBN as having sedative effects


  2. I can chime in here. First thing is ,, is that if anyone wants to know how much THC,THC-A THCV, THCVA Or any other cannabanoid decarb effect ,exactly just get it tested by an HPLC test lab. It may cost 100$ but It can be done for more like 50$ from the right lab. HPLC testing is the ONLY way to know for sure. Gas testing will not be acurate ,since the product is being heated as it is being tested. Use the HPLC test. I study this stuff many hours every day. Want to see it for your selfs ? Just go to SC LABS Their in Capatollia Ca. I dont remember if they are a .com or a .org. Later I think. well then click on tested on the top of the page. If you click on a sampel ,its whole test will pop up and you can see its cannabanoid values. Oil, HASH, flowers, wax, Shatter. whatever.Most cannabis is raw with THC-A high. If delt with cold it will stay high in THC-A ie. yellow WAXES. and I say MOST flowers becouse their are some that may have say,, 7% THC whitch is enough to get a novis high. or maybe even me. in the raw form. Check the page and learn. Glenn—


  3. Posted by MattMatt on March 12, 2015 at 4:19 PM

    No, the temps needed to infuse the cannabinoids in various fats, butters and oils is way below what is needed to decarb. In fact given enough time you can do this infusion with virtually no heat and avoid all decarboxylation and make an infused product that is almost entirely raw cannabinoid acids (which is desired for some people and some conditions). If you are planning to infuse cannabis into butter then prior decarb is a good idea


  4. Posted by MattMatt on March 1, 2015 at 1:11 PM

    If I may address your second point first, if you are going to cook at 350F for 25 minutes then prior decarb is unnecessary. Generally that temp is too hot as THC can and will vaporise at that temp, but inside a brownie mix it may well struggle to escape so the decarb data on the graph would not apply perfectly to brownies or cake mix.
    there are two things to consider when cooking above the optimum temps. Above 140c (145c for example) is still too low to vaporise THC (which begins at 157c) but it will degrade it to CBN at a fast rate (which is what accounts for the THC drop shown on the graph) at those temps if applied for too long. Above 157c you will begin to vaporise THC (though how long to vaporise it all off is hard to say and depends on other factors).
    As I said, vaporising is not so devastating when dealing with cake or brownies mixes as the THC gets trapped even if vaporised so does not actually escape. Also vaporising THCA will decarb it instantly with out necessarily degrading it to CBN and even if it does CBN is also psychoactive, though slightly less than THC, and very sedative so will make edibles feel strong, especially from a sedative point of view.
    That being said I would like more than this one graph to guide us regarding decarb and would like to see more test results of decarb in different forms (oil, hash, weed, edibles etc.). Not just to verify these results (which can differ depending on other factors)but also to expand on them. The graph supports the optimum decarb temp for with in 40 minutes to be about 120c (between 110c to 130c) but gives very little data on other temps outside of the 50 minute time frame. People can decarb at 80c, or 60c but how long such temps require is hard to say


    • Posted by sidk on March 1, 2015 at 1:50 PM

      Ok, I had not considered what the actual inside temp might be. I have a thermocouple meter with a type-K probe I can use to take some interior temps at various times and locations. I’ll bake some straight brownies tonite and take some data.
      More when I know more…


      • Posted by spartan on March 11, 2015 at 11:37 AM

        Internal temperature of any baked good should never exceed 212 F for the simple reason that if it’s hotter than that all the water has evaporated away and you’re left with crackers, not brownies.


    • Posted by sidk on March 2, 2015 at 3:32 PM

      How can I post (upload) a jpg showing temperature data??


    • Posted by sidk on March 4, 2015 at 11:58 AM

      I did not phrase the question correctly…
      I have temperature data from a brownie bake. I have a graph showing the data but I need help on how to upload the jpg file to you.


    • Posted by Alex Taylor on March 12, 2015 at 11:05 AM

      I am curious about the process of not decarbing when you plan to bake in the oven at 350 degrees F anyway. If there is no initial decarbing, then when you are infusing something like butter or oil prior to baking, do the trim and butter need to combine at a certain temp in order to remove the cannabinoids from the trim into the butter? Obviously the butter needs to be properly infused before incorporating into a batter to then be baked. Thanks!


  5. Posted by MattMatt on March 1, 2015 at 8:03 AM

    Out of interest where did you get that text?


  6. Posted by tavon on February 28, 2015 at 9:05 AM

    Decarboxylation – When making cannabis oil for treating late stage cancer it is important to understand decarboxylation. Cannabis in raw/unheated form is primarily THCA, which converts to active THC through heat and time. While some very slow and gradual decarboxylation does occur at temperatures as low as room temp during drying and curing stages of weed preparation it is not until higher heats are encountered that all THCA is converted to THC. If you are making cannabis oil you need to make sure the oil is cooked sufficiently to complete full decarb. Raw cannabis is very beneficial and cannabinoid acids like THCA, along with naturally present terpenes, are believed to be very beneficial with possible anti cancer properties. However, it is active THC, and CBD, that has the majority of clinical and anecdotal evidence supporting its cancer killing effects. So, based on what is currently known, cannabis oil that is most potent in THC content is likely going to be the most potent medicine for curing cancer.
    Raw cannabis in the form of juices and unheated oils are beneficial too and would make a great addition to someone’s treatment, but should not replace cooked cannabis oil, and often require much larger quantities for therapeutic value. Raw or partially cooked oils will contain a wider range of components including cannabinoid acids and terpenes, which are lost when oils are fully cooked, but THC is the most essential cannabinoid for fighting cancer so make sure you decarb your medicine properly to maximise its potency.
    The Rick Simpson method only guarantees partial decarb from the rice cooker stage, and while full decarboxylation can be achieved with the use of a coffee warmer or candle warmer it can take some time to complete this process and other gentle heating devices may not be hot enough. Many of the solvents used have boiling points below the optimum temps for full and rapid decarb. If you do not have a coffee/candle warmer, of even if you do, it is recommended to put your oil in the oven at 110 to 130 degrees Celsius for about an hour. Visible bubbling will cease when the solvent and water, along with volatile terpenes, are boiled off. But you will see very small pin prick explosions on the surface of the oil during decarboxylation. When this has ceased and there is no activity on the surface of the oil at temps of 110c or above, then you know that decarboxylation is complete. While you want to ensure that temperature does exceed 110 degrees Celsius for decarb, it is also advised to stay below 140 as temps above 140 can lead to a loss of THC through vaporisation (157c)or degradation to CBN.
    In an ideal world everyone would have access to both raw and cooked cannabis in a well controlled manner, but in this world where oil making can be expensive and risky it is best to make sure your medicine is as potent as it can be to maximise its potential.
    This info is for anyone unaware of Decarboxylation or confused about how to achieve it.


    • Posted by sidk on March 1, 2015 at 10:12 AM

      I was given a trash bag full of trim (mostly leaf) that I have been experimenting with at making oil (using EverClear as a solvent). I understand the graph. I have been doing 1 oz (28g) batches and am getting varied results, mostly ok (I’m interested in the psychoactive properties).
      However, the point of this post is to raise what I consider to be a conundrum…
      When I bake brownies (using canna oil), typical oven temp/time for a batch might be 350 F for 25 minutes. Extrapolating the graph data for 350 F suggests (to me) that I am cooking all the good stuff (psychoactive) out of the oil. Yet, anyone who has eaten canna infused brownies know that is not the case. So, does that mean that the graph data is bogus in the context of this whole thread??
      Further, does it follow that if the oil is to be used in baked eatables, that it NOT be first decarboxylated?


  7. Posted by Blaz on February 28, 2015 at 2:24 AM

    Mahaffia, I am also wondering that, i have always decarboxylated it in the process of cooking, but i am thinking that it might be better if you put it in the oven at about 110˙C for at least half an hour, and then slowly and safely extract with with a solvent (no danger of overheating) But I am worried that it may effect the quality of the product. Not sure though….


  8. Posted by MattMatt on February 27, 2015 at 4:05 AM

    All cannabinoids start out as cannabinoid acids. So yes, decarbing is necessary to convert THCVA to THCV too. I don’t know the exact temps/times but I would expect full decarboxylation (till activity stops) to mean full decarboxylation of all acids to their neutral counter parts


  9. HI, I’m wondering about decarbing THCV for edibles. Is it necessary for THCV or can you get the full effect of the THCV without decarbing? Also are times & temperatures for THCV decarbing (if needed) the same as THCA?


  10. Posted by mahaffia on February 18, 2015 at 12:54 PM

    What are the pros and cons of decarboxylating the material first, and then extraction with glycerin?


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