What Is The Real Boiling Point of THC?

Wikipedia can be a great source of information, but don’t always trust it. When it comes to numerical values, like the boiling point of a compound, normally Wikipedia gets close enough because something so simple is easy to agree on, and all the primary sources will provide roughly the same value. But what if we’re dealing with a chemical that has been illegal under federal law since 1937?

“I have seen conflicting reports about the vaporization point of THC,” says Dale Gieringer, PhD. Specifically, the Wikipedia page for THC says the boiling point for THC is 315 °F, and cites this article called Cannabis and Cannabis Extracts: Greater than the Sum of Their Parts? by John M. McPartland and Ethan B. Russo as a source for that number. That article includes a table with the boiling points of seven cannabinoids and cites three different primary sources for those values.

On the one hand you might think the boiling point of THC is 315 °F, but other sources list a different value. Pubchem, an online database of chemical compounds lists the boiling point of THC as 392 °F at 0.02 mm of Hg (a low pressure). Pubchem cites the National Toxicology Program (NTP) as their source. Looking deeper, we see on page 13 of the NTP’s report on THC lists the boiling point as 200 °C, or 392 °F. There’s one catch to this number though, it’s listed as the boiling point of THC at 0.02 mm Hg, meaning 392 °F is the boiling point of THC under a pressure that’s almost a vacuum.

Here’s a quick reminder from high school chemistry class: boiling points are always lower at lower pressures. According to an article by Dale Gieringer called Marijuana Water Pipe and Vaporizer Study, “the vaporization point at normal atmospheric pressure appears to be unknown, but is thought to be in the range 250-400º.”

So where lies the final verdict on the boiling point (a.k.a. vaporization point) of THC? We don’t know, but it’s definitely higher than 315 °F, and probably ever higher than 392 °F. This isn’t to say that cannabinoids won’t start to vaporize at temperatures as low as 300 °F, but other factors are at play in this scenario. Some people may prefer the taste and milder experience of low-temp vaporizing and low-temp dabbing, but those who want a higher yield on their product should definitely aim for a higher temperature.

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  1. Well, I vape weed at 356 Fahrenheit (180 celcius) and always get high as a kite. So no need to go all the way to 392.

    1. Same here bud; 356F and 365f seem to be the magic vape numbers. Did 350F and was alright but 356F seems perfect. I did try 365F and able to cook the herb faster but sadly burn through a bowl faster than 356F. So I feel 356F gives you good terps and THC lasting slightly longer while 365F

      1. I start at 365F and do a sesh that way until I am as high as I want to be. Then I use that same bowl and vape it at 381F. I get two really nice sessions out of one bowl doing it this way. I use a Crafty+ vaporizer with a dosing capsule, FYI.

  2. You are all familiar with humidity, right? Boiling point the temperature where the liquid vapor will occupy 100% of the gases at the pressure above the liquid. Water boils at atmospheric pressure at 212 F, so at 212 F the water vapor at the surface of the boiling water is 100% — there is no air at the boiling water surface, only 100% water vapor. That’s why a boiling kettle whistles — it has chased out all the air in the kettle and the continued boiling of the water is releasing 100% steam at a slight pressure.

    But at 120 F, a hot shower or bath temperature, there is still evaporation of water. At the surface of a hot bathtub, about 1/8th or 12% of the “air” is water vapor and the rest is the air gases (nitrogen, oxygen, etc.). As the temperature rises to 175F, almost half of the gas at the water surface is water vapor, which is crowding out the air gases.

    So now back to vaping. If you vape at 356 Fahrenheit (180 celcius) AT ATMOSPHERIC PRESSURE (at which you are living, right), the THC is not “boiling”, but it is being released at some rate well above room temperature of 72F. Vaping at 392 at ATMOSPHERIC PRESSURE probably is releasing the cannabinoid at well less than 5% of “boiling”.

  3. My poor man’s substitution for the e-nail is to put cold concentrates in a quartz double banger, heat briefly to boil off the water in all dispensary hash, then heat a set number of seconds with a torch. With practice, the execution has become nearly flawless, and i have learned a good deal about what is vaping off when by starting as low as possible to get vapor, 8 sec with a Scorch torch, inhaling that, then waiting 15 minutes. The charts confirm my experience, that the THC goes first. Through trial and error i found that the higher temperatures eventually taste more like crayons, but also have all the indica effects, so settled on 16 sec as the best balance of meds vs burnt wax flavor. While i do not know the actual temps, my timing in consistent for my own 8 and 16 count. Reclaim has much less THC but a greater concentration of those lipids that also contain the most expectorant, hence the cough. Dewaxed shatter has an awesomely low cough effect, but no one sells it commercially yet. Propane shatters have a higher final vape point than butane shatters. Shining a black light into the double banger will reveal if there is still medicine available to heat and inhale.

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