Vape pens, portable vapes, desktop vaporizers, enails, and dabbing; vaping can take many forms and not every vaporizer and type of vaporization is created equally. What is clear is that vaping has had a seismic impact on the cannabis market, and with new products coming out every year, there is something for everyone.
Vaporization vs. Combustion
There is a hot debate around what technically is vaporization and what is combustion. While water vaporizes at 100°C/212°F, everything has a different vaporization point, including all the different cannabinoids and terpenes in cannabis.
Most of the common terpenes in cannabis have a vaporization point between 155°C/311°F and 213°C/415°F. Most of the major cannabinoids have a vaporization point somewhere between 157°C/315°F and 220°C/428°F, but some, like the acidic cannabinoids THCa and CBDa begin to vaporize at lower temperatures, decarboxylating into THC and CBD with heat. In a 2006 study, Arno Hazekamp and his team of researchers observed that using the highest temperature setting on a Volcano vaporizer caused the “maximum delivery of THC,” as 33% of the THCa was converted to THC.
While those are the vaporization points, the point of combustion, where something burns, is a little different, but also depends on the substance being burned. For organic matter, like dried cannabis or books, Fahrenheit 451 is generally viewed as the temperature where combustion begins, but signs of combustion may happen sooner, like charring in areas more prone to burning (the leaf tips of cannabis versus the stems). The goal of effective and efficient vaporization is to access as many cannabinoids and terpenes as possible without causing combustion. By avoiding combustion, it is possible to avoid many of the carcinogens produced by smoking or charring food (yes, even the char in your barbeque has some carcinogens in it), which makes vaping much healthier than smoking.
So in short, a vaporizer should be creating vapor (in the case of cannabis, a diffuse fog of cannabinoids, terpenes, flavonoids, and other molecules), but not smoke, which requires combustion from excessive heat.
High vs. Low Temp Dabbing
Most resources online say that the temperature range for a “low temperature dab” is between 400 and 500°F, which as we just learned, is potentially not vaporization depending on how close to 500°F it is. According to Leafly, dabbing temperatures range between 204°C/400°F and potentially over 316°C/600°F for “hot dabs.” A 2017 study looking at dabbing temperatures found that above 403°C/757°F, various toxicants could be formed including benzene and methacrolein, with the greatest amount being produced above 526°C/978°F.
So clearly, most dabbing is not technically a form of vaporization, as the temperature is too high and some combustion will occur, and possibly the formation of toxic by-products if the heat is not controlled. If an e-nail is used to keep temperatures well below 450°F then it would be true vaporization, rather than a combination of vaporization and combustion.
Conduction – Direct Heat
Conduction is the most basic type of heating, caused by direct transfer of heat. For example, heating a pot on your stove uses conductive heat from either the gas or electric burner to warm the pot. When it comes to cannabis, when the fire from a lighter is applied to a bowl of flower, the flower is ignited by direct conductive heat. Similarly, the nail in dabbing is heated by conduction either from a blowtorch or electric power supply.
Conduction-based vaporizers are known for being able to produce much bigger, thicker clouds of vapor, but runs the risk of burning the cannabis flower or concentrate, and that partial combustion results in a worse flavor. Even worse, a poorly designed conduction vaporizer can actually fully combust plant matter inside, causing a fire inside the vaporizer (which this author has observed in multiple conduction-based vaporizers). All vape pens use conductive heating, where a heating element is inside a cartridge filled with cannabis oil, and low quality devices will smolder the oil closest to the heat source, leading to partial-combustion rather than true vaporization of the oil.
Convection – Indirect Heat
While conduction was direct heat, like from a stovetop, convection is indirect heating, through air or the movement of another fluid, such as in a convection oven where the air is heated and that heated air cooks the food inside. The main benefit of convection is there is a much lower risk of combustion using an indirect heat source, as evidenced by convection ovens reaching temperatures over the point of combustion, but not burning the food inside.
For cannabis vaporizers, convection means tastier vaping, as less of your terpenes are burnt off by harsh conductive heating. So while you may not be blowing massive clouds of, what could be smoke, you will be enjoying all the terpenes and natural flavors of the cannabis in your vape, with greater health benefits as there will be a lower chance of partial-combustion taking place. For these reasons, many vapers prefer the benefits of convective heating over conduction, as convection generally is truly vaporizing the product, but with conduction it really depends on the quality of the device being used.
Induction – Electromagnetic Heat
Whereas convection and conduction both are forms of heating that differ when it comes to physical contact (how close the heat source is to the fuel/cannabis), induction is a radically different form of heating that has recently begun to see use in the cannabis vaporizer market.
Induction is a form of heating that uses electromagnetic energy to pass heat through an inductor, causing something to heat up internally, rather than transferring heat to it through direct or indirect contact. As the heat is generated internally, this generally results in much faster heating. Faraday’s Law, the same principle that is behind the magic of a Faraday cage (where someone can be “electrocuted” but the suit absorbs it), is also what powers inductive heating in vaporizers and on induction stovetops. Like convection vaporizers, induction vaporizers produce a better tasting vapor and a smaller cloud than conduction.
A Quick Hit
So in the end, what type of vaporization is best? It depends on what matters to you the most. If you want the biggest, thickest clouds you can blow, then you are looking for a conduction vape. If you want a better flavor and don’t care about blowing huge clouds (that may actually be smoke, rather than vapor), then go for a convection or an induction vaporizer.