Terpene Boiling Points: Why Most Charts Are Misleading

Last updated on August 5, 2026 · Originally published February 13, 2023

If you have looked up terpene boiling points, you have probably seen the chart. Pinene at 311°F, myrcene at 332, limonene at 348. Humulene, oddly, at 222.

That last number is wrong as presented, and following it turns out to be a useful exercise. The same figures appear on a Cornell University hemp extension page that credits a Leafly consumer infographic as its source, and are reproduced verbatim inside a granted US patent — number 10,596,486, where they appear as “temperatures of vaporization.”

What the humulene figure actually says

Look up humulene in the NIST Chemistry WebBook and you find a boiling-point measurement of 396.2 K at 0.013 bar — roughly 123°C at 10 mmHg. That is a strong vacuum, the kind used to move a compound without prolonged heating, not atmospheric pressure.

Atmospheric pressure is around 760 mmHg. Under vacuum a heavy compound boils far below where it would in open air, which is the entire reason vacuum distillation exists.

The chart in circulation gives a different figure, 106°C, with no pressure condition attached at all. We have not been able to establish where that exact number originated. What is clear is that it cannot responsibly be presented as humulene’s ordinary atmospheric boiling point.

Nerolidol shows the same pattern. NIST reports mixed nerolidol isomers boiling at approximately 112 to 114°C at 0.001 bar, around 0.75 mmHg. Again, this is a vacuum measurement for a relatively heavy compound, presented in cannabis charts as though it were an ordinary boiling point.

Why a missing pressure condition matters more than a typo

The pressure error is not random. It affects the heavier compounds most dramatically, and can invert the thing the chart is supposed to tell you.

Many of the lighter figures in these tables are broadly right and correspond to normal boiling points: alpha-pinene around 156°C, myrcene 167°C, limonene 176°C, linalool 199°C.

So the chart shows the heavier compounds with lower numbers than the lighter ones, which reads as the heavy ones are more volatile. The truth is the reverse. Sesquiterpenes contain half again as many carbons and are generally considerably less volatile, so they often persist after much of the lighter fraction has been lost.

Anyone setting a vaporizer temperature from that chart is working from an upside-down map.

Not every questionable entry is a heavy compound, either. Ocimene appears in the copied chart at 50°C — a figure that cannot be an atmospheric boiling point. We have not been able to establish where that number originated. What can be established is where it travelled: Cornell’s page and the patent both carry it, unchanged.

Boiling point is not an evaporation threshold

Even with every figure corrected, a boiling-point table answers a question nobody is really asking.

A boiling point is the temperature at which a liquid’s vapour pressure equals the surrounding pressure, allowing vapour bubbles to form throughout the liquid. It is not a line below which nothing escapes. Volatile compounds can evaporate steadily at temperatures well below their boiling points — that is why an open jar of flower loses its smell at room temperature, and why you can smell anything at all.

Nor is a boiling point a decomposition temperature. Thermal degradation is a separate process with its own chemistry, and it does not switch on when boiling begins. Charts that describe these figures as “the temperature at which a terpene starts to break down” are describing something that does not happen.

The central physical property behind that tendency is vapour pressure — the pressure produced by a compound’s vapour at a given temperature. How fast it is actually lost also depends on time, airflow, surface area and what surrounds it. A 2023 review in Cannabis and Cannabinoid Research worked through cannabis terpene loss on exactly this basis, and its authors were blunt about the state of the field: product labelling in this area contains substantial errors regarding boiling points and vaporization temperatures. They found composition shifting during drying and curing, before any deliberate heat, with the lighter compounds leaving preferentially because their vapour pressure is higher.

A more honest table

Here is the comparison in a form that at least does not mislead. Every figure is an atmospheric boiling point unless a pressure is stated, and the two groups are separated because the difference between them is the whole point.

C10 compounds — monoterpenes and monoterpenoids, generally more volatile

Normal boiling points, meaning at one atmosphere.

Values from the NIST Chemistry WebBook, which is searchable by compound name. Where NIST reports a range of measurements, the figure above is representative; terpinolene is given as a range because its reported values span more than a degree.

C15 compounds — sesquiterpenes and sesquiterpenoids, generally less volatile

Here the picture is different, and more revealing. These compounds are commonly characterised under reduced pressure, so many of the readily traceable measurements come with a vacuum attached — while the figures in circulation often come with nothing attached at all. The measurements below are not necessarily the sources of the copied figures. They show why a temperature without its pressure condition is incomplete and potentially misleading.

Humulene and nerolidol figures from the NIST Chemistry WebBook; the β-caryophyllene measurement from Tokyo Chemical Industry product data. Fahrenheit values throughout were converted from the cited Celsius figures and rounded.

The last column is the point. Those figures circulate without conditions, and where measurement conditions are known for the same compounds, they were taken under strong vacuum. Set beside the C10 values, they make the heaviest compounds in cannabis look like the most fragile.

Three qualifications matter. Normal boiling points for the heavier compounds are less consistently reported, in part because they are commonly characterised under reduced pressure to limit prolonged heating and thermal degradation.

None of these figures are decomposition temperatures. Every compound here has a measurable vapour pressure below its boiling point and can therefore be lost without ever reaching the listed temperature.

There is a further complication: suppliers commonly list β-caryophyllene at 262–264°C without stating a pressure. That conventionally indicates a normal boiling point, but conventionally indicating is not the same as explicitly stating — which is rather the theme here.

Ocimene is absent from these tables deliberately. “Ocimene” can refer to different geometric isomers or to a commercial mixture, and we could not find a pressure-explicit atmospheric measurement specific enough to publish.

Why terpenes disappear during processing

This is where the numbers become genuinely misleading, because a compound does not need to reach its boiling point to leave.

Rick Simpson Oil makes the problem easy to see. A typical ethanol extraction need never approach the listed boiling point of any terpene in it, yet the finished oil smells little like the plant it came from.

Evaporation does not wait for boiling. A puddle dries without reaching 100°C, and terpenes escape by the same basic process. Heat accelerates the loss, but time, surface area and airflow matter too.

Solvent removal adds a second route. As ethanol evaporates, volatile compounds can enter the outgoing vapour with it — they do not sit untouched simply because their own boiling points are higher. This can be a major source of loss during ethanol removal. Steam distillation demonstrates the broader principle: plant material and water are boiled at around 100°C, and aroma compounds boiling at 150 to 260°C are collected from the vapour. The mechanisms are not identical — water and essential oils are largely immiscible where ethanol and terpenes are not — but the lesson carries. A high-boiling compound can enter the vapour phase at a bulk temperature far below its own boiling point.

Then there is duration. An extraction may spend hours warm, stirred and exposed across a large surface, followed by decarboxylation. The cumulative loss matters more than whether the material ever crossed a number printed on a chart.

What survives processing, and what decides it

The useful version of all this is comparative rather than absolute.

As a broad rule, C10 compounds such as myrcene, limonene, ocimene and pinene tend to be lost sooner. C15 compounds such as beta-caryophyllene, humulene and nerolidol are generally less volatile and often more persistent. This helps explain why heavily processed material can lose bright citrus and pine notes while retaining a larger proportion of woody and peppery compounds.

Beyond that, how much survives depends on things no chart can capture: how long the material was held at temperature, whether air was moving over it, whether oxygen was present, what the material was mixed with, and whether the process ran open or closed. Two producers using the same nominal temperature can end up with very different profiles.

Oxidation is a separate route out. Terpenes do not only evaporate; they react. Beta-caryophyllene converts to caryophyllene oxide on exposure to air, and linalool oxidises into compounds with quite different properties. A compound can be lost without ever reaching a temperature that would boil it.

If you are setting a vaporizer temperature

No published number will tell you exactly what you are preserving, and it is worth being clear about that up front.

Lower settings tend to emphasise the lighter aromatic compounds and produce a gentler flavour. Higher settings extract cannabinoids more completely but also accelerate terpene loss and thermal transformation. The result is a trade-off, not a precise sequence of compounds unlocked at particular temperatures.

What you can rely on is the ordering. As a general rule, the bright top notes disappear sooner than the heavier base notes, and no setting recovers what has already gone. That is worth more than a table of numbers, particularly when some of those numbers were measured in a vacuum.

For the wider context, see our guide to cannabis terpenes.

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Updated August 5, 2026. This article previously presented a table of terpene “burning points,” describing them as temperatures at which terpenes begin to break down. That framing was incorrect, and several of the values reproduced were vacuum-distillation figures published without their pressure conditions. The article has been rewritten to explain the error, its origin, and what actually governs terpene loss during processing.

Research for this article was compiled using DeepWeed, T&T’s cannabis research database — explore the underlying studies there.

Sources

1. Eyal AM, et al. Vapor pressure, vaping, and corrections to misconceptions related to medical cannabis’ active pharmaceutical ingredients’ physical properties and compositions. Cannabis Cannabinoid Res. 2023. doi:10.1089/can.2021.0173
2. NIST Chemistry WebBook — α-Humulene, CAS 6753-98-6. Supports the 0.013 bar measurement.
3. NIST Chemistry WebBook — α-Pinene, CAS 80-56-8, boiling point data
4. NIST Chemistry WebBook, searchable by compound name. Source for the remaining C10 normal boiling points and the nerolidol mixed-isomer measurement.
5. Tokyo Chemical Industry. β-Caryophyllene, product C0796. Reference properties: boiling point 116 °C at 10 mmHg.
6. Cornell University hemp extension, Characterizing terpenes and other natural products in CBD hemp. Carries the chart and credits a Leafly infographic as its source.
7. US Patent 10,596,486. Reproduces the same figures as “temperatures of vaporization,” including humulene at 106 °C and ocimene at 50 °C.