Eucalyptol: Cooling Camphor Aroma, Facts, CAS Number and Uses

What is eucalyptol?

Eucalyptol is a colourless liquid made of ten carbon atoms, one oxygen atom and a distinctive cage-like structure. Chemists classify it as a monoterpenoid and, more specifically, a cyclic ether: the oxygen forms a bridge across the ring instead of sitting in an alcohol group. Its formula is C10H18O and its molecular weight is 154.25 g/mol, according to PubChem’s eucalyptol record.

Eucalyptol and 1,8-cineole are the same molecule under two names, and you may also see cineol, cajeputol or 1,8-oxido-p-menthane on supplier listings. The name eucalyptol comes from the eucalyptus tree, whose leaf oil is the richest natural source. Unlike limonene or pinene it is not a pure hydrocarbon, and the oxygen is what makes it cooler and cleaner-smelling than the hydrocarbons.

If you are new to the topic, our guide to what terpenes are covers the basics before the detail below.

What does eucalyptol smell like?

Eucalyptol smells fresh, camphor-like and minty-herbal. PubChem records a camphor-like odour and a spicy, cooling taste. Perfumers also describe a clean, slightly woody freshness, and in flavour work the useful words are simply cool, fresh and herbal.

How a eucalyptol-led aroma reads depends on what sits beside it:

• Alone: a sharp, clean, camphor-and-eucalyptus freshness with a faint woody edge.
• With pine and citrus notes: a crisp forest-and-menthol impression, much like a pine needle crushed in the hand.
• With sweet or creamy notes: a cool-mint dessert character, because a little freshness lifts sugar and cream.
• With sage, herbal or skunky notes: a sharp, green, savoury edge that suits strain-style flavours.

Where is eucalyptol found in nature?

Eucalyptol is the major component of eucalyptus leaf oil. Studies of Eucalyptus globulus leaf oil report 1,8-cineole at anywhere from about 17% to 90% of the total depending on the sample, and one detailed analysis in a peer-reviewed paper on eucalyptus essential oil found 63.1% in the oil it tested. That range is a good reminder that natural amounts vary widely with species, region, leaf age and extraction method.

Outside eucalyptus, eucalyptol is reported in rosemary, bay laurel, sage, camphor laurel and a number of other aromatic plants, where it sits beside pinene, camphor and borneol. It is also reported in the aromatic oils of some cannabis varieties, usually in small amounts, which is one reason menthol-and-pine profiles appear in strain-style flavours.

Plant oils are blends. The smell people call “eucalyptus” is the combination of eucalyptol with pinene, limonene and others, so a single-molecule eucalyptol note smells cooler and sharper than the oil it comes from.

What are the key facts about eucalyptol?

The table below puts eucalyptol next to three related molecules so you can compare the numbers. Data comes from PubChem records for each molecule and boiling points are rounded.

A few more figures help with handling. Eucalyptol has a density of about 0.92 g/mL, so it is lighter than water, and PubChem records a melting point of about 1.5 C. Its water solubility is about 3.5 g/L at 21 C, which is higher than most terpenes, and it mixes freely with ethanol, ether and oils. The closed-cup flash point is about 49 C, close to limonene’s, so treat it as a flammable liquid.

How is eucalyptol different from camphor, menthol and borneol?

Eucalyptol belongs to a family of cool, camphor-and-mint smelling monoterpenoids, and the differences between the members are small but audible. Camphor is a ketone, menthol is an alcohol with a saturated ring, and eucalyptol is an ether. Each carries a different functional group on a similar ten-carbon frame, and the group changes how the molecule smells and behaves.

In smell, menthol is sweet, round and peppermint-like, while eucalyptol is sharper, drier and more camphor-like. Camphor is more penetrating and waxy than either. Borneol, which is a close neighbour on the aroma wheel, smells piney and camphor-like with a woody dryness, and our borneol guide covers it in detail.

The naming is a trap. Cineole is a name used for several related molecules, and 1,8-cineole (eucalyptol, CAS 470-82-6) is the common one, while 1,4-cineole is a different molecule. If a supplier lists “cineole”, check the CAS number before you compare.

How is eucalyptol sourced?

Commercial eucalyptol is mostly obtained by fractional distillation of eucalyptus oil, or from other cineole-rich oils such as rosemary and cajuput, then purified to the specification a buyer needs. Because eucalyptus oil is produced at large scale, it is one of the more widely available natural terpenoids.

In flavour and aroma work, eucalyptol reaches a finished profile in one of three ways:

• Isolated or purified: the single molecule, used as a cool, fresh building block.
• Present in a whole plant extract: eucalyptol alongside the other molecules the plant made, as in cannabis-derived terpenes (CDTs).
• Present in a botanical blend: cooling and herbal notes assembled with other botanical-derived terpenes (BDTs) to recreate a target aroma.

A layered blend usually smells more natural, because the molecules that occur together in a plant balance each other. An isolated eucalyptol note is more predictable but can smell clinical on its own, which is why makers use it as an accent rather than a lead.

Which Elite Terpenez profiles have a cool, minty or herbal aroma?

Elite Terpenez does not sell a single-molecule eucalyptol product. Every profile is a blend, and we do not state the contents of any profile, so the table shows each profile’s listed aroma notes only. Profiles with a cool, menthol, mint or sage aroma such as these sit closest to the eucalyptol direction:

For a menthol-and-pine direction with a sage edge, start with ATF, which is sold in three lines so you can compare them. For a sweeter, creamier cool mint, look at Kush Mintz DNA. For a clean mint with no skunk, look at Spearmint Supreme or Mojito. Mint profiles are not eucalyptol, but they sit in the same cool, herbal family on the aroma wheel. To browse more, see the Diamond Line, Natural Terpenes and Premium Line collections, or the full Flavour Catalogue.

For cannabinoid content of any profile other than the Diamond Line, contact us and we will confirm before you order. Diamond Line terpenes contain no THC or other cannabinoids. Cannabis flower is a controlled drug in the UK and Elite Terpenez does not sell cannabis.

What does eucalyptol pair with?

Cool, camphor-like notes work as an accent, and many popular flavours are a fresh, minty lift over something sweet, piney or earthy. Use these pairings as a guide when you plan a blend or choose between profiles:

These are separate profiles from the Elite range, each with its own listed notes. They show the direction of the pairing and say nothing about what any bottle contains. For the pine side of the aroma wheel, our pinene guide covers the resinous partner that often sits beside eucalyptol in plant oils, and our humulene guide covers the dry, woody base layer.

How do makers use eucalyptol for flavour and aroma?

Makers use cool, camphor-and-mint notes to add freshness and lift to a recipe. They are popular where a sweet, creamy or fruity flavour needs a clean edge, and in strain-style recipes where a sharp, herbal top note is part of the target. They also work well with citrus and pine.

A few practical points:

• Use it as an accent: a little cooling note goes a long way, and too much turns harsh and sharp in a way that reads as a menthol rub rather than a flavour.
• Build, do not stack: pair cool notes with sweet or fruity ones to avoid a flat, single-note result.
• Test small: run a small batch, wait a day, and re-smell it before scaling.
• Expect it to fade first: eucalyptol is more volatile than the sesquiterpenes, so a cooling top note can fade before the base does.

What are the starting cuts and handling rules?

Terpene profiles are concentrated and must never be used undiluted. Elite Terpenez’s starting cuts are 6% for vape cartridges, 4% for concentrates, 2% for tinctures, 1% for edibles, 0.5% for beverages and 3% for topicals. Use the terpene mixing calculator to turn a percentage into a weight, and always test a small batch first.

Eucalyptol has a notable hazard profile. PubChem’s classification lists it as a flammable liquid and vapour and, in most notifications, as a skin sensitiser that may cause an allergic skin reaction. Wear gloves and eye protection, keep every bottle away from children, pets, heat and flames, and work in a ventilated space. For general workplace guidance, see the HSE’s COSHH basics. Products are for adults (18+) only. This guide is about flavour and aroma, and it is not medical advice.

Storage

Store terpene bottles tightly closed in a cool, dark place; refrigerated is ideal. Light, warmth and air speed up oxidation, so a half-empty bottle left open will lose its freshness faster than a full, closed one. Decant what you need and reseal promptly.

If a cool, minty profile starts to smell dull, flat or sharp rather than fresh, it has probably aged. It is better to test a fresh bottle than to adjust your recipe to compensate. Label the date you opened each bottle so you can track how long it has been in use.

Sizes and bulk

Profiles come in 2 ml, 5 ml and 10 ml bottles. For larger runs, ask about bulk on the wholesale and bulk page. Free UK delivery on orders over £80.

Frequently asked questions

Ready to build a cool, fresh flavour? Browse the Diamond, Natural Terpenes and Premium ranges, order samples in 2 ml bottles, or contact us for bulk quantities and to confirm anything about a profile before you order.