Estragole
Also written methyl chavicol, p-allylanisole
Quick answer
Anethole’s isomer: the same formula rearranged, smelling greener and more herbal, and — unlike anethole — the subject of a regulatory assessment that is routinely misreported as a warning about eating fennel.
What it does
Estragole smells of anise pushed towards green herb — it is the dominant aromatic of tarragon and a large part of what distinguishes one basil cultivar from another. Where it appears alongside anethole in fennel and aniseed it lifts the sweetness towards something fresher and less confectionery. The proportion varies substantially with cultivar and with the part of the plant used, so two fennel seeds from different origins can read quite differently on this axis.
How it behaves when cooked
Four properties of the molecule, and what they mean at the stove.
- Volatility
- high
- Fat solubility
- high
- Water solubility
- low
- Heat stability
- moderate
Estragole behaves in the pan much as anethole does — fat-soluble, water-shy, volatile — with one difference that matters to anyone cooking with tarragon or Asian basil: it is the first thing lost when those leaves meet sustained heat, which is why both are added at the end and why dried tarragon is such a poor stand-in for fresh. In seed spices it travels with the anethole and needs no separate handling.
Spices that carry it
Recorded on the compound rather than on each spice, so the two cannot disagree.
- Avocado leafPrincipal component
The compound that makes the Mexican race of avocado the culinary one: its leaves smell strongly of anise and the Guatemalan and West Indian races grown for commercial fruit carry little of it. A Oaxacan bean pot and a French tarragon turn out to share a molecule.
- TarragonPrincipal component
The dominant compound in French tarragon and the source of its anise character. Its concentration is also what separates the French cultivar from the near-flavourless Russian one, so this single compound accounts for the whole of the distinction a cook cares about.
- BasilMajor component
A principal aromatic in several cultivars and a minor one in others. Cultivar differences in basil are largely differences in the balance of estragole, linalool and eugenol.
- ChervilMajor component
The same compound as in tarragon at much lower concentration, which is precisely why chervil is delicate where tarragon is assertive rather than being a different kind of anise.
- Hoja santaMajor component
One of the two anise-type compounds that give the leaf its distinctive character, alongside anethole.
- AniseedContributing component
- Fennel seedContributing component
Not to be confused with
Compounds a reader is likely to take for this one, and why they differ.
Anethole
Identical molecular formula, different arrangement, different smell and entirely different regulatory status. Reports that conflate them produce the widely circulated and incorrect claim that fennel seed is restricted.
Regulatory position
Held on the compound, because the restriction is a fact about the molecule rather than about any one spice.
European Union
restricted in some foodsEMA/HMPC public statement on herbal medicinal products containing estragole
The European regulator assessed estragole exposure from herbal medicinal preparations and advised limiting sustained exposure from concentrated products. The assessment concerns medicinal preparations and prolonged use; it does not establish a hazard from culinary quantities of fennel seed, tarragon or basil, and citing it as though it did is the commonest misuse of this document.
Safety
What the concern is. The dose, the population and the evidence level live on the spice profiles, which is where a reader with that question actually arrives.
The concern attaches to concentrated preparations and sustained medicinal exposure, not to seasoning food. SpiceHQ states the regulatory position and declines to convert it into a caution about cooking, because the source explicitly does not support one. The fennel and aniseed profiles record the same boundary.
Questions this page answers
- what is estragole
- what does estragole do
- which spices contain estragole
- what is methyl chavicol
- what is p-allylanisole