Carvacrol
Also written carvacrol (phenol)
Quick answer
Thymol’s isomer, and the compound that makes oregano taste of oregano — the two are the same atoms differently arranged, and the ratio between them is what separates two herbs that grow side by side.
What it does
Carvacrol is warm, peppery and pungent where thymol is sharp and medicinal — rounder, more herbaceous, with a distinct heat at the back. It is what a reader means by "oregano", and its dominance is why oregano stands up to tomato, lamb and charcoal in a way thyme does not. Because the thymol-to-carvacrol ratio varies with cultivar, climate and harvest, oregano from different origins genuinely tastes different rather than merely differing in strength: Greek oregano is typically carvacrol-forward and assertive, and much of what is sold as oregano elsewhere is milder because the balance sits differently.
How it behaves when cooked
Four properties of the molecule, and what they mean at the stove.
- Volatility
- moderate
- Fat solubility
- high
- Water solubility
- low
- Heat stability
- high
Like thymol, carvacrol is stable and fat-soluble, and oregano is consequently one of the very few herbs that is arguably better dried than fresh — drying concentrates the phenols while the fragile green aromatics that contribute little are lost anyway. That single fact explains why dried oregano is a respectable ingredient in traditions that would never use dried basil, why it is added early to a sauce rather than at the end, and why rubbing it between the palms before adding it is worth doing: the friction warms and fractures the leaf and releases the phenols that are otherwise locked in the dried tissue.
Spices that carry it
Recorded on the compound rather than on each spice, so the two cannot disagree.
- Mexican oreganoPrincipal component
Carries the phenols alongside a citrus-and-anise fraction absent from Mediterranean oregano, which is why the substitution works in a Mexican dish and produces something noticeably wrong in a Greek one.
- OreganoPrincipal component
- SavoryPrincipal component
- TosignPrincipal component
Almost half, 49.90 per cent, of the oil distilled from fresh leaves of Thymus schimperi gathered near Goba in Ethiopia in 2019. One sample; another group reports an Ethiopian thyme oil led by thymol instead.
- Za'atar herbMajor component
- MarjoramContributing component
Present in the same genus as oregano and at far lower levels: 0.1 per cent or less in the two marjoram oils read, both led by terpinen-4-ol. That proportion is why marjoram is sweet where oregano is pungent.
- NigellaContributing component
- ThymeContributing component
What cooking and processing were measured to do to it
Findings from studies in which this compound was followed through heat, fat, water, drying or storage. Each belongs to its study and its conditions.
Drying · Decreases Carvacrol, Thymol, γ-Terpinene, volatile oil
Fresh Polish oregano held 33.0 g of volatiles per kilogram, with carvacrol, thymol and γ-terpinene the main components. Drying lowered the total whatever the method, but by very different amounts: to 10.2 g/kg after convective drying at 60 °C, 13.1 g/kg after convective pre-drying with a vacuum-microwave finish, and 27.9 g/kg after vacuum-microwave drying alone.
Conditions: Convective drying at 60 °C · Compared with vacuum-microwave drying and with convective pre-drying followed by a vacuum-microwave finish
What this does not show: Read in the abstract only, which does not state the basis (fresh or dry weight) of the figures or the fate of the individual compounds. One lot of oregano.
Measured on the spice
Decontamination · Depends on conditions Carvacrol, Thymol, microbial load, water activity, colour, volatile oil
Infrared heating of moistened oregano reduced inoculated Bacillus cereus spores by 5.6 log units after 10 min at 90 °C; at 100 °C for the same time the reduction was lower, 4.7 log units, which the authors link to the water activity having fallen to 0.76 during treatment. The green colour was only slightly affected. The composition of the headspace volatiles was clearly altered, but carvacrol and thymol, two of the key aroma compounds, were only slightly affected compared with the other compounds studied.
Conditions: 90 and 100 °C · Holding times of 2 and 10 min · Oregano conditioned to water activity 0.88, in a closed infrared heating unit
What this does not show: Read in the abstract only. The oregano was moistened before treatment and would have to be dried again. Which volatiles were lost is not stated in the abstract.
Measured on the spice
Decontamination · Depends on conditions Thymol, γ-Terpinene, p-Cymene, Carvacrol, monoterpene hydrocarbons, oxygenated monoterpenes, microbial load, volatile oil
Sicilian oregano, whose oil consisted mainly of thymol and γ-terpinene with p-cymene, α-terpinene and carvacrol, showed a changed oil profile after gamma irradiation: fewer monoterpene hydrocarbons and more oxygenated monoterpenes. Total bacterial and fungal counts fell below 10 cfu/g at the lower dose, 5 kGy. A sensory panel found significant differences between irradiated and untreated oregano for every descriptor except bitter, pungent, astringent and hay.
Conditions: Gamma irradiation at 5 and 10 kGy on three cultivated Sicilian oregano samples
What this does not show: Read in the abstract only, which gives no percentages and does not say in which direction the sensory descriptors moved.
Measured on the spice
Not to be confused with
Compounds a reader is likely to take for this one, and why they differ.
Thymol
The same molecular formula. Between them they account for most of what distinguishes thyme, oregano, savory, za’atar and ajwain from one another, and for why those five substitute for one another with mixed success.
Questions this page answers
- what is carvacrol
- what does carvacrol do
- which spices contain carvacrol