Menthol
Also written l-menthol
Quick answer
The cooling compound of peppermint. It feels cold because it opens the same receptor that low temperature does, not because it lowers the temperature of anything.
What it does
Menthol activates TRPM8, the sensory receptor that responds to cold, so a mouth containing menthol reports cold at body temperature. This is the mirror image of how capsaicin produces a sensation of heat, and it is why peppermint reads as cooling in a hot drink. The distinction that matters in cooking is between the mints: peppermint is menthol-led and cools; spearmint, the mint of most savoury cooking from Morocco to South Asia, is dominated by carvone and cools very little. A recipe calling for mint almost always means spearmint, and peppermint in its place gives a toothpaste note that is the menthol doing exactly what it does.
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
- moderate
Menthol is volatile enough to be lost from dried leaf and from long cooking, and oil-soluble enough to carry strongly in chocolate, cream and fat-based sauces, where peppermint’s cooling is at its most pronounced. Because the cooling is a receptor effect rather than a flavour, it does not scale down gracefully: a little peppermint in a savoury dish is noticeable as cold before it is noticeable as mint. For savoury cooking that wants mint’s aroma without the chill, spearmint is the right plant, and dried spearmint — the form used in Levantine, Turkish and Persian cooking — keeps its character better than dried peppermint.
Spices that carry it
Recorded on the compound rather than on each spice, so the two cannot disagree.
- MintPrincipal component
Principal in peppermint and minor in spearmint, whose character is carvone. Which mint is in the jar decides whether menthol is present in any quantity.
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 · Retains Menthol, menthone, volatile oil, yield, moisture
Peppermint left to wilt on the ground before final drying at 30 °C showed only slightly lower essential oil levels than peppermint dried directly at 30 °C, by 7.7 per cent after one day and 1.5 per cent after five, with no change in oil quality. The wilting removed much of the water, reducing the energy needed for the final drying. Oil yield rose from early to full and late bloom, and the compounds that carry the flavour, menthol and menthone, were at their best at full bloom, at 43 to 54 per cent and 12 to 30 per cent of the oil.
Conditions: in air · Final drying at 30 °C · One or five days of wilting on the ground beforehand · Peppermint grown in Norway, three seasons
What this does not show: Read in the abstract only. Peppermint grown for oil in a cool climate; the abstract excludes the 50 and 70 °C treatments from its averages without giving their results.
Measured on the spice
Not to be confused with
Compounds a reader is likely to take for this one, and why they differ.
Carvone
The compound of spearmint. The two mints differ chemically more than they differ in appearance, and the difference is menthol’s cooling.
Camphor
Another cooling-feeling terpenoid, present in rosemary and sage. Camphor’s effect is more medicinal and less clean, and it is not the same receptor story.
Questions this page answers
- why does mint feel cold
- what is menthol
- menthol cooling effect
- peppermint vs spearmint menthol