What Is the Essence of a Plant?

People speak of ‘essential oils’ and almost always mean a single liquid in a single bottle. What is actually distilled from a lavender field, though, is a mixture of often more than a hundred different volatile molecules — linalool and linalyl acetate make up the lion’s share, but only their interplay with dozens of minor components, in shifting proportions, produces the scent instantly recognized as ‘lavender’. There is no single substance called lavender. There is an orchestra.

This composition, moreover, is anything but constant. Soil, altitude, the weather in the year of harvest, the timing of the harvest, even the hour of the day it is cut all shift the ratios between the molecules — two harvests from the same field can differ noticeably, and the very same species smells different at altitude in Provence than it does in the lowlands. What gets distilled, then, is not ‘the’ essence of the plant, but a snapshot: the chemical answer this particular plant gave to this particular year, this particular soil.

On top of this, different extraction methods applied to the very same plant produce genuinely different ‘essences’. Steam distillation yields the classic essential oil, but heat-sensitive flowers such as jasmine or tuberose barely survive this process intact and are instead processed through enfleurage — the slow embedding of fresh blossoms in odorless fat — or through solvent extraction into what is called an absolute, which differs noticeably in composition and scent from a distilled oil of the same plant. Modern CO2 extraction adds a third, again different variant. There is thus not even a single possible ‘essence’ per plant, but several, depending on which method one meets it with.

The word ‘essence’ comes from an older, Aristotelian idea that every thing carries an unchanging, essential core that makes it what it is — a notion that has stubbornly survived into modern perfumery language, even though chemistry has long since drawn a different picture: not a core but a process; not a substance but a relationship between hundreds of molecules and their own unrepeatable surroundings.

Perhaps that is the real reason scent is so hard to put into words. Whoever smells ‘lavender’ is not smelling one thing, but a small entire story — cut from a particular slope, in a particular summer, at a particular hour. The idea of a single ‘essence’ is convenient, but it conceals what is actually happening: every plant renegotiates with its environment anew, every year, and the scent is the record of that negotiation.