Plate II
Uap
Cinnamomum burmanni
Field notes on distillation: why one plant yields different materials depending on the part and the method.
Steam separates, it does not extract everything
In steam distillation, steam passes through plant material and carries the volatile compounds with it. The mixture is cooled, then oil and water separate because their densities differ. What stays in the plant stays in the plant.
So a distillate is not “the whole plant in a bottle”. It is the small fraction light enough to travel with steam.
Time and pressure change the result
A distillation stopped early smells different from one carried on for hours. With ylang-ylang the difference is used deliberately: the early and late fractions are sold separately.
Sandalwood and vetiver take the longest, sometimes more than a day, because their compounds are heavy and slow to travel.
Cold expression
Citrus peel is not distilled. The oil sits in glands just under the surface of the rind, and pressure alone releases it. No heat is involved.
Precisely because there is no heat, heavier compounds come along — including the ones that make skin sensitive to sunlight.