Distillation

Distillation collects material by turning it into vapor and cooling that vapor back into liquid. In botanical distillation, water and steam carry aromatic constituents from plant material into a collected distillate.[1,2]

From plant to vapor

In water distillation, the plant material is heated in water. In steam distillation, steam passes through it. Some arrangements combine these approaches.

The vapor travels into a condenser, where cooling turns it back into liquid. Aromatic water, called a hydrosol, is collected, and a separate essential oil may also form.

Constituents able to enter the vapor under these conditions are described as volatile. This property helps determine which portion of the plant’s chemistry distillation gathers.

What travels through the still?

Botanical distillates commonly contain terpenes and terpenoids, a large group of plant compounds that includes many familiar aromatic substances.

Some are hydrocarbons, such as pinene and limonene. Others contain oxygen-bearing groups and are described as alcohols, esters, aldehydes, ketones or oxides. These names identify chemical features that influence properties such as aroma and water solubility.

The essential oil and hydrosol gather different mixtures of these constituents. Large polysaccharides, tannins and most fatty materials largely remain in the still.[3,2]

Distilling at Deschampsia

We distill our hydrosols and many of our essential oils ourselves, in house, using a copper alembic still. Our process combines hands-on work with precise measurements and standards for the botanical materials we use. Preparing the plant material, managing the distillation and collecting the hydrosol and essential oil are all part of that work.[4,5]

Related entries: Hydrosols; Essential oils; Extraction & solubility.