If it disappears, it is an essential oil. Essential oils are a diverse mixtures of molecules. The kind and concentration of molecules in the oil determines its odor. The molecules typically have 20 carbon atoms or fewer and are hydrocarbons, terpenes, alcohols, phenols, esters, aldehydes and ketones. Plants and essential oils A .
Essential oils occur in numerous different plants, but especially tropical and subtropical species.
They occur in more than 60 families and are especially common in the Mint, Citrus, Laurel, Myrtle, Geranium and Carrot families. Most of our commercially-important essence producing plants come from Asia, Africa and tropical America. Essential oils are found in all parts of the plant, including flowers, roots and leaves. Different organs usually yield different oils. The actual oil that is produced is dependent on plant age, maturity and climate.