More herbies are trying their hand at home distillation, now that small distillation units are becoming more widely available. Water-based plant extracts, called hydrosols, can be used creatively in cosmetics and cooking. (Lemon verbena hydrosol can be added to sorbet, for instance.) Intensely fragrant and flavorful, herbal waters seem to concentrate a plant’s best properties.
Yet many of the herbs’ most potent health benefits appear to be left behind, according to recent research conducted in Spain. Using chromatography and mass spectrometry, the Spanish researchers found the plant waste left after lavandin (Lavandula ×intermedia) distillation contained high amounts of flavonoids, compounds believed to help prevent cancer and other diseases. Distillation separates molecules based on their volatility or boiling points, so only the volatile compounds are distilled into hydrosols or essential oils, leaving the non-volatile compounds behind in the plant waste.
So while distillation is the best way to obtain waters and oils with aromatic properties, it might not be best for obtaining healthful antioxidants.
For more information, see Journal of Agricultural and Food Chemisty 55:8436-8443.
Cindy Jones, Ph.D., is owner of SageScript Institute (