Techniques for the extraction of active components from natural substrates have evolved significantly from early days.
The earliest extraction process was the digestion of flowers or spices in oil. This was followed by the extraction technique called enfleurage, the cold absorption of volatiles on fats. Essential oils were obtained by cold expression, and later, also by distillation. In later years, the process of extracting raw materials by various solvents, such as hexane, benzene, alcohol, etc. became widely used. After extraction, the solvent is removed by distillation, leaving a resinoid or concrete. Alcoholic extraction of the concrete produces an absolute, which is the typical commercial form.
Each of these processes can produce very high quality fragrance and flavor ingredients. However, elevated temperature (from distillation) and solvent usage can detract from total quality,