Infusion
Infusion is the process of extracting chemical compounds or flavors from plant material in a solvent such as water, oil or alcohol, by allowing the material to remain suspended in the solvent over time (a process often called steeping). An infusion is also the name for the resultant liquid. The process of infusion is distinct from decoction, which involves boiling the plant material, or percolation, in which the water passes through the material (as in a coffeemaker).
History
The first recorded use of essential oils was in the 10th or 11th century by the Persian polymath Avicenna, possibly in The Canon of Medicine.
Tea is far older than this, dating back to the 10th century BC as the earliest recorded reference.
Preparation techniques
An infusion is a very simple chemical process used with botanicals that are volatile and dissolve readily, or release their active ingredients easily, in water, oil or alcohol. The botanicals are typically dried herbs, flowers or berries. The liquid is typically boiled (or brought to another appropriate temperature) and then poured over the herb, which is then allowed to steep in the liquid for a period of time. The liquid may then be strained or the herbs otherwise removed from the liquid. Unless the infusion is to be consumed immediately, it may then be bottled and refrigerated for future use.