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. An infusion is also the name for the resultant liquid. The process of infusion is distinct from both decoction—a method of extraction involving boiling the plant material—and percolation, in which water is passed through the material.

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

Infusion is a chemical process that uses botanicals that are volatile and release their active ingredients readily in water, oil, or alcohol. In this process, a liquid is typically boiled and poured over the herb. After the herb has been allowed to steep in the liquid for an appropriate period of time, it is removed leaving an infusion. Unless the infusion is to be consumed immediately, it is bottled and refrigerated for future use.
The amount of time the herbs are left in the liquid depends on the kind of infusion. Infusion times can range from seconds to hours, days, or months.
There are several accessories and techniques for removing the steeped or leftover botanicals that were used to infuse liquids, including metal steepers, tea infusers, and french presses. The most commonly used technique is the teabag, which is made with filter paper and filled with various tea flavors.

Examples

A common example of an infusion is tea; most varieties of tea call for steeping the leaves in hot water, although some variants call for decoction instead. Many herbal teas are prepared by infusion, as well; lemon, chamomile, senna, apple, ginger, rooibos, and many other plants are used individually or in combination. Herbal infusions in water and oil are both commonly used as herbal remedies. Coffee can also be made through infusion, but is more often made through percolation.
Plants with desirable flavors may be steeped in an edible oil or vinegar for an extended period; the infused oil or vinegar is often sold still containing the plant and is then used as flavoring. Chilis, lemon, garlic, and many other plants may be used. There can be ambiguity in the labeling of these oils: for example, what is described as sesame oil may be oil extracted from sesame seeds or another vegetable oil infused with sesame.