onions
Onion oil is, in most cases, one of two related things: the essential oil extracted from an onion, or a base oil such as olive or vegetable oil, which is flavored and augmented by onions, usually during cooking. Essential oils are more common in homeopathic and alternative medicine. In the kitchen, onion oil is almost always intended to provide more flavor than any health benefit.
Onion oil can refer to onion flavored oil.
Medicated onion oil is often packaged in dropper bottles or capsules. The oil is very concentrated and is usually obtained by slowly boiling the onion over time or steam-drying it. Onions naturally contain a lot of moisture, which means that the water must be squeezed or boiled from the vegetable before the oils can be isolated. The process is usually arduous, but not particularly complicated.
Onion oil can be made by boiling onion slices.
Homeopaths sometimes recommend natural onion oil as a treatment for upper respiratory problems, particularly colds and seasonal allergies. It is believed that the oil can help decongest while helping to remove toxins from the body. The oils are also sometimes used to treat ear infections. Some traditional medicine practices prescribe attaching whole onion segments to the body to achieve the oil’s healing properties, but more modern practitioners generally find ingestion or direct application of concentrated oil to be more effective.
Several different pharmaceutical studies also look at onion oil. Most onion varieties are rich in vitamins and disease-fighting nutrients. Researchers tend to look for ways to harness these benefits and channel them into specific treatment regimens for human diseases. Some scientists believe that onion oil can do anything from lowering cholesterol to negating the harmful effects of nicotine and preventing the growth of some types of cancer. The results are largely inconclusive.
In culinary settings, onion oil is often more flavorful, but also less concentrated. Chefs can often extract essential oils from onions simply by heating thin slices of vegetables and then reserving the resulting liquid. Most of the time, flavor is more important than purity. Cooks often add salt and other seasonings and may or may not leave bits of onion to fry while the oil is extracted.
Home-pressed onion oil is often used as a base for many dishes. Oil is a common facet of many recipes. Cooking with onion oil instead of commercial vegetable or corn versions often adds a new layer of flavor to a dish and can enhance a variety of sweet and savory flavors.
Cooks also sometimes create a kind of onion-flavored oil by boiling sliced onions in other oils. Olive oil is a popular choice as its mild nutty flavor can be a good base for spicier onions. This type of oil is popular as a condiment and can also be used to dip breads and vegetables.