Semidrying oils absorb oxygen from the air to become very thick, but not hard. Cottonseed, corn, and sesame oils are of the semidrying type. Olive, peanut, and grape-seed oils, butterfat, and lard are examples of nondrying types. Volatile oils, also called essential oils, evaporate quickly, especially when heated. Some of these oils come from plants, and others are artificially created.
People use volatile oils chiefly for their flavor or odor.
The taste of such food flavorings as lemon, mint, and vanilla extracts results from the volatile oils they include. Volatile oils also flavor chewing gum, tobacco, and toothpaste. Most fine perfumes include fragrant oils obtained from roses and other flowers. Manufacturers use such volatile oils as lemon oil to give a scent to soaps and other cleaning products. Natural volatile oils are extracted from various parts of plants, including bark, flowers, leaves, roots, seeds, and twigs.