Star anise

Star anise is the fruit of a small evergreen tree that grows up to about eight to fifteen metres, with aromatic leaves and fragrant flowers. The fruit is a star of typically eight woody, boat-shaped segments called follicles that radiate from a central point. Each segment splits open when dry to reveal one glossy, reddish-brown seed. The fruit and seed contain anethole, the same aromatic compound that gives anise and fennel their liquorice flavour, and star anise has a warm, sweet and slightly bitter taste.

Illicium verum is native to south-western China and northern Vietnam, and is grown commercially in southern China, Vietnam, Laos, India and Indonesia. Guangxi province in China is a major source. The tree prefers a warm, humid climate and takes about six years before bearing fruit, then can yield for decades. It is important not to confuse it with Japanese star anise, Illicium anisatum, a related and toxic species that is not used in food. Fruits are harvested before they fully ripen and sun-dried.

Star anise has been used in China for many centuries as a culinary spice and in traditional medicine, and is a key component of Chinese five-spice powder. It travelled westward along trade routes and reached Europe by the late sixteenth century, apparently through Asian traders and the British explorer Thomas Cavendish. In Europe it came to be used as a cheaper substitute for true anise in liqueurs and sweets.

Star anise became well-known in global pharmaceutical history as the industrial source of shikimic acid, used in the production of the antiviral drug oseltamivir, which led to temporary supply concerns during flu outbreaks. Today it remains essential to Chinese, Vietnamese and Indian cooking, in dishes such as pho, braised meats and masala chai, and in anise-flavoured spirits.

Whole pods are simmered in broths, braises and stocks, such as Vietnamese pho and Chinese red-braised pork, and removed before serving. Ground star anise appears in five-spice powder, garam masala blends and spice rubs. It flavours mulled wine, chai, poached fruits, pickling brines and baked goods, and gives a liquorice note to liqueurs such as sambuca and pastis. A little goes a long way, and whole pods keep their aroma well when stored airtight.

In culinary amounts, star anise adds flavour with negligible calories, plus trace minerals. The pods contain essential oils, mostly anethole, and shikimic acid, a compound used industrially in drug manufacture. Star anise is traditionally used in Chinese medicine for digestion, though evidence for health claims from small culinary amounts is limited. It is best seen as a flavourful spice that lets cooks reduce reliance on sugar or salt.