What are Bitter Oranges?

Bitter oranges are members of the orange family which are cultivated for their intensely sour, bitter fruit and fragrant peels. While the bitter orange is rarely used as a standalone item in food, products of the fruit are integrated into things as varied as tea and marmalade. Like many other citrus fruits, bitter oranges prefer semi-tropical climates, and tend not to do well in cooler areas, although they are sometimes grown ornamentally in temperate zones. Bitter oranges are rarely available for sale in markets, although products such as bitter orange extract are sometimes sold.

Alternate names for the bitter orange include sour orange and Seville orange, after a Southern Spanish city in Spain. A variant on the bitter orange, the bergamot orange, is actually a subspecies of Citrus aurantium, the botanical classification for the bitter orange. In any case, bitter oranges are characterized by an intensely bitter flesh which is generally viewed as unpalatable on its own. The citrus fruit appears to have originated in Vietnam, where the spiny evergreen trees have been cultivated for hundreds of years.

In Asian cuisine, the bitter flavor is valued as an addition to foods. Often, bitter oranges are pickled for use as a garnish. Outside of Asia, the bitter oranges are cultivated for use as a botanical extract. Bitter orange oil is often used in cosmetics, and is sometimes included in health supplements as well. The peels and fruits may be candied for inclusion in sweets and desserts, and the bitter flesh is added to marmalade and other preserves for an injection of sour flavor. Bitter orange extract is also a crucial ingredient in triple sec and Curacao, two classic liqueurs.

The Bergamot orange is a variant cultivated in Italy for its flavorful and zesty peels. Bergamot is a classic ingredient in Earl Grey tea, and it is also used in other foods. The fruit of the Bergamot orange has a distinctive pear shape which sets it aside from bitter oranges. A true bitter orange has an oblate shape.

The bitter orange tree is famously very hardy, and it is sometimes used as rootstock as a result. When bitter oranges are used as rootstock, they are pruned to a single trunk, allowing gardeners to graft another orange varietal onto the trunk. The bitter orange rootstock can withstand cold, poor water, and insect invasion more effectively than some more palatable orange species, making it a good choice for citrus trees destined for beginning gardeners.