A bitter variety of the orange fruit that has a flattened appearance and rough, thick skin. The flesh contains numerous seeds and provides a bitter taste if eaten. Seville oranges are generally not eaten out-of-hand because of their acidic taste but are more often used for cooking due to their strong orange flavor. They are popular for making marmalades, jellies, and jams, flavored liqueurs, and are used to enhance the flavor of marinades. Mostly grown in the Mediterranean regions, the Seville Orange has a short growing season so they are not always readily available. It is a variety that may also be referred to as Bigarade oranges.
For recipes requiring a bitter or sour orange, a subsitution may be required since these oranges may not be readily available. Use equal parts of orange and grapefruit juice or use 2 parts orange juice combined with 1 part lemon juice and 1 part lime juice.