Citrus is a variety of flowering shrubs and small trees that yield fruit that contain a high quality of citric acid. They are a good source of vitamin C, but the citric acid gives that a very sharp and sometimes sour taste.
Lemons and limes are mostly used for their juice, but their zest or grated outer skin adds flavor to many cooked dishes. Be careful not to zest too deeply as you will get some of the pith or white membrane, which is very bitter. Lemons and limes are also widely used as a garnish for entrees and also for cocktails. On a hot summer day, many a family will serve a pitcher of iced lemonade as an afternoon treat. In the days of wooden sailing ships, the British navy rationed limes to sailors stave off scurvy. This is why sailors were referred to as limeys.
For breakfast, grapefruits are commonly cut in half and eaten out of its skin with a spoon. Grapefruit wedges are added to fruit cups and first class restaurants serve a half of a grapefruit broiled with brandy as a dinner appetizer. Grapefruit juice along with orange juice are a common breakfast beverage.
One of the most popular citrus fruit is the orange, whose family ranges from the small Kumquat to the large Navel orange. The small orange kumquats are featured on many relish tables or used as a entree garnish. Navel oranges, tangerines and clementines are often added to a brown bag lunch as a fruit that is easy to peel and eat.
In cooking, oranges are used in glazes for vegetables like beets and carrots or sauces for entrees like chicken. Duck is usually served with an orange based sauce called Bigarade. Oranges are also used as a flavoring for frostings and in cake, cookies, bread, custards and chiffon pies. Mandarin oranges, which can be found canned, are used in several salads. Serville oranges, which are bitter, are used for confections or candied orange peel.
Two very expensive desserts that are served in fancy restaurants are the whole mandarin orange and the Clementine, which have had lots of simple syrup and vodka inserted into them before they are poached and the Crepe Suzette. Any restaurant that features table-side cooking will be proud to offer this delicious crepe dish cooked with orange zest and the orange and cognac liqueur called Grand Marnier.