Kaffir LimeThe kaffir lime is an evergreen tree, 5–8 metres (16–26 ft) tall, with a broad trunk and thorny branches.
The leaves are strongly aromatic, and the flowers white to off-white. It produces a bumpy fruit that resembles a small Key lime or Indian wild lime; they can be green, ripening to yellow, or more often tinged with red on the side exposed to the sun. The tree is grown commercially for export of its leaves and fruit.
The fruit is used extensively in Thai cuisine. It is also added as a flavoring to dishes throughout Southeast Asia, especially fish and seafood curries such as Vietnamese cuisine's "canh chua", and in Sri Lankan cuisine.
The leaves are usually cooked before use, as their aroma fades upon drying or heating. Giant kaffir lime leaves are used to make a special type of rolled tobacco known as "temple balls" which is smoked by locals in certain regions. Sometimes citrus hystrix is used instead of true kaffir lime in Thai recipes that specify "kaffir lime."
Its essential oil is used in the perfume industry. It was named by Spanish explorer Francisco Pizarro, who found it growing in Peru, where locals called it "pampa lemon." He brought it to Europe, and eventually to Thailand. Its name derives from "kha", roughly meaning "stink" or "smell".
The fruit is relatively acidic - about the same level as Key lime juice. Once fully ripe, it has a strong aroma and flavor. The zest (outermost) layer of the rind contains an essential oil comparable to lime oil with a characteristically strong, sweet odor. The zest of the fruit is used in Southeast Asian cuisine, where it is often used to add aroma to spicy sauces for fish or meat.
The juice and flesh contains citric acid and is also used as a flavoring agent in many foods such as liqueurs such as Triple Sec and Curaçao, in addition to alcoholic beverages such as rum and cachaça. In cooking, the juice is often used for its citric flavor. The juice has a concentrated lime flavor but is sweeter than Key or Spanish limes while the flesh of the fruit tastes more acidic.