Most folks know Thai lime leaf by its un-politically correct name, kaffir leaf, or kaffir lime leaf. Other names for the citrus are combava, limau purut, daun jeruk perut, makroot (makrut, magrood), chan sác, wild lime, and kieffer lime.
The tree is native to Southeast Asia and Indochina and is commonly used in most of those native cuisines. It should never, ever be called kaffir lime.
Why is it offensive to use the word “kaffir”? Kaffir, kaffer, or kafir originates in South Africa (and other African countries), and is an offensive racial or ethnic slang for Blacks. The base of the word is kafir, an Arabic word that means ‘disbeliever,’ ‘infidel,’ or ‘one who conceals the truth.’
Thai lime leaf, a more descriptive and much less offensive term, refers to the leaves and fruit of Citrus x hystrix, a thorny short tropical tree with “double” leaves (the edge of the leaf forms a figure eight when viewed from above) which have a citrusy, aromatic, and floral-herbal quality. The leaves are used in all manner of S.E.
Asian cooking, in almost every category of dish.
The juice of the fruit is intensely astringent; too sour to use unless it is heavily diluted and sweetened, but the same intense aroma and flavor of the leaf permeates the rind of the fruit, which is prominently used in Thai curry pastes and other regional seasoning pastes.
We are the most familiar with Thai lime leaf when used in Thai cooking, particularly a couple of Thai soups: tom yum (hot and sour
Thai soup), and tom kha (coconut milk and galangal soup). Both dishes feature a combination of Thai lime leaf and lemongrass, two partners that live well together.
To use Thai lime leaf, remove the tough central rib. If the leaves are primarily a seasoning, the de-stemmed whole leaf should be muddled or crushed to release maximum flavor before adding whole to the dish towards the end of the cooking process. In many dishes the leaves are eaten directly after first being cut into a very fine chiffonade or julienne, or being sliced and then pureed or crushed in a mortar and pestle as part of an herbal spice mix.
Again, if added towards the end of the cooking process, the leaves will retain more flavor and aroma. To use the rind for a garnish, grate it very sparingly over the dish after plating, using a very fine microplane zester. One tablespoon of zest from a Thai lime lime is equivalent to about 6 Thai lime leaves. Fresh leaves are preferred, frozen leaves are passable but not desirable, and dried leaves are hardly worth the bother. If you have to use dried leaves, figure on using twice the quantity of fresh, and it still won’t taste like it should.
For fresh leaves, which are incredibly expensive to purchase fresh at the market, the best option is to grow your own. Thai lime trees can handle temperatures down to around 38°F; they are rated as Zone 9 to 10 plants. They require a pot with excellent drainage, filled with a rich, fertile soil with a high humus content.
They are susceptible to root rot anyway, so stick them in a pot that’s too large, and then over-water them, and you can expect them to crater. If you can plant them in the ground, they can get quite large; in a pot they tend to stay more restrained: 6 to 7 feet tall or so.
Ideally the small tree will get full sun most of the day and shade in the afternoon, when the sun is the hottest.
Given enough water, they can grow in full sun in the tropics.
They begin to flower in the winter, bearing white fragrant blooms, which are followed by small to medium-sized aromatic limes with a very bumpy surface.
The potted tree can be kept outside, in a protected spot shielded from winter winds and next to a masonry wall that absorbs heat during the day and gives it off heat night.
When it gets in the high 30’s, either cover it securely to insulate the plant (maybe with a light bulb burning inside the enclosure for extra heat), or move it inside for temporary protection. Thai limes can be susceptible to pests, especially spider mites and scale. Spraying with refined or superfine horticultural oil (similar to dormant oil) usually works well for both pests without affecting the quality of the leaves or fruit.
Mick Vann food is a writer, chef, restaurant consultant, horticulturist whose blog can be seen at http://gustidude.blogspot.com
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