FRESH LIME JUICE has a bright, acidic taste and distinctive aroma. Its flavour is more complex than that of lemon: more perfumed and fragrant. The fruit is most popular in the cuisines of Southeast Asia, Latin America and the Caribbean, where its juice is frequently combined with chillies and garlic to brighten and temper the spice and strength of those aromatics. In Southeast Asian dishes it tones down the pungency of fish sauce.
There are many varieties of limes and they range in flavour from the sharp and sour that most of us are familiar with to milder limes. In North America, the most common lime is the large Persian variety, while the distinctive pale-yellow Key lime is irreplaceable in the famous Key lime pie of Florida, which is made only with lime juice, condensed milk and egg yolks.
In Hong Kong, three varieties are available: Persian, Thai (smaller, rounder and juicier than the Persian), and the kaffir lime. The latter is misshapen, bumpy and wrinkled - it is almost the shar pei of limes. If you can ignore its ugly appearance you'll find that although there is not much juice, the fruit is sour and intensely aromatic. The leaves of the kaffir lime are a flavouring in their own right. You've probably seen them in Thai curries and soups, either whole or finely julienned. Although these leaves are rather tough, they impart a strong citrus aroma and flavour.
Because lime juice is so sharp it makes a great palate cleanser. For a fancy dinner party, try making a lime sorbet or granita from the Persian or Thai varieties and serve small portions as an intermezzo between the fish and meat courses. Lime sorbet (in bigger portions) also makes a light, refreshing dessert after a rich and heavy meal. Lime zest adds another dimension to sable or shortbread cookies when finely grated and mixed into the doughs.
Lime also adds a delicious tang to summer drinks. When I was in college we often made fake lime margaritas, daiquiris or gimlets by taking a partially thawed can of frozen 'limeade' concentrate and mixing it in the blender with ice cubes, tequila (for margaritas), rum (for daiquiris) or vodka (for gimlets). Take care: these drinks are dangerous because the strong lime flavour hides the taste of alcohol. For a more innocent drink, make Thai lime sodas by mixing fresh lime juice with cold seltzer water and a little sugar syrup to taste.