The fruit is knobbly and fragrant, and the peel is great grated in anything you'd used lemon or lime rind in. The juice is also good too, but there is very very little and it is resistant to being removed from the fruit, though a couple of seconds in a hot oven or microwave makes it much easier.
Kaffir limes are supposed to be very very tropical indeed. I was given one about seven years ago, and planted it a bit dubiously, but it has never taken any notice of the frost at all - if anything it's more cold resistant than the tahitian limes, which are slightly more cold resistant than the lemons.
Kaffir limes are smallish trees, especially in cold areas- I doubt ours will grow over 2 metres, and it is a very very slow grower here. They aren't particularly attractive, but not ugly either - just green green and green. And they are also pretty thorny.
Kaffir lime leaves can be dried, but usually aren't as they rot easily. They are best dried indoors, in a dark spot. Try leaving them on blotting, computer or brown paper (ie porous, not waxed) in the roof cavity, as long as it isn't inhabited by possums or rats. Or tie up as single branches and hang from the ceiling. The leaves should be green, not yellow when dried, with no brown or black patches. If they're yellow, throw them out, as the taste will be affected. Just break off the brown patches and throw them away before use.
Add kaffir limes leaves to chicken stock for a good warming soup. Add to laksas, curries, or shred young leaves very very finely in salads.
They are also good added to borsht, and a whole fish cooked on a bed of lime leaves is a delight, as are roast chooks. Also good slipped into cold drinks, or keep a jug of lime leaves and water in the fridge. Finely shredded young leaves are also good in stir fried dishes.
The kaffir lime leaves are a very popular spice in Thailand; their characteristic flavour appears in soups, stir-fries or curries (see coconut for a list of other ingredients to Thai curries). In Thai cuisine, kaffir lime is frequently combined with garlic, galanga, ginger and fingerroot, together with liberal amount of chiles. Fresh Thai basil is needed for the authentic fragrance.
A Thai dish most popular in Thailand and among foreigners is tom yam (also spelt tom yum , a fiery-hot, sour and very aromatic soup prepared from shrimps (tom yam gung , chicken (tom yam gai or fish (tom yam pla The soup is flavoured with loads of chiles, lime juice, fish sauce and fresh spices: galanga, lemon grass and kaffir lime leaves. It is served topped with aromatic greens, usually basil (horapha) or coriander.
A related soup is tom khaa, which contains more galanga and is less spicy due to a splash of coconut milk added. Similar soups are prepared in other South East Asian countries; see rice paddy herb for a Vietnamese example.
Kaffir lime leaves are also popular in the West of Cambodia, but less so in Vietnam. Malay and Indonesian (especially, Balinese; see also Indonesian bay leaf) cuisines use them sporadically for chicken and fish.
Kaffir lime has a very strong, characteristic fragrance that cannot easily be substituted by other spices; lemon myrtle leaves or simply lime peel is probably the best substitute. Dried leaves lose their flavour within a year; therefore, they are better kept frozen.
The fruit juice, which is very sour and has the same fragrance as the leaves, is sometimes added to fish or poultry dishes in Malaysia or Thailand. Less commonly, it is also used in Indonesia. For a summary of sour spices, see mango.
