This sour, zesty citrus fruit loves tropical climates. Leading lime producing countries include the US, India, Italy, Mexico and Spain. Key limes are smallish, nearly spherical, thin-skinned fruit often containing only a few seeds. Oval-shaped Persian limes (also known as Tahitian limes) have thicker skins. Kaffir lime leaves are a key ingredient giving Thai cooking its distinct flavour.
Choose brightly coloured, smooth-skinned limes that feel heavy for their size. They should have a little give, and not be rock hard. Small brown areas on the skin won’t affect the juiciness or flavour.
Limes kept at room temperature will last for up to one week. Loosely wrapped limes kept in the fridge can last for up to one month. Bag and refrigerate lime slices or wedges for up to five days. To store lime juice, pour the juice in ice-cube trays, transfer frozen cubes to sealed bags and freeze for up to four months. Leaves and lime zest can be frozen for one year or more.
Citrus fruits contain a good amount of vitamin C, but they also contain other antioxidants, vitamins and minerals. Studies have shown higher intakes of citrus can have a protective effect against some cancers, as well as being associated with a reduced risk of coronary heart disease and stroke.
To extract juice, bring limes to room temperature and roll the fruit on a hard surface to break the juice sacs. Or let limes sit in hot water for a few minutes to soften. When cooking with limes don’t use an aluminium pan: the acid reacts with the metal which can give an off-flavour and a grayish colour. To ensure the sour flavour remains intact, add lime juice towards the end of cooking unless the cooked dish has lime as a background flavour. See Mixed meat spicy salad for a lime-enhanced Thai-style recipe. To reduce salt in your diet, try lime juice – it works well as a seasoning replacement.
Dark green kaffir lime leaves add great flavour to soups, salads, curries and stir-fried dishes – just remember to remove whole leaves before serving (alternatively, add finely sliced leaves). See Lamb and eggplant curry for a recipe with kaffir lime leaves.
Did you know? Ripe limes are yellow but they are picked from the tree as immature green fruit – perhaps to distinguish them from lemons and to retain the acidity that marks their strong tart flavour.