Very sharp, acidic citrus fruit rich in vitamin C but with a low sugar content. Used mainly for its juice to flavour drinks, sweet and savoury dishes and as an accompaniment to fish. The aromatic zest or outer rind contains essential oils and is also used as a flavouring. Remove it by grating, using a potato peeler or a zester; take care not to remove any pith with the zest, as it is very bitter.