Cultivated for thousands of years in the Indo-Malayan region, the key lime (also known as "Mexican lime" and "West Indies lime") has long been treasured for its fruit and decorative foliage. Smaller and with more seeds than the more common Persian lime, its distinctive flavor makes it heavily sought after, especially for delicious desserts. Key lime is most often used for its juice, which is sweet and tart and a signature ingredient in key lime-based desserts, marinades, and cocktails.
A key lime is a hybrid citrus hybrid fruit that is spherical and measures about 1 to 2 inches across. It is green when picked but becomes yellow when ripe. A ripe key lime feels heavy for its size. Compared to a Persian lime, it is a smaller and has more seeds to remove, higher acidity, a stronger citrus aroma, and a thinner rind. The key lime is valued for its unique flavour.