Key Limes are very small and round, about the size and shape of a large walnut or ping pong ball. They are smaller than Persian Limes, have thinner, lighter green skin, and have more seeds. In compensation, their sour flavour is more intense and fragrant and they are very juicy — they are about 40% juice.
They grow on thorny evergreen trees which are not very frost tolerant.
Most Key Limes don’t in fact come from the Florida keys. Over 90% come from Mexico and other spots in Central America.
Many people say that Persian Limes aren’t a good substitute for Key Limes, as the flavour is weaker. While that is definitely true, this is the substitute section here, and this is no place for petulance. It would have been nice if you could have got Key Limes, but losers can’t be choosers. Substitute any Lime your can get your hand on, or bottled Lime juice, or lemon, or vinegar (if the purpose is just a souring agent). When swapping in Persian Limes for Key Limes, use a bit more Lime juice to compensate for the weaker flavour, and cut back accordingly on other liquid.
1 medium-sized key lime = 1 1/2 tablespoons of juice and 1/2 tablespoon of zest / grated peel
18 – 20 Key Limes = 1 pound / 450g
2 tablespoons key lime zest = 5g key lime zest
Key Limes were extensively grown in Florida until they were wiped out by a hurricane in 1926, at which point the orchards were replaced with Persian Lime trees as they are easier to grow, pick and ship.
“Limau nipis” is the Malaysian / Indonesian word.