Key Lime Pie From America

Key lime pie is an American dessert made of key lime juice, egg yolks, and sweetened condensed milk in a pie crust. The traditional Conch version uses the egg whites to make a meringue topping. The dish is named after the small Key limes (Citrus aurantifolia 'Swingle') that are naturalized throughout the Florida Keys. While their thorns make them less tractable, and their thin, yellow rinds more perishable, key limes are more tart and aromatic than the common Persian limes seen year round in most U.S. grocery stores.

Key lime juice, unlike regular lime juice, is a pale yellow. The filling in key lime pie is also yellow, largely due to the egg yolks.

During mixing, a reaction between the condensed milk and the acidic lime juice occurs which causes the filling to thicken on its own without requiring baking. Many early recipes for Key lime pie did not require the cook to bake the pie, relying on this chemical reaction (called souring) to produce the proper consistency of the filling. Today, in the interest of safety due to consumption of raw eggs, pies of this nature are usually baked for a short time. The baking also thickens the texture more than the reaction alone.

The origin of key lime pie has been traced back to the late 19th century in the Key West, Florida area. Its exact origins are unknown, but the first formal mention of Key lime pie as a recipe may have been made by William Curry, a ship salvager and Key West's first millionaire; his cook, "Aunt Sally", made the pie for him. If such is the case, however, it is also possible and maybe even probable that Sally adapted the recipe already created by local sponge fishermen. Sponge fishermen spent many contiguous days on their boats, and stored their food on board, including nutritional basics such as canned milk (which would not spoil without refrigeration), limes and eggs. Sponge fishermen at sea would presumably not have access to an oven, and, similarly, the original recipe for Key lime pie did not call for cooking the mixture of lime, milk, and eggs.

Key lime pie is made with canned sweetened condensed milk, since fresh milk was not a common commodity in the Florida Keys before modern refrigerated distribution methods. The creator of the "frozen" Key lime pie is Fern Butters (1892-1975).