Traditionally, this pie is made from the juice of the Key lime, a small yellow citrus fruit quite different from the larger and more familiar Persian lime. Key limes are very sensitive to cold and in the U.S. have never been grown above the very southern tip of Florida. Bad weather and disease have killed off so many of them that the only remaining grove is a private one on one of the Keys, so you cannot buy Key lime juice in the U.S. any more. Key limes are still grown widely in South America and probably elsewhere on other continents.
There is something called "Key West lime juice" sold in pint bottles which everybody uses instead now, which seems to be regular lime juice slightly concentrated. It's widely available in Florida and occasionally elsewhere in the U.S. It's also available via mail order from Key West Aloe, telephone +1 305 294 5592 or 800-327-5866. In a pinch, you can substitute regular lime juice, though it doesn't produce quite the bright yellow custard that traditionalists like. You may have to use extra juice, because Persian limes are less acidic than Key limes.
John Levine Interactive Systems Corp, Boston, Massachusetts, USA email@example.comRecipe last modified: 3 Jan 88
Path: decwrl!recipes From: johnl@ima.ISC.COM (John R. Levine) Newsgroups: alt.gourmand Subject: RECIPE: Key lime pie Message-ID: <14254@decwrl.DEC.COM> Date: 29 Jul 88 05:33:54 GMT Sender: recipes@decwrl.DEC.COM Distribution: alt Organization: Interactive Systems Corp, Boston, Massachusetts, USA Lines: 82 Approved: firstname.lastname@example.org Copyright (C) 1988 USENET Community Trust Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct commercial advantage, the USENET copyright notice and the title of the newsgroup and its date appear, and notice is given that copying is by permission of the USENET Community Trust or the original contributor.