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The regional table / Florida

Key Lime Pie

Published September 22, 2026 · Florida

A wedge of pale yellow-green lime pie in a graham crust, topped with peaked browned meringue, on a plate with a lime half beside it
The filling is not yellow. Key limes give a pale, almost greenish cream, and anything brighter than this came out of a bottle of food colouring. AI-generated illustration.
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This is a pie built around a can, and the can is not a shortcut — on an island with no pasture, no wells and no ice, it was the only milk there was.

Start with what the island could not do. Jefferson B. Browne's Key West: The Old and the New, published in 1912 and readable in full on Internet Archive, records the town's search for fresh water: "In 1895 the city undertook to secure a supply of fresh water, and an artesian well was sunk in Jackson Square to a depth of two thousand feet," with borings sampled every twenty-five feet and examined for the zoological society of Harvard College. Browne's verdict on the result is five words long: "No traces of fresh water were found." The same book dates the arrival of cold: "Prior to 1890 Key West used natural ice, brought here in sailing vessels from Maine." Browne also notes that for years the mail contractors from Tampa combined carrying the post with "supplying this and the Havana market with beef cattle," which is to say that even the cattle arrived by boat. A place with no groundwater, no pasture and no manufactured ice until 1890 has no dairy herd and no way to keep milk if it had one. That is the condition a pie has to be built for, and it explains the one ingredient people find suspicious: the milk comes out of a tin because for most of Key West's history there was no other kind. What has not been shown here is the date that tin reached the island — the earliest canned-milk advertising found in the Key West Citizen runs on 18 September 1935, under the line "MORE LIKE FRESH MILK THAN ANY OTHER IN CANS," and that is later than the argument needs. Treat the condensed milk as the answer to the island's conditions, not as a dated event.

The lime is documented better than the pie. Florida's Lime and Lemon Industry, a bulletin of the Florida Department of Agriculture published in 1938, gives the Key lime a chapter of its own: "The trees are bush-like in growth and very thorny. The term 'Key' is not a varietal name, but a name given to all limes having identical characteristics, regardless of where they are grown, although in Florida the bulk of them is produced on the Keys." It notes the crop was "restored since the storms of 1926" and that the variety "seems to grow better in that locality than any of the other citrus fruits, the roots readily penetrating the alkaline rock." In a whole bulletin on the state's lime crop the word pie never once appears. The pie is in the newspapers instead, and always under a shorter name. The Key West Citizen of 30 March 1933 reports that "The Busy Bee Bakery is giving away this week either a 9-inch lime pie or a two in one Jig-Saw puzzle with every Betty Crocker Milk Chocolate Cake sold." On 23 December 1938 Fred Auerbach's Restaurant on Fleming Street advertised a $1.50 Christmas dinner ending "LIME PIE PUMPKIN PIE MINCE PIE." And on 15 February 1940 Berlin A. Sawyer wrote in his Island City column that on the keys "lime pie originates off a thorny, green, green tree in your back yard." Not one of them says key lime pie. Nor do they say what was in it: the only dated Florida recipe the search turned up, a "St. Patrick's Lime Pie" in the Clewiston News of 8 March 1940, is a different pie altogether — egg yolks, sugar, a tablespoon of flour, lime juice, grated rind and green vegetable colouring, cooked over very low heat and poured into a baked shell, with no condensed milk anywhere in it. The version below is the island one, and its quantities were worked out for this page.

Why this version works

Yolks in the filling, whites on top. Four yolks give the filling body and a custard's mouthfeel where condensed milk alone is merely thick, and they leave you exactly the four whites a meringue wants. Nothing is bought for the topping and nothing is thrown away, which is how the pie was designed by people who could not run to the shop.

A cooled crust before a cold filling. The graham crust is baked and cooled before the filling goes in. Pour acid-set filling into a warm crust and the butter in the crumbs softens, the base absorbs moisture from below, and the first slice comes out as sand. Ten minutes on a rack is enough.

Acid sets the filling, heat only finishes it. Lime juice thickens sweetened condensed milk on contact, without a crumb of starch or gelatin and without cooking. That is the chemistry the whole pie rests on and the reason it belongs to a hot island: whisk the juice in and you can watch the mixture stiffen in the bowl. The short bake is there to set the yolks and make the filling safe, not to thicken it.

Key limes, not Persians, and not from a bottle. Key limes are small, seedy, thin-skinned and markedly more floral and bitter than the big Persian limes sold everywhere; their juice is paler and their aroma is the whole point. Bottled key lime juice is pasteurised and tastes cooked. If only Persian limes are to be had, use them and accept a rounder, greener, less interesting pie rather than reaching for the bottle.

Ingredient notes

Eggs: four large, separated cold and then left to come to room temperature. Cold whites take twice as long to whip and hold less air; cold yolks seize when the lime juice hits them.

Crust: graham crumbs, butter and a little sugar. The dated record gives no crust at all, so this is a choice rather than a reconstruction; a blind-baked short pastry shell is equally defensible and closer to what a 1930s restaurant kitchen would have had on hand. What matters is that it is baked before the filling meets it.

Key limes: about a pound and a half of them for half a cup of juice, which sounds absurd until you have held one. Roll them hard under your palm before cutting. They are seedy: squeeze through a strainer. Zest before you juice, not after, and take only the green.

Sweetened condensed milk: one 14-ounce can, full fat. Evaporated milk is not the same thing and will not set — it is unsweetened and much thinner. Low-fat condensed milk sets but goes chalky. This is the one ingredient in the pie where there is no substitution worth making.

Step by step

  1. Bake the crust. Heat the oven to 350°F. Mix the graham crumbs, sugar and melted butter until the crumbs hold a squeeze, press them up the sides and across the base of a 9-inch pie plate, and bake 10 minutes. Cool on a rack at least 10 minutes.
  2. Zest and juice. Zest enough limes for 1 tablespoon of fine green zest, then juice them through a strainer to get ½ cup. Do this before you touch the milk, because once the acid and the milk meet you want to be moving.
  3. Whisk the filling. Beat the yolks with the zest for 2 minutes, until pale and slightly thickened. Whisk in the condensed milk, then pour in the lime juice in a steady stream, whisking. The mixture will visibly stiffen in under a minute.
  4. Bake to set. Pour into the cooled crust and bake 15 minutes, until the filling is set at the edges and the centre wobbles as one piece rather than rippling. Cool 30 minutes on a rack.
  5. Make the meringue. Whip the four whites with the cream of tartar to soft peaks, then add the sugar a spoonful at a time and whip to stiff, glossy peaks that hold their shape when the beater is lifted.
  6. Top and brown. Spread the meringue over the warm filling, sealing it to the crust all the way round so it cannot shrink back, and pull it into peaks. Bake 10 minutes at 350°F, until the peaks are browned.
    White meringue being spread toward the edge of pale lime filling in a graham cracker crust.
    Seal the meringue to the crust all around before drawing it into peaks. AI-generated illustration.
  7. Chill. Cool to room temperature, then refrigerate at least 3 hours before cutting. The filling firms as it chills and a warm pie will not slice.
A filling that never set was starved of acid — either the limes were tired or the half cup was short. It cannot be rescued in the plate, but it can be rescued in the bowl if you catch it before baking: whisk in another two tablespoons of juice and watch for the thickening. Meringue that beads amber droplets on top was overbaked, and meringue that weeps a puddle underneath went onto filling that had gone cold; neither is worth remaking, and both taste fine. Weeping is prevented next time by spreading the meringue while the filling is still warm and sealing it right to the crust.

Storage and make-ahead

Keeps 3 days refrigerated, loosely covered. Do not wrap it tightly against the meringue, which sticks to plastic and tears off in sheets.

It freezes, and frozen key lime pie is a legitimate way to eat it rather than a compromise — the filling goes to a dense ice cream. Freeze it uncovered until firm, then wrap; thaw 20 minutes before cutting. A meringue top survives freezing poorly, so freeze the pie plain and whip cream for it on the day.

What to serve with it

It needs nothing, and strong black coffee is the only thing that improves it. If you are serving it after a fish dinner, which is the natural order on the Gulf coast, keep everything before it plain — the pie is sweet, sour and rich in one mouthful and will flatten anything delicate that follows.

A wedge of pale yellow-green lime pie in a graham crust, topped with peaked browned meringue, on a plate with a lime half beside it

From the recipe box / Florida

Key Lime Pie

Condensed milk thickened by lime acid, set briefly in the oven, under a meringue made from the yolks' own whites.

Prep
25 min
Cook
35 min
Total
4 hr 30 min
Serves
8
Calories
430 per serving

Ingredients

Scale

Instructions

  1. Heat the oven to 350°F. Press the crumbs, sugar and melted butter into a 9-inch pie plate, bake 10 minutes and cool.
  2. Zest 1 tablespoon and strain ½ cup of key lime juice.
  3. Beat the yolks with the zest 2 minutes, whisk in the condensed milk, then whisk in the lime juice until the mixture thickens.
  4. Pour into the cooled crust and bake 15 minutes, until set at the edges with a single wobble in the middle. Cool 30 minutes.
  5. Whip the whites with the cream of tartar to soft peaks, add the sugar gradually and whip to stiff glossy peaks.
  6. Spread the meringue over the warm filling, sealing it to the crust, and bake 10 minutes until browned.
  7. Cool, then refrigerate at least 3 hours before cutting.

Nutrition

Fat19 g (10 g saturated)
Sodium230 mg
Protein8 g
Serving1 slice, one-eighth of a 9-inch pie
Calories430
Cholesterol120 mg
Carbohydrates56 g (44 g sugar, 1 g fiber)

Nutrition is an estimate calculated from the listed ingredients and is provided as a courtesy, not as dietary advice.

Questions readers ask

Meringue or whipped cream?

Meringue is what the whites are for, and it is what the old restaurant pies carried. Whipped cream is easier, keeps worse and tastes better cold. If you go that way, whip a cup of cream to soft peaks with a tablespoon of sugar and spoon it on after the pie is fully chilled, never before.

Should key lime pie be green?

No. Key lime juice is pale yellow and the finished filling is cream coloured with the faintest green cast. A vivid green pie has had colouring added — which is not a modern sin, incidentally: the "St. Patrick's Lime Pie" printed in the Clewiston News on 8 March 1940 calls for "green vegetable coloring" outright, and that pie was never pretending to be from Key West.

Can I use ordinary supermarket limes?

Yes, with a change in character rather than a failure. Persian limes give more juice for less work and a cleaner, greener, blunter flavour; key limes are more bitter and more perfumed. Use the same half cup either way. The one thing worth knowing is that Persian limes were the variety Florida nurseries were actually planting by the late 1920s — the 1938 state bulletin records their sales overtaking every other lime combined — so a Persian lime pie is a Florida pie too, just not a Keys one.

Is the filling safe with only fifteen minutes in the oven?

Yes. Fifteen minutes at 350°F brings the centre of a shallow filling past 160°F, which is what the yolks need. The uncooked versions you will read about elsewhere rely on the acid alone and are a different proposition; if you want that pie, use pasteurised yolks and chill it for six hours rather than three.