Regular Green Limes are not Key Limes!
Yes, I am one of those people. There are actually very few culinary things I'm persnickety about; however, calling a pie made with regular limes a “Key Lime Pie” is a serious point of contention with me. My family is from Key West. I grew up eating homemade Key Lime Pie from real Key Limes fresh off the tree. Trust me, there is a difference.
Side Note:Key Westers are called “Conchs” /konks/, like the popular and beautiful sea snail shells (See Queen Conch). After the War of Independence Britain began taxing people in the Bahamas on their food produced. These islanders stated they would rather eat Conch than pay taxes, and they did. They developed at least 27 different ways to eat this sea snail that has today risen to delicacy status. Ever since they were called “Conchs”. Settlers from the Bahamas came to the Florida Keys, and that is how those born in Key West are now called Conchs.1
Key Limes are thought to be brought to Florida by the Spanish in the 1500s and were considered naturalized by the 1700s. The hurricane of 1926 wiped out most of the South Florida Key Lime groves, and the Key Lime market from other areas of the world boomed due to demand. While there are still Key Lime trees in Florida, most of them today are privately owned. My parents have both Key Lime and Sour Orange (Seville Orange) trees growing in their yard, as do family members throughout Florida and down in Key West.
1965: Florida State Representative Bernie Papy, Jr. introduced legislation calling for a $100 fine to be levied against anyone advertising key lime pie that is not made with key limes. This bill did not pass.2
While the “Key Lime Tree” grows in many places across the world, and have, since at least the 1990s been mass produced in Mexico, these are not the same as South Florida Key Limes. To say Mexican Key Limes and regular Limes are the same/taste the same as Florida Key Limes would be like saying coffee beans from Hawaii taste the same as coffee beans from East Africa; that is to mean, they don't... at all. If you have a passion for coffee, or say something like chocolate or wine, your pallet knows the difference in the taste of these commodities grown in different regions. Soil acidity, rainfall, and overall climate and soil mineral content affect the flavor of any produce grown.
So what's the difference?
True Florida Key Limes taste the way they do because of their unique growing conditions. While the Key Lime tree is a hardy tree, in that it will grow in most temperate climates, even dry or rocky soil, it thrives in moist, tropical climates. Combine the water-soaked rich soil of South Florida, frequent rains, and a more alkaline soil complexity, and you get the mellow, tart yet slightly sweet, juice-filled Key Lime. A ripe Key Lime is smaller than a regular lime, but Florida Key Limes are plumper and juicier than a Mexican Key Lime due to its growing conditions. If you know what a Sour Orange is, a Key Lime is closest in taste to that. But outside of tropical culinary cuisine not many people are as familiar with the large, bumpy, tart Sour Orange.
Florida Key Limes, when ripe, will also turn a greenish yellow, where as regular limes and those imported from Mexico remain a darker green. Florida Key Limes range in size from that of a walnut to about the size of a ping pong ball. They are round with a much thinner skin than regular limes. A Florida Key Lime is juicier than a Mexican Key Lime, pale yellow in color, and sweeter and less tart than a Mexican Key Lime.
When used to make a Key Lime Pie, the custard part of the pie is also pale yellow in color, due to the egg yolks used, not so much from the color of the juice. Real Key Lime pie does NOT have any jello/gelatin in it, nor is it green! A Key Lime pie is a slightly lighter yellow than a Lemon Meringue or Lemon Icebox Pie. The three main ingredients in a Key Lime pie are fresh Key Lime juice, sweetened condensed milk, and egg yolks. Whether you use a regular pie crust or a graham cracker crust is a matter of personal taste; as is either topping the pie with a baked meringue or whipped cream. Personally I prefer a graham cracker crust and a baked meringue. Allen, however, calls meringue “horse snot” and refuses to eat it.
The History of the Florida Key Lime Pie
1800s: William Curry (1821-1896), a ship salvager and Florida’s first self-made millionaire (commonly referred to as rich Bill), had a cook that was simply know as Aunt Sally. It was Aunt Sally who created the pie in the late 1800s. Some historians think that Aunt Sally didn’t create the Key Lime Pie, but probably perfected a delicacy that was the creation of area fishermen or perhaps was making a Lemon Icebox Pie and used the locally available Key Limes instead of Lemons. William Curry built a lavish mansion for his family in 1855 that still is being used today as the Curry Mansion Inn.3
Historically speaking, the first Key Lime pies were not baked in a oven. Rather, the acid of the Key Limes “cooked” the milk and eggs. However, eggs produced today in the US are meant to be refrigerated because they have had all their protective goop washed off exposing the eggs to rot and bacteria. This is why eggs are now refrigerated in the US. And of course, no matter how you get your eggs, store bought or fresh from the chicken coop, eating “raw” eggs does pose a threat of salmonella. So the pie is now baked.
The texture of a Key Lime pie is more of a creamy custard, not a pudding. Again, this is due to the condensed milk and egg yolks used. Why condensed milk? Well, before the Overseas Highway was built in the 1930s there were no cows or fresh milk in the Keys. Islanders had to rely on cans of condensed milk, which by nature is also sweeter than regular milk. This is why sugar is not needed in the pie either.
Side Note: In Key West, Cafe' con Leche was made with sweetened condensed milk, not milk and sugar. It creates a much sweeter and creamier pairing with the stronger brewed Cuban Coffee.
Many restaurants today feature the popular Key Lime pie. But very few offer true, authentic Key Lime Pie. Most use Key Limes imported from Mexico or other countries. Some use regular limes. Some even use bottled key lime juice, which with many brands contain very little actual juice from key limes. While all these pies are delicious, to someone who grew up on the real, authentic thing direct from a backyard tree in Key West, they flavor completely different. It saddens me to think most people will never get to taste the real thing.
Key Lime Pie
1 – 9inch Graham Cracker Pie Crust (Homemade or store bought) 1 – 14ounce can of Sweetened Condensed Milk 3 – Egg Yolks (reserve eggs whites for Meringue topping) ½ cup Key Lime Juice (fresh, bottled, or frozen then thawed)
Preheat oven to 350°F. Combine milk, egg yolks, and lime juice. Blend until smooth. Pour filling into pie crust and bake for 10 minutes if using a baked meringue top, or 15-20 minutes if using whipped cream or no topping. Allow to stand 10 minutes before refrigerating. After baking you can garnish the pie or the meringue with fresh zest from your Key Lime.
Meringue Topping: 3-4 Egg Whites (room temperature) 1 cup Sugar 3/8 teaspoon
Before starting your meringue , let eggs warm to room temperature. It helps dissolve the sugar and get firmer peaks. Also, wash your metal or glass (not plastic) bowl and mixer to remove any oils that could cause the meringue to fall and place them in the fridge or freezer for a few minutes to get them nice and cold.
In a standing mixer or a bowl with a hand mixer, gently mix in the cream of tartar (optional) before starting to whip the egg whites. Beat the eggs on medium speed until soft peaks start to form. The peaks will curl over when the beaters are removed.
Slowly add in your sugar a tablespoon or so at a time while mixing on high speed until all sugar is incorporated and dissolved. Once you have stiff, glossy peaks you are ready to spread your meringue over your still warm pie. The warmth of the pie helps cook the meringue from underneath and keep it from weeping.
Using the back of a spoon swirl and lift along the top of the meringue to form peaks all across the pie. Place in oven and bake at 350°F for 10 minutes or until meringue is a golden brown. Cool on a baking rack for 10-15 minutes then refrigerate for 4-5 hours before serving.