All You Need to Know About Limes & Key Limes

If there’s a dessert that sums up Florida, it’s our key lime pie. 

The key lime plays a large role in the culinary culture here in Southeast Florida — put it in pies, in drinks, on tacos or in lemonade and it adds a fresh burst of zingy acidity that makes any dish better. 

Here’s all you need to know about the key lime and how it’s different to your regular everyday limes. 

What’s a key lime, anyway?

What makes a lime, a lime?

The best place to start when describing a lime is to begin with citrus fruits, since that’s what nearly all limes are.

The Citrus genus is a group of flowering evergreen shrubs and trees that almost always showcase strongly-scented, 4-5 petaled white flowers. Their fruits have a peel with a pith surrounding segments of juice-filled vesicles high in citric acid and vitamin C, and aside from the genetically-modified varieties, they all have seeds inside the center. 

Sure, this all sounds a little boring and unrelated, but these characteristics are important to keep in mind as we discuss the many varieties of limes out there! A hint: not all of them are limes!

A real, true, bona-fide lime is a member of the citrus family — though they’re not a naturally-occurring species.

Citrus limes, like the majority of citrus fruits, are hybridized from five original citrus species: the citron (a larger, thicker-skinned lemon), the pomelo (a large, grapefruit-like fruit), the mandarin orange (a smaller tangerine), the small-flowered papeda (a small, sour fruit native to the Philippines) and the kumquat (a small, olive-sized orange). 

The first three species are considered to be the mothers of all citrus fruits in the world, while the last two play larger roles in the hybridization of limes. It’s actually really interesting to dive into the family tree of citrus fruit, since you can see how varieties like the blood orange, sour orange, meyer lemon, grapefruit and tangelos are related to each other! 

Anyway, back to limes. 

Like we said, a true lime is a citrus fruit that descends from one or a few of the original citrus varieties. Interestingly enough, limes aren’t even naturally green — they are picked while they’re still green, but they will turn yellow if left to ripen on the tree!

Depending on which species it's related to, the lime will have different sizes, skin thickness, acid levels and harvest schedules. That’s where all the different limes come in!

What makes a key lime unique?

Looking at the lime family tree, a key lime is a mix of a citron and a papeda. Breed the key lime with a lemon (a descendant of the citron, the mandarin, the pomelo and the sour orange) and you’ll get a Persian lime; breed it with kumquat and you’ll get a limequat!

Some characteristics of a key lime include its small, round shape, a thin rind, a strong aroma and a higher acidity. A key lime typically weighs around .75 ounces and contains seeds, unlike the more common Persian limes found in grocery stores. It takes about 20 key limes to get one cup of lime juice, so they’re pretty small!

Key limes are named for the Florida Keys where they became a key crop in the late 19th century. Prior to that, key limes were actually called Mexican limes, since that’s where they were introduced by Spanish explorers carrying the seeds from the Mediterranean. Originally, the key lime’s ancestors were native to Southeast Asia. 

Despite the limes’ popularity in Florida, they’re no longer the most popular lime grown in Florida since a deadly storm wiped out nearly all the key lime crops back in the 1920s. Farmers replaced the key lime with the stronger, hardier, seedless Persian lime that’s become the de-facto lime of supermarkets since. 

The key lime is also known as the Mexican lime, West Indian lime, Omani lime or bartender’s lime. However, it’s best known for featuring in the famous Floridian tart — the key lime pie!

Different kinds of limes

Here are a few other kinds of limes out there that may seem interchangeable with our key lime, but are entirely unique species on their own!

Persian lime

Persian limes — also known as Tahitian limes — are the limes most commonly found in U.S. grocery stores. They’re the most popular and the most widely-produced lime in the world, and are especially valued for their size, their juiciness, their zest and their seedlessness.

Australian limes

Several naturally-occurring species of lime fall under the category of Australian limes.

• The desert lime
• The New Guinea wild lime
• The large leaf Australian wild lime
• The Mount White lime
• The caviar lime/Australian finger lime 
• The dooja/round lime/Australian lime

Most of these limes are small, oblong and found in forested regions between Australia and Papua New Guinea. There are also a number of cultivars made by hybridizing and mutating these species, with uses ranging from edibility, decoration and landscaping!

Makrut lime

Also known as the Kaffir lime or Thai lime, this species is one of the top three most widely produced limes in the world, though its popularity lies largely in Southeast Asia. It’s small and round with a thick, wrinkly rind. 

Philippine lime

Also known as a calamansi, calamondin or Philippine lemon, this lime is a hybrid of the mandarin orange, the tangerine and the kumquat. When ripe, it has an orange pulp and a thin orange peel that resembles a smaller, rounder tangerine. Though it ripens to orange on the tree but can be harvested while green, too — either way, it’s sour and acidic and great for marmalades, seasonings, marinades and drinks. 

Rangpur lime

This hybrid of the citron and the mandarin orange is a common substitute for limes thanks to their high acid levels. However, unlike other limes, the Rangpur lime is not related to the small-flowered papeda, so technically it’s more of a sour citrus than a true lime. 

Sweet lime

Sweet limes and sweet lemons are similar to non-sweet limes and lemons, but with a little less citron and a little more mandarin ancestry.  In fact, several fruits fall under this category!

• Limetta: this small, round Key-lime-like fruit has a sweet juice
• Lumia: looking more like a lemon, this pear-shaped yellow fruit is a little less sweet than the limetta
• Palestinian sweet lime: this small, round, Meyer lemon-like fruit is still a little sour and is used as a substitute for other limes. It’s main use, though, is as a rootstock for other citrus fruits.

Limequat

Bred with key lime and kumquat fruits, this small lime has a sweet skin and sour pulp that’s high in vitamin C. The limequat is small and sweet enough to be eaten whole, but it can also be used to flavor drinks or season dishes.

Non-citrus limes

There are plenty of fruits out there that call themselves limes, but that are not technically within the citrus family. 

Wild lime, which is a type of flowering plant found around Florida, isn’t actually a lime. Although it smells and looks like a lime tree, the non-fruiting shrub is only closely related to the citrus family.

The Spanish lime is another lime pretender. The round, green edible fruits certainly resemble limes, but the fruits contain stones, not seeds, and an orange, gelatinous flesh.

Who knew there was so much to learn about limes, huh? It really makes you appreciate the key lime, its limequat offspring and its fascinating family tree!

If you live in our luxury Florida apartments, then be sure to get your hands on some key limes next time you’re at a farmers market or local grocery store. You’ll be surprised how different they are to a Persian lime, now that you’re a bona-fide lime expert! 

Enjoy!

Pin it!

Featured photo by Nathan Lemon on Unsplash