Lime Vs Key Lime: What's The Difference?

What are Persian limes?

Persian limes (also called Tahiti limes, Citrus latifolia) are the most common limes in American grocery stores, accounting for about 95 percent of US lime production. They're larger than Key limes (1.5-2 inches in diameter), with thicker, more durable skin, oval shape, and mild lime flavor. The juice is moderately tart with subtle floral notes. Persian limes are typically seedless or nearly so. Most commercial Persian limes come from Mexico, with smaller amounts from Florida and California. They're typically harvested green but can ripen to yellow on the tree (though commercial fruit is picked green for shipping). The thicker skin and durability allow Persian limes to ship and store well; they last 1-2 weeks at room temperature or up to a month refrigerated. They're used in cocktails, ceviche, Mexican cuisine, marinades, and any dish needing lime juice.

What are Key limes?

Key limes (Citrus aurantiifolia, also called Mexican limes or West Indian limes) are smaller, more aromatic limes named for the Florida Keys where they were historically grown. They're about 1-1.5 inches in diameter (golf ball-sized), more spherical, with thinner yellow-green skin and abundant small seeds. Each Key lime yields significantly less juice than a Persian lime (about 1 tablespoon vs 2-3 tablespoons), making recipes call for more Key limes when used. The flavor is more intense and aromatic than Persian limes, with brighter tartness and complex floral notes. Most US 'Key limes' are actually grown in Mexico (Persian Key limes are essentially gone from Florida after Hurricane Andrew in 1992 destroyed commercial groves). Key limes are essential in authentic Key lime pie, and popular in Mexican and Caribbean cuisines.

How do Persian and Key limes compare?

Size differs noticeably: Persian limes are 1.5-2 inches; Key limes are 1-1.5 inches. Shape differs: Persian limes are oval; Key limes are more spherical. Seed content differs: Persian limes are nearly seedless; Key limes have many small seeds. Skin differs: Persian limes have thick green skin; Key limes have thin yellow-green skin. Juice yield differs: Persian limes give 2-3 tablespoons per fruit; Key limes give about 1 tablespoon. Flavor differs: Key limes are more aromatic, tart, and complex; Persian limes are milder. Availability differs: Persian limes are widely available year-round; Key limes are seasonal and harder to find outside Florida and Latin markets. Shelf life differs: Persian limes last 2-4 weeks; Key limes last 1-2 weeks. Price differs: Key limes cost more per lime and more per ounce of juice.

Can you substitute one for the other?

Yes, with adjustments for quantity and flavor intensity. To substitute Persian limes for Key limes: use about half the number of limes (since Persian limes have 2-3 times more juice each); the result will be slightly milder. To substitute Key limes for Persian limes: use 2-3 Key limes for each Persian lime; the result will be more intensely flavored. For Key lime pie specifically, real Key limes (or bottled Key lime juice) produce the authentic flavor; Persian limes produce an acceptable but milder pie. Bottled Key lime juice is a common substitute when fresh Key limes aren't available.