While there are several varieties of this Vitamin C-heavy fruit, the two most commonly available in the United States are Persian limes and Key limes.
When you think of limes, chances are you picture Persian limes. These oval-shaped, smooth-skinned bright green fruits are the most common variety found at grocery stores.
Shop: Persian limes are available year-round. Look for brightly colored fruit that feels heavy for its size. Persian limes should feel hard when squeezed. A few brown spots won’t diminish the flavor, but avoid limes with hard, shriveled skins. Limes that are yellowish are still edible, but will not be as tart as fresh ones.
Store: Whole limes can be stored in a plastic bag in the refrigerator for up to 10 days. Once limes are sliced, they will keep in the fridge for up to 5 days.
Use: Use lime wedges as garnishes. Squeeze the juice over fish. Lime juice can also be used in drinks, pies and frozen desserts. Lime peel is good used in marmalade.
Key limes (also known as Mexican limes) are smaller than Persian limes—think golf ball to ping pong ball-size—round in shape and yellow in comparison. They have more seeds, and are more sour tasting than Persian limes.
Shop: Key limes can be difficult to find, we suggest searching gourmet markets. Select smooth, firm fruit that is heavy for its size. As an alternative, key lime juice can be found in the canned fruit aisle.
Store: Store Key limes in a plastic bag in the refrigerator for up to a week.
Use: Without a doubt, Key limes are most often used to make Key lime pie. But they can also be used similarly to Persian limes - for marinades, as garnishes, in sauces, etc.
What's the Real Difference?
Key limes are much smaller in size. They contain more seeds and are yellowish-green in color. They have a bitter tartness that makes their taste unique. Persian limes are far more common and are easy to find in any grocery store, while key limes are generally restricted to gourmet markets.
Key Lime Substitute
Whenever possible, key limes should be used when called for in a recipe. Otherwise the flavor will not have the intended results. However, this juice substitute works in a pinch:
Key Lime juice substitute = 1/2 Persian lime juice + ½ lemon juice