Have you ever discovered a key lime and wondered how different it is from the common Persian lime? There are two main types of limes you’re likely to come across at the grocery store: the Persian lime and the Key lime.
Persian Limes
Persian limes, or Tahiti limes, are the variety most commonly found in grocery stores and recipes. They have origins in the region of southern Iraq and Persia, which is now Iran.
They have thicker dark green skin, a characteristic oval shape with tapered ends, and are usually 2 to 2 ½-inches wide and 3 to 4 inches long. Persian limes are usually seedless and have light-green to yellow pulp. Persian limes are more acidic than key limes, thus giving them a more tart flavor.
Key Limes
Key limes, also known as Mexican limes or West Indian limes, are small, round, thin-skinned citrus fruits. They are native to tropical Southeast Asia and were first cultivated in the Florida Keys.
Key limes are typically harvested when they are still green and one to two inches in diameter. When ripe, they turn yellow. Ripe key limes should be soft when squeezed, heavy for their size, and green, yellow, or some combination. Key limes are known for being aromatic and typically sweeter in taste. Key limes contain seeds. They are often used for their juice and are a signature ingredient in key lime-based desserts, marinades, and beverages.
Lime Substitution
Persian limes might be the only limes available, depending on where you live. The two limes can easily be substituted for one another, but keep in mind that the flavor profile will be slightly different. Persian limes are more acidic and lack the unique floral and tangy notes that make key limes distinctive. When baked into pie or dessert, many people find it’s very hard to tell the difference between the two.
While fresh key lime juice provides the best flavor, bottled key lime juice can be used as a substitute if fresh key limes are not available. Just be sure to check the label and make sure it’s 100% unsweetened key lime juice.
Selection
Buy smooth, glossy limes that are plump and heavy for their size. Avoid any with dull skin or soft spots. Limes that are past their prime may feel soft and feature brown discoloration on their skin. The flesh will start to dry out, leaving you with minimal juice, if any at all.
Storage
Limes continue to ripen after harvest. The easiest and most effective way to store limes is by keeping them whole. Store Persian and key limes at cool room temperature. Use ripe key limes within two days and Persian limes within five days. Another storage option is to keep them chilled and protected from air in a zip-top bag for up to 4 weeks. Vacuum-sealed bags preserve them for almost 2 months in the refrigerator.
Refrigerate cut lime halves, wedges, and slices in the fridge for five to seven days in an airtight container or a zip-top bag. It’s best to wrap the cut limes in plastic wrap to prevent them from drying out. Freshly squeezed key lime juice can be stored in an airtight container in the refrigerator for up to a week.
For longer storage, freeze lime juice, sliced limes, or whole limes. Frozen juice and limes will keep for three to four months.
Nutrition
Limes, including key limes, are bursting with nutrients. Limes are rich in Vitamin C, antioxidants, and fiber, which can offer health benefits.
Juicing
Key limes require much more work than Persian limes to get the juice out. Key limes are notoriously hard to juice. I would recommend investing in a hand-squeeze citrus juicer. Squeeze the juice into a fine sieve strainer to remove any pulp or seeds.
A Persian lime makes about two tablespoons of juice, while a key lime produces only two teaspoons. It will take 8 regular limes to yield one cup of juice and around 40 key limes to yield the same amount of juice.
Key Lime Dishes
While key limes are predominantly associated with desserts, their unique flavor can also be used in various savory dishes. It complements seafood, particularly fish and shrimp, and is often used in marinades, sauces, glazes, and dressings. Key lime also complements tropical-inspired dishes, salsas, and even guacamole, enhancing the overall taste.
Limes play an essential role in so many of our favorite recipes. Whether squeezing a wedge over fish or making a key lime pie for dessert, it’s always smart to have some of this versatile citrus on hand.
Written by Vicki Hayman, MS, University of Wyoming Extension Nutrition and Food Safety Educator
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