A zester is a kitchen tool used to remove the outer layer of citrus fruits, such as lemons and limes, to create fine shavings of zest. This zest contains essential oils that add flavor and aroma to various dishes, including desserts, marinades, and cocktails. Zesters typically have a small, sharp blade or a series of holes that make it easy to scrape the skin without removing the bitter white pith underneath. Zesters come in different designs, including handheld versions and those that resemble graters. They are often made from stainless steel for durability and easy cleaning. Using a zester can enhance the taste of recipes by incorporating fresh citrus flavors, making it a valuable tool in any kitchen.