A zester is a kitchen tool used to remove the outer zest of citrus fruits like lemons, limes, and oranges. The zest is the colorful outer layer of the peel, which contains aromatic oils that add flavor to dishes. Zesters typically have a handle and a metal blade with small, sharp holes that scrape off the zest without cutting into the bitter white pith underneath. Zesters can also be used to grate other ingredients, such as cheese or ginger. They are often made from stainless steel for durability and easy cleaning. This tool is popular among chefs and home cooks for enhancing the taste of both sweet and savory recipes.