The lemon (Citrus limon) is a hybrid in cultivated wild plants. The fruit are used primarily for their juice, though the pulp and rind (zest) are also used, primarily in cooking and baking. Lemon juice is about 5% acid, which gives lemons a sour taste and a pH of 2 to 3. This makes lemon juice a cheap, readily available acid for use in educational science experiments. Both lemons and limes are regularly served as lemonade or limeade, its equivalent, or as a garnish for drinks such as iced tea or a soft drink, with a slice either inside or on the rim of the glass. Only lemons, however, are used in the Italian liqueur Limoncello. A wedge of lemon is also often used to add flavor to water.
The average lemon contains approximately 3 tablespoons of juice. Lemons warmed to room temperature before squeezing (in a microwave or by leaving on a counter) increases the amount of juice that can be extracted. Storing lemons at room temperature for long periods makes them more vulnerable to mold. Lemon juice is typically squeezed onto fish dishes; the acidic juice neutralizes the taste of amines in fish by converting them to nonvolatile ammonium salts. In addition, lemon juice is widely used, along with other ingredients, when marinating meat before cooking: the acid provided by the juice partially hydrolyzes the tough collagen fibers in the meat (tenderizing the meat), though the juice does not have any antibiotic effects.
