Sourness is one of the five basic tastes, alongside sweetness, bitterness, saltiness, and umami. It is primarily detected by taste buds on the tongue, which respond to acids found in various foods. Common sources of sourness include citrus fruits like lemons and limes, as well as fermented products like yogurt and sauerkraut. The sensation of sourness can indicate the presence of spoilage in food, as many spoiled items become acidic. In cooking, sour flavors can enhance dishes, balancing sweetness and adding complexity. Sourness is also a key component in many cuisines, contributing to the overall flavor profile of meals.