The sour taste is one of the five basic tastes, alongside sweet, salty, bitter, 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. Sourness can serve as a warning signal for spoilage, as many spoiled foods develop acidic properties. The perception of sour taste is influenced by factors such as concentration and temperature, making it a key component in balancing flavors in cooking and food preparation.