The sensation of taste includes five established basic tastes&colon; sweetness, sourness, saltiness, bitterness, and umami. Sourness is the taste that detects acidity. Sugars and alcohol enhance a wine's sweetness; acids (sourness) and bitter tannins counteract it. Traditionally, there have been four primary tastes&colon; sweetness, bitterness, sourness, and saltiness. Saltiness and sourness are perceived when alkali metal or hydrogen ions enter taste buds, respectively. They typically have a slight sweetness, along with a distinct sourness. The detection of saltiness and sourness enables the control of salt and acid balance. This condition will usually be some attribute such as sweetness, sourness, intensity of flavour, etc. This lactic acid adds sourness to the beer. It contributes to the sourness of unripe apples. It acquires its characteristic sourness through inoculation with lactobacillus bacteria. Additional sourness may be had from lemon, lime or vinegar. Kabosu juice is rich in sourness, with a unique fragrance. Likewise, cream is replaced by flour to generate thickness without inducing sourness. Other variations of the dish derive their sourness from native ingredients.