A shelf-stable liquid base composition useful for preparing acidified milk based beverages, e.g. by dilution with water in a beverage dispensing machine, comprises: from about 2 to about 10 weight % of denatured milk proteins expressed as solid-not-fat (SNF) milk components; from about 15 to about 80 weight %, expressed as sugar equivalents, of a carbohydrate based or non carbohydrate based sweetener; from about 0.35 to about 1.50 weight % of a carbohydrate based stabilizer; and an acidifying agent present in amounts necessary for achieving a pH of about 3.0 to about 3.8 of the said base composition. Methods for preparing such a base composition and acidified milk based beverages prepared by means of such a base composition.