A process for producing a stevia composition comprising rebaudioside B, comprising the steps of: providing a stevia sweetener, wherein the stevia sweetener comprises rebaudioside A; providing an alkaline aqueous solution; dispersing the stevia sweetener in the alkaline solution and incubating for 12 to 48 hours at 55-75°C to form a mixture; cooling the mixture to 10-30°C and adjusting the pH with acid to pH 3.0- 4.0; incubating the mixture at low temperature to obtain a precipitate; separating the precipitate and washing it with water; and drying the washed precipitate to obtain the stevia composition; the method further comprising the steps of: dispersing the stevia composition in water to form a mixture; adding a base into the mixture; incubating the mixture to facilitate at least partial conversion of carboxyl groups of the rebaudioside B into a carboxylate salt to make a rebaudioside B carboxylate salt; and separating and drying the stevia composition comprising the rebaudioside B carboxylate salt; the method comprising the further steps of: suspending the rebaudioside B carboxylate salt in water and incubating at an elevated temperature for 1-3 hours, wherein the elevated temperature is a temperature of 50 to 100°C; separating the rebaudioside B carboxylate salt from the water and drying the rebaudioside B carboxylate salt to obtain a purified rebaudioside B carboxylate salt; wherein the purified rebaudioside B carboxylate salt comprises rebaudioside B with greater than 99% purity. providing a stevia sweetener, wherein the stevia sweetener comprises rebaudioside A; providing an alkaline aqueous solution; dispersing the stevia sweetener in the alkaline solution and incubating for 12 to 48 hours at 55-75°C to form a mixture; cooling the mixture to 10-30°C and adjusting the pH with acid to pH 3.0- 4.0; incubating the mixture at low temperature to obtain a precipitate; separating the precipitate and washing it with water; and drying the washed precipitate to obtain the stevia composition; the method further comprising the steps of: dispersing the stevia composition in water to form a mixture; adding a base into the mixture; incubating the mixture to facilitate at least partial conversion of carboxyl groups of the rebaudioside B into a carboxylate salt to make a rebaudioside B carboxylate salt; and separating and drying the stevia composition comprising the rebaudioside B carboxylate salt; the method comprising the further steps of: suspending the rebaudioside B carboxylate salt in water and incubating at an elevated temperature for 1-3 hours, wherein the elevated temperature is a temperature of 50 to 100°C; separating the rebaudioside B carboxylate salt from the water and drying the rebaudioside B carboxylate salt to obtain a purified rebaudioside B carboxylate salt; wherein the purified rebaudioside B carboxylate salt comprises rebaudioside B with greater than 99% purity. dispersing the stevia composition in water to form a mixture; adding a base into the mixture; incubating the mixture to facilitate at least partial conversion of carboxyl groups of the rebaudioside B into a carboxylate salt to make a rebaudioside B carboxylate salt; and separating and drying the stevia composition comprising the rebaudioside B carboxylate salt; the method comprising the further steps of: suspending the rebaudioside B carboxylate salt in water and incubating at an elevated temperature for 1-3 hours, wherein the elevated temperature is a temperature of 50 to 100°C; separating the rebaudioside B carboxylate salt from the water and drying the rebaudioside B carboxylate salt to obtain a purified rebaudioside B carboxylate salt; wherein the purified rebaudioside B carboxylate salt comprises rebaudioside B with greater than 99% purity. suspending the rebaudioside B carboxylate salt in water and incubating at an elevated temperature for 1-3 hours, wherein the elevated temperature is a temperature of 50 to 100°C; separating the rebaudioside B carboxylate salt from the water and drying the rebaudioside B carboxylate salt to obtain a purified rebaudioside B carboxylate salt; wherein the purified rebaudioside B carboxylate salt comprises rebaudioside B with greater than 99% purity.