Hydrated lime is essential to the production of sugar from both sugar cane and sugar beets. It is also used to purify sugar derived from other sources, such as maple or sorghum.
Sugar cane and sugar beets are harvested and processed with water to form raw juice, which has low pH and contains dissolved impurities. Hydrated lime is added to the juice to raise the pH and to react with the impurities to form insoluble calcium organic compounds that can be removed. Excess lime is removed by carbonation or by the addition of phosphoric acid. This process may be repeated several times depending on the purity of final product required.