This paper describes the effect of calcium hydroxide adding to cossettes on the purity quotient of sugar beet juice. The calcium hydroxide added before denaturation (0.03% Ca(OH)₂ on cossettes mass) improved the purity quotient about 0.5 in comparison with the purity quotient of juice from undenaturated cossettes. In the event of the cossettes denaturated without Ca(OH)₂ this difference was large too and it was about 3.0 units.