Refined White Sugar from Raw Cane Sugar

Raw cane sugar is sucrose crystals with a sticky brown coating of molasses. Refining removes that coating and the colour to give white sugar. The crystals are first softened in a concentrated syrup (affination), then dissolved. The syrup is cleaned by carbonatation: milk of lime and carbon dioxide form calcium carbonate, which settles out and carries impurities with it. Colour is taken out with granular activated carbon. The syrup is then boiled down, cooled and seeded so the sugar crystallises, the liquor is spun off in a centrifuge, and the white crystals are dried in hot air. The left-over liquor becomes refiners' molasses. Refined sugar measures below 300 ICUMSA colour units; raw sugar is over 1,500.