Liming, carbonation and filtration
The extraction fluid contains not only sugar, but also a lot of impurities. That’s why we use lime and carbon dioxide to purify:
The slaked lime (Ca(OH)2) precipitates the impurities
The carbon dioxide (CO2) binds with the chalk to create calcium carbonate, which fixes the impurities and deposits them.
The calcium carbonate and the impurities are filtered. The result? A transparent fluid that contains 12 à 13% of sugar.