Beet Sugar

The structural contrast with cane is worth stating plainly. A cane mill makes raw sugar and ships it to a refinery, often on another continent, because cane grows in the tropics and much of the demand is elsewhere. A beet factory does the whole job in one place: sliced beet in at one end, white sugar out at the other, in a single continuous operation during the campaign.

Beet grows in the same temperate regions that consume the sugar, so there is no long haul to justify an intermediate product, and beet juice purification is integral to the process rather than an added stage. That is why the primary product of the beet commodity is finished sugar itself, and why "raw beet sugar" — though it exists as a tariff category and is occasionally produced — is not the industry’s normal output.

Beet is washed, weighed, tared, and sliced into thin strips called cossettes. Sugar is then drawn out by diffusion — hot water flowing counter to the cossettes, so that sugar passes out of the cells into the water — rather than by the crushing that cane gets. This is a real difference, and it works because the beet cell will surrender its contents to hot water while the cane stalk must be torn apart.

The raw juice that emerges carries a substantial load of non-sugars and is purified before anything else can happen: lime is added and then carbon dioxide, forming a precipitate that adsorbs and carries out impurities, and the purified juice is filtered. It is then evaporated to a thick syrup and boiled under vacuum until sucrose crystallises. The crystals are spun off, washed, dried, and screened; the syrup they came from is recycled through further crystallisation stages until what is left is beet molasses.

White sugar is bought on purity, colour, and grain. Colour is expressed in ICUMSA units — an internationally used scale where a lower number means a whiter sugar — and the value required is set by the buyer and the contract, since a soft drink maker and a bulk industrial user are not asking for the same thing. Grain size, moisture, ash, and freedom from any foreign matter complete the specification. Beyond a certain point these are cleanliness measures, and cleanliness is essentially what a refined sugar is.

Sugar is hygroscopic and it cakes. Silo storage of white sugar therefore involves conditioning the crystal before it goes in and controlling the atmosphere around it, because a silo of caked sugar is a serious problem to recover. It ships in bags, big bags, and bulk, and — as with any fine dry organic solid handled in quantity — sugar dust is an explosion hazard that handling systems are designed around.

A beet factory sells three things, not one. The exhausted cossettes leave diffusion as beet pulp, pressed and usually dried and pelleted for the feed market. The final liquor leaves crystallisation as beet molasses, carrying the sucrose that the beet’s own impurities refused to release. Both have real markets and are planned for, which is why this reference treats them as co-products rather than residues.

The relationship between the three is direct. The melassigenic impurities the factory pays attention to at beet intake are the ones that will divert sucrose into the molasses stream instead of into the sugar; the quality of the beet delivered therefore determines, before processing even begins, how the outputs will divide between them.