Samedi dernier, les étudiants des cours d’Anglais de Mme Virginie Malfait sont allés visiter la sucrerie de Fontenoy… en anglais.
Ils étaient accompagnés d’un guide professionnel ainsi que d’un ancien étudiant qui travaillait sur place et qui est guide, lui aussi, maintenant.
Vous trouverez, ci-dessous, quelques clichés souvenir de cette visite.
Et un petit résumé, en anglais dans le texte (of course!) sur la production de sucre à partir de betteraves.
How Beet Sugar is Made
A School Visit to Iscal/Fontenoy, Dec.16th 2017
Sugar beet is a temperate climate biennial root crop. It produces sugar during the first year of growth in order to see it over the winter and then flowers and seeds in the second year. It is therefore sown in spring and harvested in the first autumn/early winter. A typical sugar content for mature beets is 17% by weight but the value depends on the variety and it does vary from year to year and location to location.
The beets are harvested in the autumn and early winter by digging them out of the ground. They are usually transported to the factory by large trucks. Because the beets have come from the ground they are much dirtier than sugar cane and have to be thoroughly washed and separated from any remaining beet leaves, stones and other trash material before processing.
The processing starts by slicing the beets into thin chips. This process increases the surface area of the beet to make it easier to extract the sugar. The extraction takes place in a diffuser where the beet is kept in contact with hot water for about an hour. The diffuser is a large tank in which the beets slices slowly work their way from one end to the other and the water is moved in the opposite direction. As the water goes it becomes a stronger and stronger sugar solution usually called juice.
The exhausted beet slices from the diffuser are still very wet and the water in them still holds some useful sugar. They are therefore pressed in screw presses to squeeze as much juice as possible out of them. This juice is used as part of the water in the diffuser and the pressed beet, by now a pulp, is sent to drying plant where it is turned into pellets which form an important constituent of some animal feeds.
The juice must now be cleaned up before it can be used for sugar production. This is done by a process known as carbonatation where small clumps of chalk (lime stone) are grown in the juice. Once this is done the sugar liquor is ready for sugar production except that it is very dilute.
The next stage of the process is therefore to evaporate the juice in a multi-stage evaporator.
For this last stage, the syrup is placed into a very large pan, typically holding 60 tons or more of sugar syrup. In the pan even more water is boiled off until conditions are right for sugar crystals to grow. In the factory the workers usually have to add some sugar dust to initiate crystal formation. Once the crystals have grown the resulting mixture of crystals and mother liquor is spun in centrifuges to separate the two, rather like washing is spin dried. The crystals are then given a final dry with hot air before being packed and/or stored ready for despatch.
The final sugar is white and ready for use, whether in the kitchen or by an industrial user such as a soft drink manufacturer. As for raw sugar production, because one cannot get all the sugar out of the juice, there is a sweet by-product made: beet molasses. This is usually turned into a cattle food or is sent to a fermentation plant such as a distillery where alcohol is made.