The seeds are sown, there is a rich harvest. What happens next? The beet is delivered to AGRANA's sugar factories for processing . The beet is cleaned and reduced to small pieces then the sugar is extracted from the cuttings. The resulting syrup is then thickened and crystallized. Finally, the sugar crystals are separated from the syrup in centrifuges. The finished sugar is automatically packed and sent on its way to the store and to your sugar bowl to become a part of the sweet moments in your life.
Do you wonder how big the smallest sugar factory in the world is? Only a few inches - just as much as a sugar beet. Bellow you will learn more about it.
The sugar beet (Beta Vulgaris Saccharifera) is a biennial plant belonging to the goosefoot family. The taproot, (so-called beet), which is used to produce sugar, forms during the growing phase in the first year. With a sugar concentration of 16 to 20%, the sugar beet offers the highest yield among sugar-producing plants (sugar beet and sugar cane). The water content is around 75%.
Leaves
With the aid of solar energy and the chlorophyll in its leaves, the sugar beet plant converts carbon dioxide from the air, water and minerals in the soil into sugar. This process is called photosynthesis. The sugar beet foliage is left on the fields during harvesting.
Head
The head of the sugar beet plant, (from where the leaves branch off), contains many non-sugar materials and therefore needs to be removed during harvesting.
Root
The sugar produced during photosynthesis is stored in the root of the sugar beet. The lighter areas are those in which the concentration of sugar is particularly high.
After harvesting, sugar beet is collected on site (external storage) or delivered directly to plants. On arrival at the factory, the beet is weighed and unloaded from mobile platforms. It then accumulates on rotating and adjustable conveyor belts where it awaits processing. If not stored properly the sugar content decreases. The optimum storage temperature is between -3 and 5 ° C.
After the first washing and intermediate storage the beet is removed for processing.
1. Slicing
Slicing machines cut the beets into strips known as cossets with an average sugar content of between 16 and 20%.
2. Raw Juice production
The sugar is extracted from the cossets using hot water (around 70 °C) in a diffuser with the cossets moving in the opposite direction to the water flow (counter-flow-principle) - in a process known as extraction. The raw juice or liquor obtained contains around 98% of the sugar in the sugar beet as well as organic and inorganic constituents (so-called non-sugars) from the beet.
3. Juice purification
The non-sugars in the raw Juice are bound and extracted using natural substances - lime (CaO) and carbonic acid gas (CO2) which are produced in the site's own lime kiln.
4. Filtration
The insoluble non-sugars and the lime are filtered off in filter units. The filtrate is known as thin juice and the filter residue as carbonation-lime. This is an important soil improver and fertilizer which is spread on the fields.
5. Thick juice production
The thin juice is evaporated in hour-long steaming process to produce thick juice. On-site power plants provide the considerable quantities of energy needed for sugar production. The steam produced in the high-pressure boilers is used in the turbogenerators to produce electricity. The waste steam from the turbines is used as process heat (cogeneration) in order to heat the evaporator station.
6. Crystallization
The thick juice is thickened further in the boiling-pans under vacuum. The crystallization process is triggered by adding (spiking) the thick juice with finely ground sugar. Further evaporation allows the crystals to grow to the desired size.
7. Centrifugal
The sugar crystals are separated from the syrup by centrifuging. The separated syrup is further subjected to two crystallization process.
8. Sugar
The pure, crystal-clear sugar looks white when subjected to white light. White sugar contains at least 99.7% sucrose. The remainder is in effect moisture.
9. Sugar drying
White sugar is dried in air stream, cooled and stored in silos. In its many forms and packaged in numerous different household and industrial volumes, sugar is an important nutritional and semi-luxury food stuff which then makes its way to the end consumer.
Watch what you leave behind
Almost 100% of all used raw materials are recycled!
Molasses
The syrup that is separated during the final crystallization step is known as molasses. The molasses contains the non-crystallized sugar (6-9% of the sugar content of the beet) as well as the soluble non-sugars from the sugar beet. Molasses is a valuable ingredient for the baking yeast and animal feed industry as well as for alcohol production.
Pellets
The cossets from the sugar juice are mechanically pressed and, upon addition of molasses, dried in a drying tunnel before being pelleted and sold as animal feed.
Sugar cane is obtained from sugar cane shoots called ‘sets’ that are ready for harvest after eleven to eighteen months. Each shoot can be harvested up to seven times before it has to be replaced. Harvesting is done either mechanically or by hand. The dried leaves, called ‘trash’, are often burned away first to make the subsequent processing easier.
The cultivated cane must be processed as soon as possible after being harvested in order to obtain the sugar and to prevent sugar being broken down by microorganisms. Raw cane sugar is thus produced in factories that are located close to the growing area. The sugar cane is cleaned and compressed, then sprayed with hot water to extract the juice. This juice is then filtered, concentrated using pressurized steam and then crystallized. Then it's passed through centrifuges to separate it from the remaining syrup.
At this stage, the sugar is partly clean and exists in a crystallized, microbiologically stable form. As a commodity it can now be stored and transported to refineries around world.
The most important stages in refining raw cane sugar are:
Evaporation and crystallization
