| In the factory |
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In the sugar factory, the sugar beets are washed and shredded into strips called cossettes. Hot water is used to extract the sugar from the cossettes in a diffusion tower. This results in the so-called raw juice, which contains various organic and inorganic constituents of sugar beet, as well as the sugar. These constituents interfere with the later crystallisation of the sugar and therefore have to be removed in a further production process, juice purification. The extracted cossettes are pressed and dried and are later used as animal fodder. |
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The juice is purified using lime and carbon dioxide. This removes approx. 30 ö 35% of the non-sugar substances from the juice. The process produces carbonated lime with valuable ingredients, which is used as an acidity-regulator on the beet farms to keep the soil healthy. |
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The purification process results in a clear, thin, light yellow juice, which contains approx. 15% sugar. This thin juice is subsequently thickened by evaporating water from it in a series of several vessels, yielding a thick juice with a sugar content of 65 - 70%. |
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In crystallisers in the sugar end, more water is removed from the thickened juice at a reduced pressure. When a certain sugar concentration has been reached, fine crystals called seed crystals are added. Removing more water causes the seed crystals to grow to the desired size. The crystallisation process is then terminated. The heated mixture, termed a massecuite, is now a combination of approx. 50% sugar crystals and a thick syrup. |
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The massecuite is released from the heating pans into horizontal receiving tanks, in which the sugar crystals continue to grow during constant cooling. From this crystallisation mash stage, the massecuite finally enters the centrifugals. Here, at between 1,000 and 1,400 revolutions per minute, the crystals are separated from the syrup. A short jet of water washes the surface of the crystals, and the white sugar is emptied from the centrifugal drum. |
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After the initial crystallisation process, crystallisation is once more induced in the syrup which still contains sugar. Yellow-brown raw sugar is obtained from this process. Crystallisation is then induced on the spun-off syrup for a second time, resulting in an after-product raw sugar. The raw sugar and after-product raw sugar are dissolved, filtered and crystallised again, producing high-grade refined sugar ö shiny white sugar of the highest quality. The snow-white colour of sugar is achieved not by “bleaching”, as is often falsely claimed, but as the result of a careful purification process. |
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The syrup remaining after the final crystallisation process is called molasses. Despite its high sugar content of approx. 50%, conventional crystallisation techniques are unable to extract any more sugar from it. Molasses is used mainly in the production of yeast and alcohol. High-quality animal feed can be obtained by mixing molasses with extracted and dried cossettes. Molasses is also used to produce lactic acid for the pharmaceutical industry, as well as citric acid and glutamic acid used in food manufacture. |
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