Sugar or sugar syrup extracted from sugar beet is highly suitable for the production of bioethanol. Unlike cereals, however, sugar beet cannot be stored for longer periods. In Europe, sugar beet processing takes place in the autumn in a campaign that lasts about 100 days. So-called thick juice ? an intermediate product in the manufacture of sugar ? can be stored for the whole year and is available in the sugar factory for the production of white sugar or as a raw material for the production of bioethanol.
For centuries people in Europe had to rely on honey, fruit sweetening or cane sugar for sweetening food and drink. In 1747, the chemist Andreas Markgraf discovered that the coveted luxury food and food additive could also be extracted from sugar beet.
Markgraf?s student Franz Carl Achard then created the foundations for the industrial production of sugar from beet and in 1802 opened the first beet sugar factory in Europe. Since about 1850, sugar has been produced in Europe from sugar beet on a large scale.
Botanically, sugar beet belongs to the goosefoot family (Chenopodiaceae). Its original form is believed to be the sea beet. The sugar beet is very demanding as to soil and climate, and thrives best on deep, rich soils with an ample supply of water. In Germany, sugar beet is harvested in the late autumn, with yields ranging from 50 to 90 tonnes per hectare.
The sugar content of the beet is in the region of 16-20%. The beet foliage is either used as animal feed, or may be left on the field as compost, while the beets are cut into chips in the sugar factory. These are then soaked in water and heated. The raw juice produced is purified and concentrated into thick juice. The thick juice, with a sugar content of around 63%, can be used to produce sugar or bioethanol. For the production of sugar the thick juice is boiled and separated from the syrup in centrifuges. For the production of bioethanol, the thick juice can be fermented directly with the aid of yeasts.
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