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Sugarbeets

Chenopodiaceae Beta vulgaris L.

Source: Magness et al. 1971

Sugarbeets are the principal source of domestic sugar for the temperate areas of the world. World-wide production of sugarbeets was about 18.5 million acres (average for 1966-67) with 1,240,000 acres in the United States. Beet sugar production in the United States for the two years averaged 2,748,000 tons or a little over 2 tons of sugar per acre of beets grown.

Cultivated beets are believed to have been derived from B. vulgaris L., native to Mediterranean coastal areas of Europe. Though used much earlier as vegetable and feed crops, beets as a sugar source have been developed only during the past 170 years. In 1811, following knowledge that some kinds of beets were rich in sugar, Napoleon ordered extensive production of such beets and the construction of plants to extract the sugar in France. Although this was partially successful and provided some sugar during the Napoleonic wars, the industry passed out following his defeat at Waterloo and the opening of the country to imports of cane sugar from tropical areas. However, around the middle of that century a substantial industry developed in Germany and France based on higher sugar content beets and improved techniques of sugar extraction.

Although sporadic attempts to produce sugar from beets in the United States occurred from 1830 onward, the first successful mill was built in 1879 at Alvarado, California. A factory on the site operated until, 1968. Today sugarbeet growing and sugar manufacture are major industries from the Great Lakes west to the Pacific. Major production centers are irrigated lands of the Rocky Mountain States and westward, but substantial production also occurs in the North Central and Plains States, and limited quantities are produced in New York and Maine.

The beet plant is an overwintering biennial that produces a rosette of leaves and enlarged root one year and a fruiting stalk the followinc, season. Except for seed production, however, it is grown as an annual seeded in spring and harvested in the fall. The leaves during that year rise from the crown of the enlarged root. Largest leaves may reach 18 inches or more in over-all length. Half or more of that length is petiole and the rest the leaf blade. The blade is generally elongated oval to arrowshaped but irregular and somewhat roughened. Up to 75 leaves may rise on a vigorus plant. The first-formed leaves die after about a month, but leaves formed in midsummer persist until harvest. Roots are generally broadly conic in shape and average about 4 inches diameter at the top, and near twice as long. Under favorable growing conditions, roots of high sugar-content varieties may contain 20 percent sugar by fresh weight at harvest.

Beets are planted in rows 24 to 28 inches or more apart. After growth has started plants are thinned in the row to leave them 8 to 12 inches apart. Maximum yields are obtained with a long growing season so planting is done as early in spring as the soil can be worked. Harvest is usually as late as possible before the ground freezes. Harvesting in the United States is highly mechanized. Machines dig the plants, cut off the top of the root with adhering leaves, and deliver the roots into trucks. The leaves with crowns are used for livestock feed either directly or as ensilage. The roots are delivered to the sugar mills where they may be stored in piles before the mill can take them. In very large piles aeration of the beets may be necessary to prevent heating.

The process of extracting sugar is briefly as follows: Roots are thoroughly washed, then cut into thin strips termed cossettes or chips. Sugar is removed from these by diffusion with hot water through a series of compartments, the fresh hot water first reaching the cossettes from which most of the sugar has been removed and progressively passing on to cossettes containing more sugar. This hot water. moving counter to the sugar content of the cossettes, emerges as "raw juice" with a sugar content of 10 to 15 percent. This is treated with lime to precipitate nonsugars; then with CO2 gas and filtered - emerging as so-called "thin juice." This is run through a series of five steam-heated vacuum evaporators. The final super-saturated solution is "seeded" with sugar crystals to promote crystallization of the sugar. Crystals are removed by centrifuge. The separated molasses is reboiled and centrifuged to remove additional sugar. Finally the molasses is treated with lime and mixed with raw juice to extract still more sugar.

In addition to the beet tops (used directly as animal feed, or after drying or ensiring), the pulp (after sugar extraction) is excellent feed for cattle and sheep. It is commonly dried at the sugar mill but may be fed as wet pulp. The molasses may be added to the pulp for feed or may be sold separately for mixing with other feeds. It is also used in industry for fermentation.


Last update June 28, 1996 bha