SUGAR CANE PROCESSING
Traditionally, sugarcane processing requires two stages. Mills extract raw sugar from freshly harvested cane, and sometimes bleach it to make "mill white" sugar for local consumption. Refineries, often located nearer to consumers in North America, Europe, and Japan, then produce refined white sugar, which is 99 percent sucrose. These two stages are slowly merging. Increasing affluence in the sugar-producing tropics increased demand for refined sugar products, driving a trend toward combined milling and refining.
The mill washes, chops, and uses revolving knives to shred the cane. Shredded cane is repeatedly mixed with water and crushed between rollers; the collected juices (called garapa in Brazil) contain 10–15 percent sucrose, and the remaining fibrous solids, called bagasse, are burned for fuel. Bagasse makes a sugar mill more than energy self-sufficient; surplus bagasse goes in animal feed or in paper manufacture.
Sugar and the colonization of the Caribbean
With the European colonization of the Americas, the Caribbean became the world's largest source of sugar. These islands could supply sugarcane using slave labor and produce sugar at prices vastly lower than those of cane sugar imported from the East. Thus the economies of entire islands such as Guadaloupe and Barbados became based on sugar production. By 1750 the French colony known as Saint-Domingue (subsequently the independent country of Haiti) became the largest sugar producer in the world. Jamaica too became a major producer in the 18th century. Sugar plantations fueled a demand for manpower; between 1701 and 1810 ships brought nearly one million slaves to work in Jamaica and in Barbados.
During the eighteenth century, sugar became enormously popular. Britain, for example, consumed five times as much sugar in 1770 as in 1710. By 1750 sugar surpassed grain as "the most valuable commodity in European trade — it made up a fifth of all European imports and in the last decades of the century four-fifths of the sugar came from the British and French colonies in the West Indies." The sugar market went through a series of booms. The heightened demand and production of sugar came about to a large extent due to a great change in the eating habits of many Europeans. For example, they began consuming jams, candy, tea, coffee, cocoa, processed foods, and other sweet victuals in much greater numbers. Reacting to this increasing craze, the islands took advantage of the situation and set about producing still more sugar. In fact, they produced up to ninety percent of the sugar that the western Europeans consumed. Some islands proved more successful than others when it came to producing the product. And in Barbados and the British Leeward Islands sugar provided 93% and 97% respectively of exports.
Planters later began developing ways to boost production even more. For example, they began using more manure when growing their crops. They also developed more advanced mills and began using better types of sugarcane. In the eighteenth century "the French colonies were the most successful, especially Saint-Domingue, where better irrigation, water-power and machinery, together with concentration on newer types of sugar, increased profits." Despite these and other improvements, the price of sugar reached soaring heights, especially during events such as the revolt against the Dutch and the Napoleonic Wars. Sugar remained in high demand, and the islands' planters knew exactly how to take advantage of the situation.
As Europeans established sugar plantations on the larger Caribbean islands, prices fell, especially in Britain. By the eighteenth century all levels of society had become common consumers of the former luxury product. At first most sugar in Britain went into tea, but later confectionery and chocolates became extremely popular. Many Britons (especially children) also ate jams. Suppliers commonly sold sugar in the form of a sugarloaf and consumers required sugar nips, a pliers-like tool, to break off pieces.
Sugarcane quickly exhausts the soil in which it grows, and planters pressed larger islands with fresher soil into production in the nineteenth century as demand for sugar in Europe continued to increase: "average consumption in Britain rose from four pounds per head in 1700 to eighteen pounds in 1800, thirty-six pounds by 1850 and over one hundred pounds by the twentieth century." In the 19th century Cuba rose to become the richest land in the Caribbean (with sugar as its dominant crop) because it formed the only major island landmass free of mountainous terrain. Instead, nearly three-quarters of its land formed a rolling plain—ideal for planting crops. Cuba also prospered above other islands because Cubans used better methods when harvesting the sugar crops: they adopted modern milling methods such as watermills, enclosed furnaces, steam engines, and vacuum-pans. All these technologies increased productivity. Cuba also retained slavery longer than the most of the rest of the Caribbean islands.
Mechanization
Beginning in the late 18th century, the production of sugar became increasingly mechanized. The steam engine first powered a sugar mill in Jamaica in 1768, and soon after, steam replaced direct firing as the source of process heat.
In 1813 the British chemist Edward Charles Howard invented a method of refining sugar that involved boiling the cane juice not in an open kettle, but in a closed vessel heated by steam and held under partial vacuum. At reduced pressure, water boils at a lower temperature, and this development both saved fuel and reduced the amount of sugar lost through caramelization. Further gains in fuel-efficiency came from the multiple-effect evaporator, designed by the African-American engineer Norbert Rillieux (perhaps as early as the 1820s, although the first working model dates from 1845). This system consisted of a series of vacuum pans, each held at a lower pressure than the previous one. The vapors from each pan served to heat the next, with minimal heat wasted. Modern industries use multiple-effect evaporators for evaporating water.
The process of separating sugar from molasses also received mechanical attention: David Weston first applied the centrifuge to this task in Hawaii in 1852.
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