Sugarcane

• 1. Introduction

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  Sugarcane is a tall, perennial grass whose jointed stalks store sucrose, and in 2020 it became the world's largest crop by production quantity at 1.9 billion tonnes. A single skilled worker, swinging a cane knife or machete, can cut 500 kilograms of it in an hour. Around four-fifths of the sugar people eat begins inside these stalks, the rest coming mostly from sugar beets. The plant grows 2 to 7 meters tall, and a mature stalk is roughly three-quarters water, fiber, and sweetness in delicate balance. How did a wild grass from a single island reshape diets, drive forced migrations of millions, and end up powering cars? Why did a crop that yields honey without bees, in the old phrase, also become tied to slavery, debt bondage, and a deadly kidney disease? The answers run from New Guinea gardens to vacuum-boiled refineries, and from chewed raw stalks to Brazilian fuel tanks.

• 2. Out Of New Guinea

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  New Guinea is where Saccharum officinarum was first domesticated, on the island and the lands east of the Wallace Line, the modern center of the plant's diversity. Beginning around 6,000 years before present, growers selectively bred several strains from a wild ancestor, Saccharum robustum. Papuans and Austronesians did not first prize it as a human sweetener. They primarily used sugarcane as food for domesticated pigs.

  A second, separate domestication unfolded in Taiwan and southern China, where Austronesian peoples raised Saccharum sinense as a primary cultigen. The word for the plant is reconstructed as təbuS or CebuS in Proto-Austronesian, becoming tebuh in Proto-Malayo-Polynesian. It ranked among the original major crops of the Austronesian peoples from at least 5,500 years before present.

  Austronesian voyagers carried Saccharum officinarum eastward into Polynesia and Micronesia as a canoe plant by around 3,500 years before present. By around 3,000 years before present, traders moved it westward and northward to China and India, where it hybridized with S. sinense and S. barberi. The sweeter S. officinarum may have gradually replaced the older cultigen across maritime Southeast Asia, setting the stage for its journey into western Eurasia.

• 3. Honey Without Bees

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  Strabo recorded that the Persians and Greeks found reeds in India that yield honey without bees, a discovery placed between the sixth and fourth centuries BC. The earliest known production of crystalline sugar began in northern India, with the first evidence preserved in ancient Sanskrit and Pali texts. The first chemically refined sugar appeared in India about 2,500 years ago.

  Muslim and Arab traders carried sugar from medieval India around the eighth century into the Mediterranean, Mesopotamia, Egypt, North Africa, and Andalusia, all parts of the Abbasid Caliphate. By the 10th century, sources claim every village in Mesopotamia grew sugarcane. Refining technique spread east toward China and west toward Persia, reaching the Mediterranean in the 13th century, where Cyprus and Sicily became important production centers.

  The word itself traces this trade. Sugar descends ultimately from the Sanskrit śárkarā, which became sukkar in Arabic, saccharum or succarum in Latin, zucchero in Italian, and finally sucre in both Middle French and Middle English. The second word, cane, was added later, as the crop took root on Caribbean plantations. By the eighth century, sugar was a luxurious and expensive spice from India, and a 12th-century work, Ibn al-'Awwam's Book on Agriculture, even includes an article on growing it in Spain.

• 4. The Triangle Trade

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  Christopher Columbus brought sugarcane to the Caribbean during his second voyage, landing it first on Hispaniola, the island shared today by Haiti and the Dominican Republic. The first sugar harvest there came in 1501, and by the 1520s many mills stood in Cuba and Jamaica. The Portuguese carried the crop to Brazil, where by 1540 there were 800 cane sugar mills on Santa Catarina Island and another 2,000 on the north coast, Demarara, and Suriname.

  Sugar formed one corner of the triangle trade. Often shipped as molasses, it traveled from the Caribbean to Europe or New England to be made into rum. Profits bought manufactured goods, which went to West Africa and were bartered for enslaved people, who were carried back to the Caribbean and sold to sugar planters. Toil in the sugar plantations became a main basis for the Atlantic slave trade, supplying people to work under brutal coercion.

  The 1833 Slavery Abolition Act ended slavery through most of the British Empire, and many of the emancipated no longer chose plantation work. West Indian planters turned to cheap labour in China and India under indenture, a contract binding workers to unfree labour for a fixed term. The first ships carrying indentured labourers from India left in 1836. These migrations settled ethnic Indians, Southeast Asians, and Chinese people across the world, who in some islands now make up between 10 and 50 percent of the population.

• 5. The Human Cost

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  At least 20,000 people are estimated to have died of chronic kidney disease in Central America over the past two decades, most of them sugarcane workers along the Pacific coast. The condition is called Mesoamerican nephropathy, and it may stem from long hours in the heat without enough fluid. The same workers face high temperatures, harmful pesticides, and venomous animals while cutting cane by hand, the repetitive motion alone causing physical harm.

  In India, and especially in Maharashtra, an exploitative advance payment system ties production to forced labour. Workers fall deeply into debt, returning year after year while earning less than 5 dollars a day. They migrate for the harvest and live in makeshift tents in the fields, without toilets, electricity, or running water. Child labour is common, and child marriage between harvesters is frequent, even though both are illegal.

  Women who harvest cane face an unusually high rate of hysterectomies, with roughly 1 in 5 pressured to undergo the surgery by producers amid a lack of sanitary facilities, family planning, and medical leave. India is the world's second-largest sugar producer, and Maharashtra supplies one-third of the country's sugar before it enters a global supply chain that makes its origin hard to track. The Coca-Cola Company and PepsiCo have bought large amounts of Maharashtra sugar since at least the 2010s, mostly for Indian soft drinks, while denying any complicity in the abuses.

  Australia's own history echoes this pattern. Between 1863 and 1900, merchants and plantation owners in Queensland and New South Wales brought between 55,000 and 62,500 people from the South Pacific islands to work the cane. An estimated one-third were coerced or kidnapped into slavery, a practice known as blackbirding, while many others earned very low wages. Between 1904 and 1908, most of the 10,000 remaining workers were deported to keep Australia racially homogeneous.

• 6. Growing The Cane

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  Sugarcane is one of the most efficient photosynthesizers in the plant kingdom, a C4 plant that converts up to 1 percent of incident solar energy into biomass. In primary growing regions it can produce over 15 kilograms of cane per square meter, demanding a tropical or subtropical climate with at least 60 centimeters of annual moisture. It does not tolerate severe frosts, so most of the world's crop grows between 22 degrees north and 22 degrees south, with some stretching to 33 degrees in each direction.

  The plant grows on a remarkable range of soils, from fertile mollisols and heavy cracking vertisols to infertile acid oxisols, peaty histosols, and rocky andisols. Desert countries with good irrigation, such as Egypt, rank among the highest-yielding regions thanks to abundant sunshine and water. Sugarcane consumes 9 percent of the world's potash fertilizer production, and near the equator in Colombia, Ecuador, and Peru it climbs to altitudes of 1,600 meters.

  Modern stem cutting has overtaken seeds as the usual way to reproduce the plant. Each cutting needs at least one bud, and in advanced agricultural countries like the United States and Australia, machines plant chopped stalk sections called billets. After planting, a stand can be harvested several times, sending up new stalks called ratoons, though successive harvests yield less. North American growers replant after two or three harvests, while on the French island of Réunion cane is often harvested up to 10 years before replanting.

  Hand harvesting still accounts for more than half of production and dominates the developing world. The field is first set on fire, burning dry leaves and driving off venomous snakes without harming stalks or roots, before harvesters cut the cane just above ground level. Mechanical harvesters such as the Austoft 7000 series, the original modern design, cut at the base, strip the leaves, chop the cane into lengths, and blow the trash back as mulch. One machine can harvest 100 long tons an hour, but cut cane must be processed quickly because it begins to lose its sugar at once.

• 7. From Stalk To Crystal

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  Sugar crystals appear naturally white during crystallization, a fact that surprises many who assume color must be bleached out. Processing traditionally runs in two stages. Mills extract raw sugar from freshly cut cane, sometimes producing mill-white sugar for local use, with sulfur dioxide added to inhibit color-forming molecules and stabilize the juices during evaporation. Refineries, often nearer consumers in North America, Europe, and Japan, then turn out refined white sugar that is 99 percent sucrose.

  Milling yields more than sweetness. Bagasse, the residual dry fiber left after the juice is pressed out, serves as fuel for boilers and kilns, as raw material for paper and panelboard, as agricultural mulch, and as feedstock for chemicals. Molasses comes in two forms, strong-flavored blackstrap and a purer syrup, the first used in animal feed and to make ethanol, rum, and citric acid. Dried filter cake becomes animal feed, fertilizer, and a source of sugarcane wax.

  Refining purifies raw sugar through a sequence of careful steps. It begins with affination, mixing the sugar with heavy syrup and centrifuging to wash away the crystals' less pure outer coating. The syrup is then clarified by adding phosphoric acid and calcium hydroxide, which precipitate calcium phosphate that traps impurities and floats to be skimmed off. After filtering through activated carbon to remove color, the syrup is boiled to supersaturation and crystallized in a vacuum, even the final molasses still holding 30 to 35 percent sucrose.

• 8. Fuel In The Tank

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  In Brazil, gasoline is required to contain at least 22 percent bioethanol, drawn from the country's vast sugarcane crop. Ethanol comes as a byproduct of sugar production and may one day become the primary product rather than sugar itself. Making it from sugarcane is more energy efficient than from corn, sugar beets, or vegetable oils, especially when bagasse fuels the process, and well-to-wheels CO2 emissions can run 90 percent lower than conventional gasoline.

  The numbers behind Brazilian ethanol are striking. About 75 tonnes of raw sugarcane are produced per hectare each year, and the cane delivered to the plant, called burned and cropped, makes up 77 percent of the raw mass after stalks are separated from leaves and roots. Each tonne of this material yields 740 kilograms of juice and 260 kilograms of moist bagasse, and one hectare ultimately produces 4,000 litres of ethanol a year without any extra energy input, because the bagasse alone exceeds what distillation requires.

  Bagasse also powers the grid. Mauritius produces over 100 kilowatt-hours of electricity per tonne of bagasse, and with a world harvest above one billion tonnes of cane, the global energy potential from bagasse tops 100,000 gigawatt-hours. Newer cogeneration plants aim for 200 to over 300 kilowatt-hours per tonne. One report suggests bagasse could meet 20 percent of Brazil's energy consumption, and a greener path still is converting it into biogas using enzymes, a technology that could yet reshape how every cane field earns its keep.