From Wikipedia

Big Sugar

Part One/Two

Because of the need for labor-intensive processing to turn sugarcane into end-products, much of the history of the sugar industry has had associations with large-scale slavery.

Originally, people chewed sugarcane raw to extract its sweetness. Indians discovered how to crystallize sugar during the Gupta dynasty, around 350 AD. Sugarcane was originally from tropical South Asia and Southeast Asia. Different species likely originated in different locations with S. barberi originating in India and S. edule and S. officinarum coming from New Guinea.

However, sugar remained relatively unimportant until the Indians discovered methods of turning sugarcane juice into granulated crystals that were easier to store and to transport. Crystallized sugar was discovered by the time of the Imperial Guptas. Indian sailors, consumers of clarified butter and sugar, carried sugar by various trade routes. Traveling Buddhist monks brought sugar crystalization methods to China. During the reign of Harsha (r. 606–647) in North India, Indian envoys in Tang China taught sugarcane cultivation methods after Emperor Taizong of Tang (r. 626–649) made his interest in sugar known, and China soon established its first sugarcane cultivation in the seventh century. Chinese documents confirm at least two missions to India, initiated in 647 AD, for obtaining technology for sugar-refining. In South Asia, the Middle East and China, sugar became a staple of cooking and desserts.

Early refining methods involved grinding or pounding the cane in order to extract the juice, and then boiling down the juice or drying it in the sun to yield sugary solids that looked like gravel. The Sanskrit word for "sugar" (sharkara) also means "gravel" or "sand". Similarly, the Chinese use the term "gravel sugar" (Traditional Chinese: 砂糖) for what the West knows as "table sugar".