Sugar cane - early technology

Extracting sugar

Buddhist writings referred to the crushing of sugarcane in a yantra or machine. This machine would have been a forerunner of the kolhu. This is a system of mortar and pestle usually operated by bullocks and oxen, which is the traditional device used to extract oils and juices. References to a mortar and pestle to extract soma juice from plants occurs in the Rig Veda 3500 years ago. The kolhu is still used in the sugarcane growing regions of India to manufacture gur.

After the juice was pressed from the cane stalks in the kolhu, it was boiled down into a series of products. Sanskrit literature mentions phanita (thickened juice), then solid guda (jaggery), sharkara ( brown sugar or guda crystals drained of molasses but still unrefined), matsyandika (literally 'fish eggs' perhaps a type of crystallized sugar) and khand (sugar in the form of crystalline lumps).

In 326 BC, the Greeks described 'stones the colour of frankincense, sweeter than figs or honey'. They were referring to crystallised sugar lumps called khand (now khandsari).

By 700 AD the Persians had added innovations to the process. The stems were shredded and crushed in ox-driven machinery. The expressed juice was concentrated by boiling in shallow pans. Lime was added to make proteins in the juice coagulate, and bring other impurities to the surface which were skimmed off. Further boiling removed more liquid so that the sugar began to crystallize.

White sugar

White sugar was achieved in some areas in this early period by boiling the raw sugar with lime water and bull's blood. The coagulating blood drew more impurities and removed much of the brown colour. It was skimmed, then the liquid filtered, boiled again to concentrate it, then poured into moulds to solidify. They were broken up, redissolved and purified, now with egg-white. After this long process, the sugar was white enough and pure enough to be formed into loaves and traded.

In ancient India, although lime was used in the refinement process it is doubtful that ox-blood would have been part of it. The early technolgy of crystallization and solidification is not fully known. Fine cloths and water distilled through aquatic weeds were used as part of the process of gentle washing to create layers of crystals forming khand. Repeated redissolution, recrystallisation and washings served to whiten the crystals, then called misri.