History and Technology of Sugar In Trinidad & Tobago

Saccharum officinarum

L. GRAMINEAE, POACEAE

Common name: sugar cane

Sugar cane is the source of sugar in all tropical and subtropical countries of the world. Estimates for 1966 and 1967 indicate world production of cane sugar was about 41 million tonnes.

Several species of Saccharum are found in Southeast Asia and neighbouring islands, and from these cultivated cane probably originated. The sweet juice and crystallised sugar were known in China and India some 2500 years ago. Sugar cane reached the Mediterranean countries in the 18thC, and reached the Americas in early colonial times.

The cane plant is a coarse growing member of the grass family with juice or sap high in sugar content. It is tender to cold, hence it is suitable to tropical countries where it may be planted at almost any time of the year since the plant does not have a rest period. This results in heavier yields of cane and sugar where it is planted in sub-tropical conditions. For example, yields of cane and sugar per acre in Trinidad, where the cane is grown for about 2 years before harvesting, are from 3 to 4 times yields in Louisiana and Florida for they have to cut the cane from one season's growth.

Sugar cane plants are propagated by planting sections of the stem. The mature stems may vary from 1.2-3.6m (4-12ft) or more in height, and in commercial varieties are from 2-5cm (¾-2in) in diameter. The stem has joints or nodes as in other grasses. These range from 10-25cm (4-10in) apart along the aboveground section of the stem. At each node a broad leaf rises which consists of a sheaf or base and the leaf blade. The sheaf is attached to the stem at the node and at that point entirely surrounds the stem with edges overlapping. The sheath from one node encircles the stem up to the next node above and may overlap the base of the leaf on the next higher node. The leaf blade is very long and narrow, varying in width from 25-76mm (1-3in) and up to 150cm (5ft) or more in length. Also, at each node along the stem is a bud, protected under the leaf sheath. When stem sections are planted by laying them horizontally and covering with soil a new stem grows from the bud, and roots grow from the base of the new stem. The stem branches below ground so several may rise as a clump from the growth of the bud at a node.

In planting cane fields, mature cane stalks are cut into sections and laid horizontally in furrows. In Tobago and Trinidad 2 or 3 nodes are commonly when they are laid. Usually only one node on a stem piece develops a new plant because of polarity along the stem piece.

Planting is in rows about 1.8m (6ft) apart to make possible cultivation and use of herbicides for early weed control. As plants become tall lower leaves along the stems are shaded and die. These ultimately drop off, so only leaves toward the top remain green and active. Between the nodes the stems have a hard, thin, outer tissue or rind and a softer centre. The high-sugar-containing juice is in this centre. More than one crop is harvested from a planting. After the first crop is removed two or more so-called stubble crops are obtained. These result from growth of new stalks from the bases of stalks cut near the ground level in harvesting.

Harvesting

Harvesting of cane in Trinidad and Tobago is not highly mechanised, much of the work is done by hand. Cane is mainly cut by hand, cutting them off at ground level and then trimming off the top the canes at a uniform length - and deposit them in rows. In some areas the leaves and trash are burned from the cane in the rows by use of flame thrower type machines after they are cropped to return the ash into the soil as a fertiliser. An alternate method is to burn the leaves from the standing cane, after which it is cut. In both cases the cane is taken directly to the mill. Delay between cutting and milling in should be as short as possible since delay results in loss of sugar content.

Sugar Planting

In planting cane fields, mature cane stalks are cut into sections and laid horizontally in furrows. In Tobago and Trinidad 2 or 3 nodes are commonly used when they are laid. Usually only one node on a stem piece develops a new plant because of polarity along the stem piece.

Planting is in rows about 1.8m (6ft) apart to make possible cultivation and use of herbicides for early weed control. As plants become tall lower leaves along the stems are shaded and die. These ultimately drop off, so only leaves toward the top remain green and active. Between the nodes the stems have a hard, thin, outer tissue or rind and a softer centre. The high-sugar-containing juice is in this centre. More than one crop is harvested from a planting. After the first crop is removed two or more so-called stubble crops are obtained. These result from growth of new stalks from the bases of stalks cut near the ground level in harvesting.

Sugar Manufacture

Sugar is obtained from the cane at mills located near centres of production. The cane first goes through a washer, then is cut into small pieces by revolving knives. These cut pieces may then be shredded or may move to crushers directly. The crushers consist of two large grooved rollers mounted horizontally, one above the other. The crushed, macerated cane then goes through three or more roller mills which consist of grooved rollers with heavy hydraulic pressure maintained on the upper roller. Water, equal to about 20 percent, is added before the mixture is passed through each set of rollers except the last one. Efficient mills extract at least 90 percent of the sugar in the cane. The cane residue, called 'bagasse', can be used as an animal feed.

The mixture of plant sap and water, with the sugar in solution, collected from the roller mills is slightly acid in reaction with a pH of 5 to 5.5. It is neutralised with lime, which precipitates some of the colloids and other nonsugars and also stops conversion of sucrose to reducing sugars. The limed juice is then heated to boiling, which results in further formation of precipitates that settle to the bottom of the tanks. These are drawn off and filtered to remove more juice. The nearly clear juice is continuously drawn off from the top of the tank and goes to the evaporators.

The evaporators are a set of three vacuum pans or ‘bodies’ arranged in series, with each successive pan maintained under higher vacuum. The juice enters the first pan at 16 to 180 Brix and leaves the third at 55 to 750 Brix. It then goes to high-vacuum boiling pans - about 56cm (25in) of mercury - there it is further concentrated to 900 Brix and contains sugar crystals. It then is centrifuged to remove most of the liquid or molasses. The remaining raw or brown sugar is then ready for final refining. Much of the exported sugar is raw sugar and is further refined here before being marketed.

The final refining steps include melting the brown or raw sugar, decolouring by passing through carbon filters, recrystallising in vacuum boiling pans, and drying by centrifuging. Roughly 45kg (100lb) hundred pounds of raw sugar produces about 43.5kg (96lb) of refined. A tonne of cane yields from less than 80kg (175lb) to more than 105kg (230lb) of raw sugar, depending on such factors as variety, maturity when harvested, promptness of milling, and incidence of diseases on the cane in the field. The molasses obtained in milling is used as an additive in livestock feed, in the manufacture of alcohol and alcoholic beverages and to some extent in foods. The fibrous plant residue from the roller mills may be used as fuel at the mill, made into paper or insulating board, or used as plant mulches or bedding for livestock.

Sugar Cane Syrup

Sugar cane for syrup is also grown. The culture is essentially the same as for sugar cane and some of the varieties are the same. The syrup is manufactured on a small scale.

For best yield and quality of syrup, harvest should be delayed until the cane is. Leaves are stripped from the standing cane either by cutting off or pulling off by hand. Stems are topped and cut near ground level. Delay of up to 30 days between cutting and making the syrup does not impair either yield or quality of the syrup.

In general, mills with three horizontal rollers turned by motors are used to extract the juice. From 22.5-27kg (50-60lb) of juice should be obtained from 45kg (100lb) of cane. Open-type, continuous flow evaporators are generally used to concentrate the juice. The cold juice enters the lower end of the evaporator which is heated by fire beneath or, in larger installations, by steam coils. When the juice is heated, proteins and some other nonsugar constituents coagulate, float on the surface, and are skimmed off at the upper end. In manufactured apparatus a final finishing or evaporating vat may be used. Proper density of the finished product is determined by using a hydrometer (35-360 Baume), or determining the boiling point with a thermometer 108-109°C (226-228°F.).

The finished syrup is then filtered and placed in containers while hot. Production of cane syrup has fluctuated widely reaching more than 106,000,000 liters (28,000,000 gallons) in 1945 when sugar was scarce because of World War II. Production in 1966 and 1967 averaged 8,142,000 litres (2,151,000 gallons) annually. All is used as food.

Mills

The mills used to produce sugar in the past were powered by water or wind power. The overshot or undershot water mills were more common than windmills. The overshot mills being more practical and powerful for the conditions in Tobago and Trinidad.

Since ancient times, man has harnessed the power of the wind to provide motive power for transportation.

Of course wind was not the first non-human power source applied to the task milling - it was preceded by both animal power. European millwrights became highly skilled craftsmen, developing the technology tremendously, and as Europeans set off colonising the rest of the globe, windmills spread throughout the world and into the Caribbean.

These remaining windmills, scattered throughout the Caribbean and in Trinidad and Tobago, are an historic reminder of a past technological age.

Architectural Features

Although the old plantation houses have seen better days it is still worth a visit! The rubble walls comprise of boulders held together with a mixture of egg-white and coral dust or cement.

The mill factories were driven by slave labour until 1807 when Britain abolished the slave trade. Sugar cane harvesting and processing was backbreaking work. The soil in the area was very thin and planting was done on hillsides. The hills had to be terraced and the soil fertilised with ash and dung with a plentiful supply of water.

The sugar cane had to be then planted and then harvested 12 to 18 months later. Once harvested the cane was brought to the windmill where it was crushed and the juice from it was collected. If there was no wind the cane was crushed on a slave or horse driven mill.

After the juice was collected it was then sent to the boiling bench. Roughly 1200-2000 litres (300-500gallons) of juice could be produced per hour this way The cane juice was boiled in ‘coppers’ which were heated copper pans - see illustration below. The coppers were heated by fires fuelled with dry cane stalks. Boiling caused excess water in the juice to evaporate out and impurities could be skimmed off of the top of the pan. The juice was progressively boiled and ladled into smaller and smaller coppers until it was poured off into wooden pans to cool and allow sugar crystals to form.

Finally, it was poured into conical moulds. The sugar 'loaf' thus derived its distinctive shape from this early method of obtaining white sugar. The molten sugar was poured into these cone-shaped moulds which were arranged point downwards. As it hardened into crystalline consistency, additional cleansing syrups were passed through - draining from a hole at the base of the mould. After a long period of drying, the now solid cone of sugar was removed from its mould, and sold in this form to grocers, or direct to wealthy customers, because sugar was still a luxury food.

If molasses was desired instead of sugar the juice was removed from the last copper early to prevent sugar crystal formation. The sugar was then placed into barrels called hogsheads which could hold up to 725kg (1600lb) of sugar. Drippings from the wet sugar were stored in hogsheads and were used to produce rum.

The History of Sugar Production

Sugar, and the demand for it, has been a major demographic force in world history. Because of it, millions of people entered the New World from Europe and Africa, particularly to South America and the Caribbean on to Tobago and Trinidad. Sugar also brought dozens of ethnic groups to the islands but mainly from Africa. Sugar from colonial plantations flowed to cities, while food, machinery, clothing and many other goods flowed back. The history of sugar consumption was shaped by cultural preferences, and various forms evolved to satisfy particular regional desires.

In the first centuries of European sugar consumption, cane sugar was not an undifferentiated commodity like refined white sugar today. Sugar was sold mostly both by the loaf and the pound, and ranged from dark reddish-brown to white in colour. Unrefined brown sugars were exported in chests and hence given the name ‘casson sugars.’ In the 1600s, ‘clayed’ and ‘muscovado’ sugars were introduced to England from Barbados. Commercial sugar refineries, supplied by New World production, appeared in England in the 16thC.

Until the late 1700's sugar was served by European nobility as a way to validate rank and social power. Sugar also had a special status as a medicine in early years. It was blended with other herbs and spices and used in preservation and decoration.

In the works of Arabic writers between 10thC and 14thC, sugar is an important medicinal ingredient. Islamic texts transmitted the medical lore of sugar to Muslim, Jewish and Christian physicians from Persia to Spain. By the thirteenth century, prescriptions of medical tonics containing sugar began to appear in Europe. It was blended with other herbs and spices and used in preservation and decoration. Thomas Aquinas wrote in the 12thC: ‘Though they are nutritious themselves, sugared spices are nonetheless not eaten with the end in mind of nourishment, but rather ease of digestion; accordingly, they do not break the fast any more than taking any other medicine.’ Of the ‘tropical commodities’ introduced to Europe, including tea, coffee, chocolate, tobacco and rum, only sugar escaped religious prescription.

By 1850, sugar had been transformed from a luxury to a commodity in English life. This was a partly a result of geography: in the north, fruits and vegetables were less common than in Mediterranean countries, and sugar helped take their place. The English also drank sweet ales, and so were already accustomed to a sweet taste. Sugar, particularly as a complement to tea, quickly became one of the first foods in the ‘work break’ of the industrial revolution.

The History of Sugar Consumption

Sugarcane was first domesticated in New Guinea about 10,000 years ago, and began its migration west to India and east to the Philippines. Trade routes from Asia eventually brought the sugarcane plant to Egypt around 3,000BC. The Egyptian nurtured remarkably adept chemists, and developed many of the sugar milling techniques, such as clarification and evaporation, that are still in use today.

The first written evidence of sugar making is in a Hindu religious document dated 500AD. The document details a method of boiling the cane juice to make molasses and crystalline balls of sugar. We know that the Arabs understood the art of extracting sugar from the sugar cane. They used mills to crush the cane, thereby squeezing the sugary juice from the fibre and, through different processes, ultimately obtaining crystallisation.

The enriched sugar was cast into conical moulds for filtration and was transported in the form of 'loaves'. The Arab expansion westward into Spain introduced sugar technology to Europe. Wherever they went, the Moors brought both the product and technology of sugar. The various grades of crystalline sugar produced by the Moors ranged widely in colour, molasses content, grain size and form, depending on the mill processes and regional preferences. The Ancient Greeks spoke of saccharum in panibus, sugar in loaves. It is considered that the introduction of cane sugar to Northern Europe was helped by the Crusaders bringing back, as a pleasant novelty, samples of the new sweet substance. From this period onwards, the trickle of sugar from East to West increased to a marketable flow, mainly through Venice.

Sugar was introduced to the New World by Christopher Columbus in 1493. It was brought from the Canary Islands and first grown in what is now the Dominican Republic. Sugar plantations began to develop in the early 1500s. By 1526, Brazil was shipping sugar to Lisbon in commercial quantities.

For a long time it was a luxury item found only on the tables of palaces and aristocratic mansions. The English court of Elizabeth I apparently had a predilection to sweeten almost everything they ate with sugar, perhaps because the Queen had a sweet tooth.

By the 16thC, Brazil - and the Portuguese - dominated world sugar production. Cuba grew to become a major centre for New World production in the 1700s, allowing Spain to challenge Portuguese control of the market. Over this period, production increases were driven by the geographic expansion of plantations, rather than yield increases from land or cane. Sugar production and consumption expanded dramatically in the seventeenth century, when British ‘sugar islands’ such as Jamaica, Barbados, Trinidad and Tobago made inroads into a sugar trade dominated by Cuban and Brazilian production. Sugarcane products multiplied, and included many crystalline varieties of sugar, syrups, rum and molasses. By 1675, 400 vessels with an average of 150 tonnes of sugar each were sailing to England annually. Sugar plantations became a synthesis of field and factory: sugarcane must be cut when it is ripe, and milled as soon as it is cut. This gave rise to plantations and mills dedicated to the production of sugar. Consumers in different cultures and historical periods developed preferences for purity, colour, form and grain size, necessitating skilled, artisans' knowledge of sugar milling.

By the late 1800s, after Cuba had surpassed Brazil to become the largest sugar producing country in the world, drastic forces began to re-shape the Caribbean sugar industry. Slavery ended in Puerto Rico and Cuba, and Haiti underwent a revolution. Throughout the region, emancipation meant a sharp decrease in sugar production. Britain's Navigation Acts began to establish free trade, so English plantations could no longer rely on nationalist market quotas. At the same time, beet sugar extraction began to make a serious dent in the world market. However, major technological improvements in grinding capacity, cane varieties, pest control and revolutionary changes in transportation greatly increased cane sugar efficiency.

In 1862, Dr. Alvaro Reynoso published Essay on the Growing of Sugar Cane. Reynoso, born in the province of Havana, Cuba, was educated at the Royal University of Havana and the University of Paris. The book revolutionised the sugar industry by introducing scientific yield-management methods, which greatly increased sugar yield per acre. It was translated into French, Dutch, English and Portuguese, and quickly spread throughout the Caribbean. Reynoso helped transform Cuba into a center of scientific agronomy. The book immortalised the native-born Reynoso, and today Cuba still celebrates ‘Sugar Cane Day’ on Reynoso's birthday.

From 1789 through 1934, the United States taxed sugar imports to raise revenue, and these import duties and excise taxes were a major source of revenue for the Treasury. Following the Spanish-American War in 1892, Cuba, Puerto Rico and the Philippines received protection in the USA sugar market. Production in Cuba and Puerto Rico expanded rapidly, and they became heavily dependent on USA sugar policy. After the advent of Communism in Cuba, USA policy denied Cuban sugar access to the American market. This, combined with an influx of knowledgeable and skilled Cuban refugees into Florida, marked the beginning of a significant expansion of the USA cane sugar industry.