About sugarcane
Where does sugar come from - ask a farmer
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What sugar is made from?
Sugar is made from the juice of a tropical grass called sugarcane.
Sugarcane itself looks like bamboo stalks and it is in the stalks that the plant stores energy that it doesn’t need straight away – rather like animals make fat. People like sugar for its sweetness and the energy it provides, so farmers grow these plants commercially to extract the sugar.
Most of Australia’s sugarcane is grown along the coast of Queensland, and the rest is grown in northern New South Wales and the Ord region in Western Australia.
How sugar is grown?
Sugarcane needs strong sunlight, fertile soil and lots of water (at least 1.5 metres of rain each year or access to irrigation) to grow.
Sugar is made in the leaves of the sugarcane plant by a natural process called photosynthesis and is stored as sweet juice in its stalks.
Planting
Sugarcane is grown by replanting part of a mature cane stalk. Farmers cut some of the fully grown cane stalks into lengths of about 40 centimeters called “setts”. The setts are planted by special machines, which drop them into furrows, add fertiliser and cover them with soil.
Growing
After a few weeks new shoots grow from buds on the joints of the setts and break through the surface of the soil. Up to 12 stalks grow from each sett, forming what is known as the stool of sugarcane.
A crop of cane takes about 9-16 months to grow. It is harvested during the drier months of the season – between June and December each year. When ripe, the cane is usually about 2-4 metres high.
Sugarcane growers look after the environment
Many growers are improving their farming practices to help reduce soil erosion and protect nearby waterways and the Great Barrier Reef.
Green cane trash blanketing is one way of protecting the environment, and has been implemented by about 75% of Queensland cane growers.
When growers adopt this method, they harvest the cane green and spread the trash cutting over the harvested paddock. These cuttings act as a protective blanket for the soil, preventing soil erosion, assisting in weed control, improving soil structure and conserving moisture in the soil. This reduces the need for soil cultivation which helps minimise soil erosion.
Farm Management System (FMS)
The sugar industry is introducing a new system called SUGARCANE FMS to help growers review and improve whole-farm performance. It will incorporate many of the things that growers are already doing into one manageable system. The aim of the FMS is to:
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Encourage grower adoption of good farming practices (sustainable and profitable).
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Demonstrate to the public that cane is grown in an environmentally friendly way.
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Show government that the cane industry is able to self-manage resources responsibly without the imposition of more regulation.
Harvesting
All sugarcane in Australia is harvested mechanically, the majority being cut green or unburnt.
Originally thousands of hand cutters harvested the crop. Although experimental machines began cutting cane as early as the 1920s, the industry depended heavily on manual cutters until well into the mid-1960s.
Tentative moves towards mechanisation accelerated after World War II as capable hand cutters became increasingly difficult to obtain for the expanding harvest.
Wholestalk machines were being used by 1944 but initially they did not have a major impact on the harvesting process. Mechanisation was given a strong boost by the advent of mechanical loaders. By 1957 around 30% of the crop was being loaded by machines and by 1962 they accounted for 65%.
From 1956 onwards ‘chopped cane’ harvesters began to take over from wholestalk machines. These machines were able to load as well as cut cane and by 1965 they were well established. By 1975 around 98% of the crop was cut by ‘choppers’. In 1979 Australia became the first sugar producing nation to convert entirely to mechanical cane harvesting.
Until the 1940s most cane was cut green by hand cutters with residual trash burnt on the ground. Burning became standard practice due to outbreaks of the potentially fatal Weil’s disease, labour shortages and the ability of manual cutters to cut and load burnt cane faster than unburnt cane.
Pre-harvest burning was standard practice until the early 1980s when some growers began to experiment with green cane harvesting and associated trash blanketing. The agronomic benefits of trash blanketing, combined with greater harvesting flexibility in wet weather, prompted the development of new technology. By 1998 around two thirds of the total crop was cut green and some northern areas were using this method almost exclusively.
In recent times the industry has been striving to improve the efficiency and productivity of its cane harvesting and transport practices. Particular goals are to improve cane and sugar yields through better harvest scheduling and by reducing cane and juice losses as cane passes through the harvester.
Fewer machines now cut larger tonnages, continuous crushing is being used in most areas and cutting outside of usual daytime hours has been adopted.
Cane harvesting usually begins in June and ends mid-December depending on the weather.
Typically, a cropping cycle comprises one plant crop and 3-4 ratoon (regrowth) crops.
Sugarcane grows for 9-16 months before being harvested but in cooler parts of New South Wales it is allowed to grow 18-24 months.
Transport
Once sugarcane has been harvested it must be transported to a sugar mill as soon as possible, but within 16 hours of being cut, to minimise deterioration.
The Australian sugar industry ensures prompt delivery of cane to mills by operating sophisticated rail and road transport systems.
The cane transport system usually involves infield transporters delivering cane from the harvester to mill bins placed at local sidings. The industry maintains a dedicated network of nearly 4000 km of narrow-gauge rail lines. Some mills use a combination of rail and road transport but six operate road transport only.
Computerised cane transport scheduling systems enable cane movements to be continually monitored. When the cane arrives at a mill it is weighed and processed at automatic cane-receiving stations. The weight of cane in each bin and the name of the producing farm are automatically recorded. The billets (short pieces of canestalk) are tipped onto a cane carrier for transport to a shredder, which chops and shreds the cane into fibrous material and ruptures the juice cells. Pairs of rollers feed the cane through a series of mills comprising three large rollers arranged in a triangular formation. This separates the juice from the fibrous material, which is called bagasse. The juice is pumped away for processing into raw sugar and the bagasse is used as fuel in the mill’s boiler furnaces.
Since 1964 all raw sugar in Australia has been handled and transported in bulk. Queensland bulk sugar terminals are located at Cairns, Mourilyan, Lucinda, Townsville, Mackay, Bundaberg and Brisbane. Sugar produced at mills is transported to the local port terminal by road, mill-owned rail system or Queensland Government railway.
Sugar Milling
Cane must be delivered to the mill as soon as possible after harvesting (no later than 16 hours), to avoid deterioration in its sugar content.
Australia has 28 mills. An extensive transport system has been developed which allows harvested cane to move quickly and efficiently to sugar mills by road or rail. Sugar mills own over 4000 kilometers of narrow gauge tramway to help prompt sugar delivery.
At the mills, the sugarcane is crushed by large rollers. The extracted juice is then cleaned to remove impurities. The juice is thickened into a syrup by boiling off the excess water, seeded with raw sugar crystals in a vacuum pan and boiled until sugar crystals have formed and grown. The crystals are then tumble-dried and placed in large storage bins for transport to bulk sugar terminals before being sent to refineries.
Sugar mills are large, self-contained factories which only operate during the harvesting and crushing season, which in Queensland is between July and December.
All by-products from Queensland mills are recycled, adding to the efficiency of the milling process.
Bagasse, the cane fibre remaining after the juice has been extracted provides much of the fuel needed to power the mills, so the mills are effectively solar powered.
Other by-products such as ash (boiler ash is “scrubbed” from the mill stacks) and filter mud (the residue left after the sugar has been cleaned) can be used as a fertiliser on cane farms and gardens.
Molasses is the dark syrup separated from raw sugar crystals during the milling process. It is used as a raw material for ethanol and rum. It can also be used for animal feed.
Milling
Australia has among the most efficient and technologically advanced sugar mills in the world. They are located within the areas where sugarcane is grown.
Since 1988 four factories have closed and two innovative, automated plants have opened (one in Western Australia and a juice factory on the Atherton Tablelands in North Queensland). Most sugar mills were established more than a century ago and the WA factory was the first new mill in Australia in 70 years.
Since 1988 mills have become larger and ownership has consolidated. Seven mills are owned by CSR Ltd, six by Bundaberg Sugar Ltd, four by Mackay Sugar Co-operative Assn Ltd, three by the NSW Sugar Milling Cooperative, five other single mills by grower cooperatives, one by a public company, one by a private company and one by an overseas company.
During that time, the average mill crushed around 900 000 tonnes and the largest processed 2.1 million tonnes. By 2005 the average was 1.4 Mt and our largest mill was crushing 3.1 Mt. Three mills were crushing more than two million tonnes in a 22-25 week season with a single milling train.
The growing and milling sectors are closely interdependent due to the perishability of sugarcane and transport costs. Sugarcane is delivered to mills by rail and/or road transport systems designed to minimise delays between cutting and crushing so as to ensure good quality cane for the milling process.
Sugar mills crush and wash the juice from cane stalks and separate as much sucrose as possible from the water, impurities, fibre and dirt that comprise the rest of the cane juice.
Modern technology used by Australian sugar mills includes computer-based control and management systems, NIR (near infra red) reflectance spectroscopy, dry cane cleaning, improved clarification procedures, continuous pan boiling processes, and improvements in bagasse combustion technology.
Australia has an international reputation as a reliable producer of high quality sugar. All Australian sugar is stored and transported in bulk.
A number of sugar mills have established electricity co-generation plants.
By products from the cane crushing/refining process include bagasse (the fibre remaining after the cane is crushed), mill mud, ash, molasses, ethanol and bio-dunder (which can be used as a liquid fertiliser).
Sugar Refining
Raw sugar is an intermediate product, which requires further refining before it can be used for human consumption or as an ingredient in the manufacture of food and beverages.
At the refinery, the raw sugar crystals are washed and dissolved in hot water. Carbon dioxide and lime are added to the melted sugar to remove remaining impurities. The sugar is filtered through cloth, then the remaining colours and impurities are removed and the pure sugar is boiled in a vacuum pan and seeded with fine sugar crystals. When the crystals are large enough they are tumble dried to remove moisture. The dried sugar is then graded into sizes ready for delivery to customers.
Australian refineries process raw sugar into white (refined) sugar and liquid sugar products and other speciality products such as Golden Syrup, treacle, coffee sugar and cube sugar.
Since the Queensland industry was deregulated in 1989 sugar refineries have been able to buy their sugar from Queensland Sugar Ltd or the New South Wales and Western Australian industries. All raw sugar used in Australian refining operations is sourced from within Australia.
Traditionally, sugar refineries were built in or near major urban centres but technological advances in the shipment of refined sugar have resulted in new refineries being built in cane growing regions.
Sugar Markets
Domestic Market
Around 20% of the raw sugar produced here in Australia is refined for domestic consumption and trade.
ExportsAround 80% of the raw sugar produced here is exported. Australia is the world’s second largest exporter of raw sugar after Brazil. We sell mainly to East Asia, China, Indonesia, Japan, Korea, Malaysia and New Zealand.
Bulk storage
Bulk sugar is transported in containers by either road or rail from the mills to the terminals, where it is carried by conveyor into the storage shed. When a ship arrives it is filled quickly with conveyors.
Queensland’s bulk sugar terminals can store more than 2 million tonnes of raw sugar, allowing year-round deliveries to refineries in Australia and overseas. Bulk terminals are located at Cairns, Mourilyan, Lucinda, Townsville, Mackay, Bundaberg and Brisbane.
Edible sugar products
The main products from Australia’s refineries are granulated sugars (ordinary sugar crystals), liquid sugar, golden syrup and treacle.
Sugar nutrition
Sugar plays an extremely important role in providing the energy necessary for our bodies to function properly.
Sugar is a type of carbohydrate. Other carbohydrate-rich food includes breads, cereals, fruit, rice, potatoes, legumes and pastas. Carbohydrates are the body’s preferred energy source.
During digestion, all sugar (and other carbohydrates) is broken down into simple sugar, glucose, which then travels through the blood stream to body cells. There it provides energy or is stored, as glycogen, in muscles or the liver for future use.
The key is to balance energy inputs (what we eat) with outputs (the energy we use) while recognising the importance of taste (treats we like) and nutrition (what’s good for us).
Since sugar has half the calories of fat (1 teaspoon of sugar contains only 20 calories where as 1 teaspoon of fat contains 45 calories), gram for gram sugar is less fattening. In fact the most recent research indicates that people who eat moderate amounts of sugar are less likely to eat as much fat, and vice versa.