The sugar series: sugar cane production
February 21, 2020
Close-up shot of green sugarcane

Sugar is one of the world’s purest natural ingredients and is used globally and in almost every food category.

Grown in over 100 countries, over 170 million metric tons of sugar is produced each year. But how is it extracted from sugar cane and processed into pure sugar? Our team of sugar market analysis experts delve deeper to provide more insight on sugar cane production and the steps taken from planting to refinement. Discover more about sugar trading from the experts at Czarnikow.

We break down the production of sugar cane into 6 key steps:

1.How to Grow Sugar Cane
2.Harvesting Sugar Cane
3.Total recoverable sugar (TRS)
4.How to process sugar cane
– Extraction
– Clarification
– Boiling
– Crystallisation
– Centrifuging
5.Raw Sugar
6.Refined Cane Sugar

How to grow sugar cane

Sugar cane is grown in warm to tropical areas of the world, with Brazil, India, Thailand, China and Australia as the leading global producers of sugar cane. Each sugar cane farm has multiple fields – all at different stages of production to ensure that there is always cane available to supply the mill. From planting the cane through to harvest, the process can take up to 18 months; making sugar cane quite a slow crop to produce. For this reason, preparation of the cane ahead of it being planted is vital.

The leaves are removed from the cane and then cut into 20cm ‘tranches’. The field row is then prepared with incisions made in the field at approximately 15-20cm in width. The cane is then placed inside the hole horizontally and left to grow.  The success of producing sugar begins with healthy soil. This is done with the addition of nutrients and lots of water.

Sugar Cane takes approximately 12-18 months to mature fully. During this time, it is important that the cane is treated with pesticides and fertiliser to enable a healthy and high yielding cane plant.

Harvesting Sugar Cane

Cane sugar does not need to be re-planted, as only the top of the plant is removed during harvest. There are two ways that sugar cane can be harvested – manually or mechanised.

The manual harvest process often begins with the sugar cane fields being burnt. This removes all the leaves so that the cane can then be manually chopped to the ground by a team of farmers. However, this process takes days and the burning of the cane leaves results in wildlife and a reduction in the quality of the sucrose in the cane. There has also been recent controversy relating to sugar cane burning in Thailand, a practice which has caused a rise in pollution. We hope to work with farmers through the VIVE Programme to support them with the sugar cane harvester machinery they would need to harvest without burning. Once the cane has been manually harvested, it is put on a truck by hand and driven to the mill.

The alternative way to harvest sugar cane – the mechanised harvest – involves a machine extracting the cane as it travels across the field, whilst loading it into a truck. Mechanised harvesting is seen as the future of cane harvesting. This is primarily because it is not only better for the environment and wildlife, but it is a more efficient operation taking the cane to the mill. Mechanised harvesting reduces the time of an average harvest by up to three-quarters, from 24-36 hours to only 6-12 hours. This increase in efficiency for the harvest means higher sucrose yields and larger profits for the plantations.


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Total recoverable sugar (TRS)

Once the sugar cane is transported to the mill, it has to be weighed and examined to confirm how much cane has been delivered, and to determine the TRS (Total Recoverable Sugar) content of the cane, and also the quality of the cane. This has a direct impact on the price it will be sold for.

How to process sugar cane

At a sugar mill or facility, sugar cane undergoes the first of two possible stages of processing. The end result is raw sugar, which is pure sugar with some molasses content remaining. Molasses is a by-product of sugar, and is what gives raw sugar its brown appearance. Sugar cane processing at a mill requires a few stages to get sugar from sugar cane, and we will go through in them more detail below:

Extraction

Once the cane has been graded, it is washed to remove any impurities ahead of being processed. The cleaning of the cane can be done wet or dry. Dry cleaning is the preferred method as it is more environmentally friendly and does not affect the TRS content.

After the cane has been dried, it is chopped before it is crushed in big roller mills. This process removes the sugar cane juice. The juice is the valuable extract as it is used for sugar and ethanol production. The sugar cane waste, which is known as ‘bagasse’, is then used as fuel to generate electricity in the power plant.

Clarification

The sugar cane juice is then sent for clarification. The juice is treated for precipitate elimination via coagulation and sedimentation. The process removes sand, clay and other substances from the juice. Nearly 90% of the weight of sugar cane is juice, which contains up to 17% of sucrose (common sugar) and small amounts of dextrose and fructose.

The avoid sucrose decomposition, the juice then passes through a process of pH correction. Once this has been done, the juice is mainly water, mineral salts and sugars.

Boiling

The juice goes through a boiling process, where moisture is boiled off. During the boiling and evaporation process around 75% of the water is removed, resulting in a thicker syrup concentrate.The syrup is then cooked so that crystallisation and recuperation of the sucrose can take place.

Crystallisation

The syrup is placed in large vessels where it is rotated slowly, allowing it to cool evenly. Seeding is then carried out, where small seed crystals are added to the syrup to catalyse the crystallisation process. The molasses separates from the crystals, and the liquid is ready for the next stage.

Centrifuging

To complete the process, centrifuging then takes place. During this process the crystallised syrup is separated from the sugar and dried by being put into centrifuges. This produces raw sugar by separating the sugar crystals from the surrounding molasses.

For every 100 tonnes of cane that is processed, about 12 tonnes of VHP (Very High Polarity) sugar is produced and 4 tonnes of molasses.

The amount of molasses, which is leftover solution from the sugar processing, that is left on the crystals or added back to the sugar crystals determines what type of sugar is produced.

In addition to white granulated sugar, there are light and dark brown sugars that have a higher molasses content and are often produced for speciality use. Typically at this stage, the cane sugar is not food grade.


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Refined Cane Sugar

When the sugar has been produced from the sugar cane, it is then ready to leave the mill. Some of the sugar will be sold to a sugar refinery for further purification, which through another set of processes turns raw sugar into refined sugar. You can read more about this in our blog on refined sugar production. This is a common route of travel for raw sugar, as many types of food and beverages, most notably confectionary, use refined sugar in their recipes. Refined sugar can be made from either cane sugar, which we have covered in this blog, or beet sugar, which you can find out about in this blog.

Raw Sugar

There is also a large global raw sugar market. Any cane sugar destined for this route will be taken from the sugar mill to a terminal or port, to be delivered directly to an industrial client for use in its products. Under a traditional FOB (Free On Board) contract, it is the obligation of the seller to organise transport of the raw sugar from the mill to where it is required, often involving long journeys by truck, rail and ship. Normally the sugar would need to travel to a port, where it would then be loaded onto a bulk freight ship chosen by the buyer.

However, increasingly at Czarnikow we are working to buy sugar directly from producers at their factory gates, so that we can pay them quickly and take on the logistical responsibility on behalf of our clients from that point, enabling us to offer a holistic supply chain service.

In other articles on our site you can find out more about the top sugar producing countries, or how sugar beet is made. You can also speak to a sugar trading expert to find out more by contacting one of our team.

Author: Rebecca Spencer

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