Cane sugar starts as juice locked inside tall, fibrous stalks of sugarcane, then goes through crushing, cleaning, boiling, and crystallization before it reaches your kitchen. The whole journey from field to finished crystal takes surprisingly few ingredients: sugarcane, water, lime, and heat. Here’s what happens at each stage.
Growing and Harvesting the Cane
Sugarcane is a tropical grass that grows 10 to 20 feet tall. Depending on climate, it takes 10 to 20 months to mature. During the final phase of growth, starting around nine months after planting, the plant slows its leafy growth and begins converting simple sugars like glucose and fructose into sucrose. Farmers time the harvest to catch the stalks at peak sucrose content.
Harvesting is done either by hand with machetes or by mechanical harvesters that cut the stalks near the base. Speed matters here: once cut, sugarcane begins losing sugar within hours as natural enzymes break down the sucrose. Most mills want cane delivered within 24 hours of cutting.
Brazil and India dominate global production. Brazil alone is forecast to produce about 44.4 million tons of sugar in the 2025/26 season, with India close behind at 35.3 million tons. Worldwide, total production is expected to reach roughly 189 million tons.
Crushing the Stalks to Extract Juice
At the mill, the first step is preparation. Rotating blades chop the cane into smaller pieces, then rotary shredders tear the stalks apart, breaking open the plant cells so juice can flow out more easily. This shredding step makes a significant difference in how much sugar the mill can recover.
The shredded cane then passes through a series of four to seven heavy roller mills arranged in sequence. Each set of rollers has three grooved cylinders positioned in a triangle, and they squeeze the cane progressively harder. Between roller sets, hot water (around 70°C) is sprayed over the crushed fiber to wash out any remaining sugar. This technique, called imbibition, pulls sucrose that the rollers alone would leave behind. By the end, the mill has separated the juice from the fiber.
The leftover fiber, called bagasse, comes out with about 50% moisture. It doesn’t go to waste. Most mills burn it in boilers to generate steam and electricity, making sugar production partially self-powering. Bagasse also finds second lives as paper pulp, particle board, animal feed, and even a natural water filter for removing contaminants.
Cleaning the Raw Juice
Fresh cane juice is murky. It contains bits of soil, wax, proteins, and plant pigments that all need to come out before crystallization can work properly. The primary cleaning agent is surprisingly simple: lime, or calcium hydroxide. Adding lime to the juice raises its pH, which causes many of the dissolved impurities and proteins to clump together into larger particles that can be filtered out.
The limed juice is then heated, which accelerates the clumping process. The heavy clumps, called mud or floc, settle to the bottom of large clarifying tanks. The clear juice is drawn off the top, while the mud is filtered to recover any remaining sugar before being discarded. This mill mud is rich in organic carbon, nitrogen, and minerals, so it’s often spread on fields to restore soil fertility.
Evaporation: Turning Juice Into Syrup
Clarified juice is still mostly water, typically around 85%. To get crystals, the mill needs to concentrate it dramatically. The juice passes through a series of large evaporators, each operating at a lower pressure than the last. Lower pressure means water boils at a lower temperature, which saves energy and prevents the sugar from browning or breaking down.
By the time the juice exits the final evaporator, it has thickened into a golden syrup with a sugar concentration of roughly 60 to 65 degrees Brix (a measure of dissolved solids). This syrup is now ready for the step that actually creates sugar crystals.
Crystallization in Vacuum Pans
Crystallization is the heart of sugar manufacturing. The concentrated syrup is fed into large vacuum pans, sealed vessels that operate under reduced pressure so the syrup boils at relatively low temperatures. As water continues to evaporate inside the pan, the syrup becomes supersaturated, meaning it holds more dissolved sugar than it can stably contain.
At this point, the operator introduces seed crystals: tiny grains of sugar or a slurry of finely ground sugar suspended in alcohol. These seeds give the dissolved sucrose something to latch onto, triggering crystal growth. Without them, impurities in the juice, particularly natural pigments and salts, would interfere with the sugar molecules’ ability to organize into crystals on their own. Research confirms that firm, stable crystals form once the syrup concentration exceeds about 68 degrees Brix, and the seeding process encourages uniform crystal size rather than a mix of large and tiny grains.
The operator carefully controls the feed rate of fresh syrup and the evaporation rate to grow the crystals to the desired size. This takes several hours. The result is a thick mixture of crystals suspended in a dark, viscous liquid called mother liquor, or massecuite.
Spinning Out the Molasses
The massecuite is dropped into centrifuges: spinning baskets with perforated walls, rotating at speeds between 1,000 and 1,500 RPM. Centrifugal force pushes the liquid molasses through the perforations while the sugar crystals stay trapped against the basket wall. A quick spray of water or steam washes any remaining molasses film off the crystals.
This process typically happens in stages. The first spin produces the highest-quality crystals. The molasses that spins off still contains a good amount of dissolved sugar, so it’s boiled and crystallized again to recover more. Mills commonly run two or three rounds of crystallization and centrifuging. Each successive round yields darker, lower-purity sugar and progressively thicker molasses. The final molasses, called blackstrap, has had most of its recoverable sugar removed and is sold for animal feed, fermentation into rum or ethanol, or as a food ingredient on its own.
Raw Sugar vs. Refined White Sugar
What comes out of the centrifuge at this point is raw sugar: tan or golden crystals coated with a thin layer of molasses. Raw sugar is a finished product in many markets and is what you see labeled as turbinado or demerara sugar. It’s edible and safe, just less pure and more flavorful than white sugar.
To make the white granulated sugar most people keep in their pantry, raw sugar goes to a refinery for further processing. The crystals are first dissolved in warm water to create a syrup, then put through two main decolorization stages. The primary stage uses either carbonation (bubbling carbon dioxide through limed syrup to form a chalk-like precipitate that traps color molecules) or phosphatation (a similar technique using phosphoric acid and lime). The secondary stage passes the syrup through activated carbon, bone char, or ion exchange resins, all of which adsorb the remaining pigments and trace impurities. The result is a nearly colorless syrup that is then boiled, crystallized, and centrifuged one more time to produce bright white crystals.
After a final drying and cooling step, the crystals are screened by size, packaged, and shipped. The entire refining process doesn’t add anything to the sugar or change its chemical identity. It simply strips away the color compounds, minerals, and organic molecules that gave raw sugar its golden hue.
Water and Energy Costs
Sugar production is water-intensive. The global average water footprint for sugarcane is about 209 cubic meters per ton of cane, which works out to roughly 1,500 to 1,800 liters of water for every kilogram of refined sugar when you account for field irrigation, processing, and losses. That’s lower than corn-based sweeteners but higher than sugar beet, which averages 133 cubic meters per ton of crop.
On the energy side, burning bagasse offsets a large share of a mill’s fuel needs. Some modern mills generate enough electricity from bagasse to power their own operations and sell surplus power back to the grid, turning a waste product into a revenue stream.