Turning sugarcane into sugar is a multi-step process of extracting juice, removing impurities, and boiling off water until sucrose crystals form. Industrial sugar mills process millions of tons of cane each year this way, but the core logic is simple enough that small-scale producers around the world make solid sugar (jaggery, panela, or muscovado) with little more than a crusher, a pan, and a fire. Here’s how the process works at every scale.
Crushing and Extracting the Juice
Sugarcane stalks are tough and fibrous, so the first job is to break them open and squeeze out the sweet liquid inside. At a mill, this happens in two stages: first, revolving knives or shredders break the hard structure of the cane, then multiple sets of heavy three-roller mills grind it further. Conveyors move the crushed cane from one set of rollers to the next, and at each pass, more juice is pressed out.
To get as much sugar as possible, mills spray water or recycled juice onto the crushed cane between roller sets, a step called imbibition. The water dissolves sugar still trapped in the fiber, and the next set of rollers squeezes it out. What’s left after all that crushing is bagasse, a dry, fibrous pulp. Most sugar factories burn bagasse as fuel to power the boiling process, though 15 to 20 percent often goes unused at some facilities.
At a small scale, the same idea applies. Two- or three-roll crushers powered by a small engine, or even a single ox, can process around 50 kilograms of cane per hour. Street vendors across South and Southeast Asia use manually powered horizontal crushers to press fresh cane juice for drinking. The key difference is volume: a factory processes thousands of tons per day, while a small crusher handles a manageable batch.
Clarifying the Juice
Raw sugarcane juice is cloudy, greenish-brown, and full of plant matter, waxes, and minerals that need to come out before you can make clean sugar. In commercial processing, the primary tool is lime (calcium oxide). Adding lime raises the pH of the juice and causes impurities to clump together into large particles that settle to the bottom or float to the top as a thick scum. The interaction between lime, natural phosphates in the juice, and sucrose is what drives this separation. Some factories use a two-stage process, first adding lime and then a second alkaline agent, to reduce the buildup of mineral deposits on equipment further down the line.
Small-scale producers handle clarification more simply. Filtering the juice through a cotton cloth catches dirt and cane particles. Letting the juice sit for a few hours allows fine sediment to settle out naturally. During boiling, scum rises to the surface and can be skimmed off with a long-handled fine-mesh ladle or a cloth passed through the liquid. Some artisanal producers add wood ash as a clarifying agent, which works on the same principle as lime by raising alkalinity.
Boiling and Evaporating the Water
Clarified juice is mostly water, typically around 80 to 85 percent. To turn it into sugar, that water has to go. In a factory, the juice passes through a series of large evaporators operating at around 117°C and elevated pressure. Each evaporator removes more water, concentrating the liquid until it reaches about 65 degrees Brix, meaning 65 percent of the solution is now dissolved sugar. Below about 58 degrees Brix, no sugar crystals will form, so hitting that concentration threshold is essential before moving on.
For small-scale production, this step is straightforward: boil the juice in an open pan over a furnace. The most basic setup is a furnace built into the ground with a low brick or stone wall around the top to support a large flat pan. Two holes in opposite sides serve as a fuel feed (for bagasse) and a smoke exhaust. The juice is boiled steadily, with continued skimming, until it thickens into a heavy syrup.
Crystallization: Where Sugar Becomes Solid
This is the step that separates granulated sugar from simpler products like jaggery or syrup, and it’s where industrial and artisanal methods diverge most sharply.
In a factory, the concentrated syrup moves into a vacuum pan, a sealed vessel that lowers the boiling point by reducing pressure inside. Boiling at lower temperatures prevents the sugar from caramelizing or breaking down. Tiny seed crystals are introduced into the syrup. These seeds provide a stable surface for dissolved sucrose to latch onto, dramatically increasing the rate of crystallization. Without them, syrup can become highly supersaturated without forming crystals at all. Over time, the crystals grow as more sucrose deposits on their surfaces, producing a thick mixture of crystals and syrup called massecuite. Controlling the vacuum pressure precisely determines the final grain size: tighter control yields more uniform, finer crystals.
Small-scale producers making jaggery or panela skip controlled crystallization entirely. They simply boil the juice until it reaches a strike temperature between 116 and 120°C, then pour the thick, concentrated mass into molds. It sets into a dense, solid block as it cools. The result is a whole, unrefined sugar that retains molasses and minerals. To make something closer to granulated sugar at a small scale, the hot syrup can be stirred vigorously as it cools, which encourages smaller crystals to form and produces a crumbly, grainy product like muscovado.
Spinning Out the Molasses
Factory-produced sugar crystals are still coated in a layer of dark, sticky molasses. To separate them, the massecuite is loaded into a centrifuge: a rapidly spinning cylindrical basket with perforated walls. At speeds of around 1,300 to 1,500 revolutions per minute, centrifugal force flings the liquid molasses outward through the holes while the sugar crystals stay inside. Water and steam are introduced during the latter part of the spin cycle to wash remaining molasses off the crystals. Adding steam alone can increase molasses drainage by about 50 percent.
The molasses collected from centrifuging is itself a valuable product. It’s used in animal feed, fermented into ethanol and other biofuels, and used as a flavoring ingredient. The sugar left in the basket at this point is raw sugar: tan-colored, crystalline, and ready to be shipped to a refinery or sold as-is.
Refining Into White Sugar
Raw sugar still contains color compounds and trace impurities that give it a golden hue. Refining removes these. The raw crystals are dissolved back into a liquid, then passed through filtration systems that strip out color. Granular activated carbon is the most common filtering agent: it adsorbs color molecules as the liquid passes through, reducing the color to within a narrow industrial target. Some refineries use ion exchange resins for the same purpose. After decolorization, the clear liquid is re-crystallized, centrifuged, and dried to produce the white granulated sugar sold in stores.
White sugar is 99.9 percent sucrose with only trace amounts of calcium, iron, potassium, copper, and manganese. Less refined versions retain more of the original cane’s nutrients. Evaporated cane juice, for example, contains about 32.5 milligrams of calcium, 162.8 milligrams of potassium, and 0.6 milligrams of iron per serving, along with small amounts of magnesium, riboflavin, and niacin. These numbers are modest in the context of a whole diet, but they explain why many bakers and cooks prefer raw or minimally processed sugars for flavor depth as much as nutrition.
Making Sugar at Home
You won’t replicate factory-grade white sugar in a kitchen, but you can absolutely make a block of jaggery or a batch of cane syrup with fresh sugarcane and basic equipment. The process follows the same four stages used by artisanal producers worldwide: extract, clarify, boil, and mold.
Start by feeding your cane stalks through a hand-cranked or motorized crusher. If you don’t have a crusher, you can cut the cane into short sections, pound them with a mallet, and press the juice out through a cloth. Strain the juice through cheesecloth or a fine cotton towel to remove particles. Let it settle for an hour or two if you want clearer results, then pour off the top liquid.
Bring the juice to a boil in a heavy-bottomed pot, skimming off the foam that rises. Keep it at a steady boil, stirring occasionally to prevent scorching. As the water evaporates, the juice will darken and thicken. This can take several hours depending on volume. When a candy thermometer reads between 116 and 120°C, the syrup is ready. Pour it into greased molds for solid jaggery, or stir it continuously as it cools to produce a crumbly, grainy sugar. Stored in an airtight container, homemade cane sugar keeps for months.