Beet sugar processing - From beet to thin juice

Of the 175.5 million metric tons of sugar (sucrose) produced in 2024–2025, 20% is derived from sugar beets and 80% from sugarcane. In both cases, from the start of the supply chain to the production of the final sugar, the goal of sugar refineries is to start with the purest possible raw material and produce high-quality sugar with optimal yield. Sugar refining is therefore primarily an industry of separation and purification. A large number of unit operations for separation are thus carried out, for example, in beet sugar refineries:

• The washing facility removes impurities from the surface of the raw material;

• diffusion extraction limits the transfer of impurities into the juice;

• carbonate precipitation removes some of the dissolved impurities;

• multi-effect evaporation removes most of the water from the juice;

• Finally, crystallization allows sucrose to be separated as a pure crystal from a syrup that still contains impurities. The non-crystallizable syrup is used in the fermentation industry to produce alcohol or yeast, or active ingredients for the pharmaceutical industry.

The entire process is specifically designed to minimize environmental impact, whether in terms of resource consumption (energy, water, and other raw materials) or emissions (liquid and gaseous). Sugar refineries typically have very large production capacities and high levels of automation.

The primary objective of this article on processing methods in the sugar industry is to illustrate the integration of a large number of unit operations. For the sake of brevity, it focuses on sugar production from sugar beets (with France being the world’s second-largest producer in 2024–2025) and describes the operating parameters used in French factories. The first part of the article [F 6 150] describes all operations, from beet reception to the extraction of juice prior to evaporation, including the utilization of co-products and the treatment of waste. The second part [F 6 151] describes the stages from pre-evaporation juice to crystallized and packaged sugar, with a particular focus on energy optimization throughout the entire process and the crystallization stage. A few points distinguishing the sugar production process from beet versus cane are mentioned at the end of the article, which concludes with a look toward the...