A sugar refinery is a refinery which processes raw sugar from cane or beets into white refined sugar. Many cane sugar mills produce raw sugar, which is sugar that still contains molasses, giving it more colour (and impurities) than the white sugar which is normally consumed in households and used as an ingredient in soft drinks and foods. While cane sugar does not need refining to be palatable, sugar from sugar beet is almost always refined to remove the strong, usually unwanted, taste of beets from it. The refined sugar produced is more than 99 percent pure sucrose. Many sugar mills only operate during the harvest season, whereas refineries may work the year round. Sugar beet refineries tend to have shorter periods when they process beet than cane refineries, but may store intermediate product and process it in the off-season. Raw sugar is either processed and sold locally, or is exported and refined elsewhere. History Sugar refineries date back to Arab Egypt in the 12th century. An artisanal version is the trapiche, later substituted by the engenho or . The British refining industry started in 1544 and was centred in the ports of Glasgow, Liverpool, Bristol and London. The risks involved in large refineries stimulated developments in the insurance industry. There were 16 fires in Greenock refineries between 1859 and 1895. Tate & Lyle became Britain's dominant refining company in the 20th century, but sold its sugar refining business in 2010 to American Sugar Refining. Sugar refineries are often located in heavy sugar-consuming regions such as North America, Europe, and Japan. Since the 1990s, many state-of-the art sugar refineries have been built in the Middle East and North Africa region, e.g. in Dubai, Saudi Arabia and Algeria. The world´s largest sugar refinery company is American Sugar Refining with facilities in North America and Europe. Raw sugar processing Affination The raw sugar is stored in large warehouses and then transported into the sugar refinery by means of transport belts. In the traditional refining process, the raw sugar is first mixed with heavy syrup and centrifuged to wash away the outer coating of the raw sugar crystals, which is less pure than the crystal interior. Many sugar refineries today buy high pol sugar and can do without the affination process. Purification In the purification step, the juice is mixed with hot milk of lime (a suspension of calcium hydroxide in water). This