On the Caribbean islands, sugar was the main crop. A hard year's labour planting, weeding, cutting and processing produced barrels of raw, muscovado sugar. Shipped to Europe, this was processed further to make cones or loaves of white sugar. There were 20 sugar houses in Bristol in 1760. The raw sugar was boiled and clarified, and the sugar syrup poured into earthenware moulds to crystallise out. As the sugar crystallised, the surplus syrup and molasses drained out of the bottom of the mould. Syrup, molasses and rum were by-products of sugar processing.