Fleur de sel, also known as flor de sal, is a type of artisanal salt that is carefully collected from salt pans. The process involves forming a very thin layer of salt crystals on the surface of the salt pan on hot and not windy days, which is then collected by workers and dried to produce the final product. This process is typically done using an underground stream that feeds a well, with the resulting salt being seven times saltier than the oceans. This artisanal method of salt production is considered to be a great natural resource in Ribatejo.