A brief history of Marseille French Soap
Traditionally, the soap is made by mixing sea water from the Mediterranean, olive oil, and the alkaline chemicals soda ash (sodium carbonate) and lye (sodium hydroxide) together in a large cauldron. This mixture is then heated for several days, stirred constantly. The mixture is then allowed to sit and, once ready, it is poured into the mold, and allowed to set slightly. Whilst still soft, it is cut into bars and stamped, and left to completely harden. The whole process can take up to a month from start to finish.