In the tanks of the Sérail soap factory, the master soap maker produces two types of soap: one white, the other green.
  
The first is made of vegetable oils (coconut, palm). 
The same oils can be found in the other, but in small quantities to leave room for 50% olive oil.

Between the two tanks or cauldrons of soap (one for the white and one for the green), the soap maker supervises the cooking.
  
The first step involves mixing the vegetable oils with the alkali and then the sea salt. First, the mixture is boiled by steam circulating at the bottom of the tank in a coil. By chemical reaction, the alkali transforms it into a paste and it is purified by the salt.
  
This is called pasting, an operation that takes approximately eight hours.

Cooking involves boiling the paste for four hours at approximately one hundred degrees while frequently removing the used alkali.

This is followed by a washing cycle. The top of the cauldron is sprayed with cold water. As the water is heavier than the paste, it sinks to the middle and flushes away the impurities.

The soap maker must be very alert the whole time: the paste in boiling, and just like milk in a pan, it can suddenly boil up. When that happens he stirs the paste with a long stick to reduce it again.

After three or four days, the soap maker tests the soap to see if it is ready by putting a drop on the end of his tongue!

If it is sweet, he can go on to the next step. Otherwise, the paste needs to be re-washed.
  
Once the cooking is over, the soap maker turns off the heat and the tank is covered with planks of wood to keep it hot.

The paste is then left to rest for thirty-six hours.

While the paste is resting, the soap makers are busy
	downstairs preparing the moulds to suit the order, and they are then covered with strips of paper. Meticulously, the runners are installed. They link the bottom of the cauldron to the mould. One soap maker releases the paste, slowly at first to make sure that the runners are correctly in place.
At the same time he sticks the paper covering the wooden separations using liquid soap and a trowel. This seals the mould.

On the surface of the mould, the blocks are traced with a compass and then cut. The soap makers always work in pairs as they have to lift blocks that weigh 40kg.
  
The blocks are piled onto a truck and then placed on the cutting machine table. They are thrust mechanically between the frames of taught steel wire that cut them to form the traditional cubes of Marseilles soap.

The cubes are delicately placed on wooden racks fitted with casters. There they will be left to dry out slowly for two weeks.
  
The soap maker always takes care to leave a space between the blocks of soap so that the air can flow and to give him room to turn them one by one by hand.

The last operation involves stamping the soap before it goes to sale. With a regular, automatic gesture, the soap maker places each soap in the centre of a mould of a machine that is over a century old and which, as it closes, prints the various logos on the hardened soap paste.
Once packed, the bars of soap are now ready to be sent off to buyers.

As we have just seen, the creation of Marseilles soap involves many operations performed by hand.
  
At the Le Sérail factory, it is almost as if time has stood still as far as the production methods are concerned, as they have been used now for three-hundred years.
  
But that is the price to be paid for truly authentic, traditional soap of outstanding quality.