A batch of olive oil soap can take up to a month to produce. The formula has not varied over the centuries, despite the availability of modern chemical compounds now found in most manufactured soaps. Ingredients (virgin olive oil, water, and a sodium compound) are mixed in a large vat over low heat for approximately five days, before the mixture is poured over a large floor space. Shortly afterward, casts are laid down to cut the soap into individual blocks, which are then stamped with the traditional seal of the factory of production. Once the soap is cut into blocks, it is stacked in geometric towers which allow for air circulation that assists in the drying process. The towering pyramids of soap climb to heights of over eight feet, and line the halls of the factory’s drying room for a period of between ten and thirty days, before they can be packaged and shipped.
In the city of Nablus, the tradition of olive oil soap-making evolved into a major industry and an art. As early as the 10th century, the traditional olive oil soap from the city’s factories was exported across the Arab world, and as far a field as Europe, where it is said that sabon nabulsi was the soap of choice for Queen Elizabeth of England.