More than 2,000 years before film director Fritz Lang created “Metropolis,” his stark futuristic account of an underground factory town, workers at Maresha slaved away in subterranean plants, producing olive oil for export to Egypt. The drawing (below) depicts one of the site’s 22 remaining underground olive oil factories—complete with a crushing basin in the foreground and two presses against the rear wall (the drawing shows only the stone remains of the presses; a reconstructed press, with stone weights hanging from a horizontal beam, appears in the below photo). During the Hellenistic period (332–112 B.C.E.), residents squeezed approximately 300 metric tons of olive oil a year.
In the autumn, inhabitants of Maresha harvested olives from the orchards that once grew in the valleys and on the hills surrounding their city. The fruits were then brought underground and placed in round crushing basins measuring 5 to 6 feet in diameter (see photo, below). A lens-shaped stone (orbis in Latin, memel in Hebrew), resting on its edge, reduced the olives to a pulp. A man (or perhaps a donkey) rotated the stone by pushing or turning a short horizontal beam through the center of the stone.
The crushed olives were then poured into flexible wicker baskets and stacked beneath a press (first photo). A horizontal wooden beam with three stone weights (about 800 pounds each) pressed the oil out of the olive pulp. Measuring 15 feet or longer, the press beam fit into the wall on one end and passed over two stone-carved press-piers with a drainage basin or collection vat hewn into the rock beneath them.
After a mixture of olive oil and water was pressed from the crushed olives, the weights were detached, the beam lifted and the baskets removed from the piers. The liquid was conveyed into the drainage basin. These basins were usually plastered to prevent seepage of the oil into the porous bedrock.
Archaeologists at Maresha found numerous juglets designed to skim pure oil off the water.
Cultic niches (below photo)—possibly dedicated to the Edomite god Qos or to a Greek deity—found throughout the factories may have been used in religious rituals designed to increase olive oil production.