Reconstruction of how an olive press probably worked. Olives were first crushed with heavy stone rollers in the central basin, a shallow stone trough. This extracted the finest oil. To obtain additional oil, workers then placed the pulp in flat straw baskets, stacked the baskets on the vats, topped them with a stone, and then applied pressure to the stack of baskets by a beam anchored in a niche in the wall and weighted with stones. A stone weight (see photograph) typically weighs about 140 pounds; the hole that penetrates it allowed the weight to be attached to the beam with a rope. As pressure was applied to the baskets, oil was squeezed from the pulp, through the loosely woven baskets and into the vats.