Olives were likely first domesticated in the Mediterranean basin some 6,000 years ago or so.

It is thought that oil from the olive was one of several attributes that likely made the bitter fruit attractive enough to result in its domestication.

However, the production of olive oil, that is to say, the deliberate pressing of oil out of olives, is currently documented no earlier than ~2500 BC.Olive oil was used for variety of purposes, including lamp fuel, pharmaceutical ointment and in rituals for anointing royalty, warriors and others. The term “messiah”, used in many Mediterranean-based religions, means “the anointed one”, perhaps (but of course, not necessarily) referring to an olive oil-based ritual. Cooking with olive oil may not have been a purpose for the original domesticators, but it began at least as long ago as the 5th-4th century BC, as described by Plato.

Making Olive Oil

Making olive oil involved (and still does) several stages of crushing and rinsing to extract the oil. The olives were harvested by hand or by beating the fruit off the trees. The olives were then washed and crushed to remove the pits. The remaining pulp was placed into woven bags or baskets; the baskets themselves were then pressed. Hot water was poured over the pressed bags to wash out any remaining oil, and the dregs of the pulp was washed away.The liquid from the pressed bags was drawn into a reservoir where the oil was left to settle and separate. Then the oil was drawn off, by by skimming the oil off by hand or with the use of a ladle; by opening a stoppered hole at the bottom of the reservoir tank; or by allowing the water to drain off from a channel at the top of the reservoir. In cold weather, a bit of salt was added to speed the separation process. After the oil was separated, the oil was again allowed to settle in vats made for that purpose, and then separated again.

Olive Press Machinery

Artifacts found at archaeological sites associated with making oil include milling stones, decantation basins and storage vessels such as mass-produced amphorae with olive plant residues. Historical documentation in the form of frescoes and ancient papyri have also been found at sites throughout the Mediterranean Bronze Age, and production techniques and uses of olive oil are recorded in the classical manuscripts of Pliny the Elder and Vitrivius. Several olive press machines were devised by the Mediterranean Romans and Greeks to mechanize the pressing process, and are called variously trapetum, mola molearia, canallis et solea, torcular, prelum, and tudicula. These machines were all similar, and used levers and counterweights to increase the pressure on the baskets, to extract as much oil as possible. Traditional presses can generate about 200 liters of oil and 450 liters of amurca from one ton of olives.