Puglia is geologically formed by limestone layers and the waters have formed underground caverns. Following these caves were dug by people to be used as dwellings or housing of livestock or as places of worship.

The monks, later, introduced the systems of the olives in tombs to defend against looting.

In the phase of processing of olives and oil during storage was necessary that there were no changes in temperature to maintain the integrity of the quality of the product.

The Frantoio Ipogeo ensured a constant temperature inside at 20 ° C

The low winter temperatures would not allow a good grinding of the olives or the oil would be sufficiently fluid to drip off the presses and decant. To increase the ambient temperature the fire was burning night and day in the kitchen.

The tank of the milling was placed at the center and sides of the presses; Outside there was a wide space for depositing the olives and the same were dropped  in correspondence of the mill with a hole opening on the floor.

The oil extraction has two stages, the grinding and pressing of the dough.

The grinders were rotated by animals (donkeys) with a rudder, you could work tons of olives obtaining a paste with which were filled except straining rush.

The presses were based on a fixed place on a stone floor and overlapped 20-25 fiscoli (filters) stacked, two or three workers were off the press by pressing the dough.

The two most common types were 'the Calabrian' and 'Genovese', both vertical and driven by force of arms.

The first was composed of two large piles of hardwood, threaded, firmly fixed in the top and bottom.

The second type of press, what 'Genovese', was very similar to the previous operation, with the difference that had to be mounted in a recess formed by a wall.

In the vicinity of the presses a system of channels collecting the oil, channeling it in large underground tanks, where it was left to decant for the time necessary, up to the time of the "cut" in which the separation occurred from oil to impure waters.

From the first pressing was obtained 80-90% of oil, while the residue that remained in fiscoli (filters) still contained a quantity of oil that was again worked with addition of hot water by providing a quantity of oil 5-6%

After first settling in the wells, the oil further extolled in wooden vats with separating the vegetable water and was transferred to other tanks.

The residue was used as fertilizer.

Around the kitchen there is the base where the workers slept. The shifts were continuous because they worked in one cycle.

Olive oil is still the most famous product of the territory of Ostuni. The variety most representative is the 'Ogliarola they belong to the most majestic plant olive trees.