An Original Olive Oil from an Exceptional Origin

Manufacturing Methods

Grinding of Olives to Paste

Stone Olive Mills

Stone rollers or wheels roll in circles on a slab of granite to grind the olives into a paste.

Advantages

can be adapted to olive and pit size to optimise paste characteristics
doesn't cut the skin, releasing less chlorophyll so less bitter oil
formation of larger size drops of oil, minimizing mixing times
paste isn't heated

Disadvantages

bulky
stone is difficult to clean
green olives will prolong grinding time
costly
discontinuous process - time consuming
high labour cost

Hammer Mill

A hammer mill has swinging arms which through centrifugal action push the olives into the sides of a rotating chamber, similar to a home garbage disposer. The mill may have one to several hammers.

Advantages

continuous
high throughput
Tolerates debris such as rocks and grit
know, perfected technology
extracts more phenols so oil has longer shelf life

Disadvantages

may form emulsion which impedes oil - water separation
organoleptic characteristics affected - oil can have bitter, stronger, spicy taste due to more phenols
wear and tear of metal parts
oil paste may heat up

Oil Separation

Centrifugal Decanters

Spins the olive paste in a horizontal drum; the heavier flesh and pits goes to the outside and the water and oil is tapped off from the centre.

Advantages

Compact machinery - one decanter can take the place of several presses
semi continuous and automated
limited labour

Disadvantages

expensive
more technical labour required
may consume hot water
high energy consumption
pomace may end up moist
greater amount of vegetable water to be disposed of
reduced antioxidants due to added water
subject to wear from rocks, grit

Sinolea Method

Rows of metal discs or plates are dipped into the paste; the oil preferentially wets and sticks to the metal and is removed with scrapers in a continuous process.

Advantages

higher polyphenol content of oil
low temperature method
automated
low labour
oil/water separation step is not needed
low energy requirement

Disadvantages

Often must be combined with one of the above methods to maximize oil extraction which requires more space, labour, etc.
Large surface areas can lead to rapid oxidation