Virgin olive oil is obtained via mechanical olive pressing
processes alone, in such conditions as rule out all alteration of the oil. In brief, this means that, to be classified as a virgin olive oil, the product must not be treated otherwise than by
washing,
decantation,
centrifugation and
filtering.
Virgin olive oils are also classified on the basis of their free acidity content. This content is given as the percentage value of
oleic acid, which is the main kind of
fatty acid in olive oil. These acids are generally present in the triglycerides that make up the fats, forming a chain. However various factors may lead to their release,
free in the fat.
The increase in free acidity (which may come about in both in the olive and the olive oil) brings with it certain
modifications determining the formation of components
detrimental to the
organoleptic characteristics of the oil.