What is unrefined extra virgin vs virgin olive oil?

Olive oil is obtained by pressing olives by mechanical process to extract the juice of the olive. Extra virgin olive oil must be free of any defects with an acidity level less or equal to 0.8%. Extra virgin olive oil has the strongest aromas and flavours. These smells and tastes represent the environment the olives were grown in.

Virgin olive oil has less aroma and flavour as well as some defects. This is because the production process causes the fruit to deteriorate, leading to defects in the final result. Virgin olive oil must have an acidity level of less than 2.0%. Although virgin olive oil has a lot of the nutrients of extra virgin olive oil, it lacks in terms of flavour and overall taste. 

Major retailers will often sell olive oil products that display 0.1% acidity to portray a high quality product, when, in fact, this is because of the refining process that uses caustic soda to counter the acid. High quality extra virgin olive oils will have a natural acidity level of less than 0.3%.