Each variety of olive has different characteristics. Some are smooth, some peppery or fruity, lighter or more intense. Oils produced from a single variety give the full flavour of the particular olive tree and the characteristics associated with its geographical climatic and soil conditions. For example a tree grown at 350m altitude in a fertile soil has totally different character from a tree grown near the sea in a sandy soil. Mountain oil has superior organoleptic properties.
Most oils available today are blends from different varieties and locations. This does not necessarily mean these oils are of poor quality. However, blended oils do not enable one to capture the unique qualities of a single variety of olive grown on Single Estate, just like in the case of blended Scotches versus Single Malts.