Ethanol is one of the precursors of ethyl esters, the virgin olive oil quality parameter for the "extra" category recently adopted by the European Union and International Olive Oil Council. Although ethyl ester content has great importance for virgin olive oil classification, the origin of ethanol is not clear. A possible source of ethanol may be the olive fruit itself while it remains on the tree. Variation of fruit ethanol content during ripening was studied for three different olive cultivars: 'Picual', 'Hojiblanca', and 'Arbequina'. Ethanol was measured in fruit homogenates by HS-SPME-GC-FID. The ethanol content varied between 0.56 and 58 mg/kg. 'Hojiblanca' fruits showed the highest ethanol concentration. For all of the cultivars, ethanol content of fruit increased during the ripening process, although a clear cultivar-dependent effect was observed because 'Hojiblanca' fruits showed the most significant raise. Therefore, results indicated that ethanol can be accumulated during fruit maturation on the olive tree.

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The effect of two different clarification systems, vertical centrifugal separator (VCS) with minimal water addition, and conical bottom settling tank (CBST), on virgin olive oil (VOO) composition and quality was studied at industrial scale for three crop years. In general, for the studied clarification systems, higher clarification values were reached for horizontal screw solid bowl (HSSB) oils with higher moisture and solid content. VCS showed higher clarification efficiency for HSSB oils with higher moisture and solid content. No notable differences were observed on the quality indices between evaluated clarification systems. Phenolic compounds showed a significant decrease when the HSSB oils were clarified by CBST. In general, a better sensory score was observed when the oils were clarified by VCS. Practical applications: The VCS with a minimal water addition could result a better option to produce VOO of improved quality, since is an efficient and quick operation that reduces the contact between oil and the remaining water and impurities content during the storage stage. This leads to prolong VOO shelf‐life and conservation of positive sensory notes, due to preservation of the quality indexes and minor components. Besides, this clarification system reduces the water consumption and generated wastewater regarding to conventional vertical centrifugation, and therefore can be considered more environmentally friendly. Effect of two different clarification systems (vertical centrifugal separator with minimal water addition and conical bottom settling tanks) on the virgin olive oil quality parameters, composition, and sensory characteristics.