The physical, chemical and organic qualities of an oil depend on many factors : the olive variety, the soil and climate in which the olive is grown, the growing method, the date and method of harvest and the time between harvesting and oil extraction.
Oils are tasted in a covered blue glass, which captures its flavours and aromas and disguises the colour (which may prevent an objective assessment). Oil is tested at 28°C, which allows its full fragrance (with notes of fresh and dried fruit, vegetables and legumes) – tastes (bitter and sweet) and textures (smoothness, creaminess) to shine through, while allowing any negative factors (sourness, acidity or mould) to be detected.
Even a beginner can identify the different oils produced by young or mature olives, before beginning to appreciate and identify its more subtle qualities.