Choosing a good quality extra virgin olive oil requires care and attention, not just because oil is a fundamental, central ingredient of a Mediterranean-style diet, but above all because its production process and history make it one of the finest gems in the Italian gastronomic heritage. There are three factors to be considered when purchasing an oil, according to the Zucchi experts, to ensure you serve a good, healthy product of fine quality. Visual impression Watching how an extra virgin olive oil behaves when poured into a glass can provide useful information about its body and smoothness, although these parameters are not strictly connected to quality. First of all, pour a small amount of oil into a glass and try to assess its fluidity by looking at it against the light. The fluidity of extra virgin olive oil is medium-low, while high fluidity is typical of oils with a high polyunsaturated fatty acid content. Turn the glass round to see how the oil spreads over its sides and observe its colour. It may vary in colour from a bright green through to a tone closer to golden yellow. This depends on a variety of factors, especially the ripeness of the olives and the extraction method used. One danger signal for which you should look out is the presence of reddish glints, which mean that the oil may not have been protected from the light. Aroma Another major factor when choosing a good quality oil is the impression given by its aroma. Smelling an oil can give us a great deal of information about it, but before this delicate sniffing phase we need to ensure that the oil is in the right condition, so that all its volatile aromatic components can be appreciated to the full. Heat the contents of the glass with the palm of your hand, shaking it gently; the ideal temperature is 28°C.  After this, cover the top of the glass with your other hand to keep the aromas in, then take your hand off the top of the glass, lift it to your nose and inhale deeply to identify all the ingredients of the oil’s fragrance. We advise you to repeat these steps several times, since they will enable you to pick up the various shades of aroma present and establish their intensity on a scale of values ranging from “barely noticeable” to “very strong”. Flavour Tasting is one of the parameters used to assess an oil’s quality and it will enable you to identify a number of flavours, especially bitterness and sweetness. Our sense of taste is in our taste buds; our mouths are able to recognise foods’ flavour thanks to specific structures located throughout our oral cavities. The taste buds on our tongues enable us to identify bitter, sweet, salty, acid and umami. Sip a little oil and use your tongue to spread it around your mouth; first suck slowly and delicately and then more vigorously, trying to draw air into your mouth. This will enable you to memorise the sensations you feel and become familiar with the various flavours. Oil must not taste acidic (rather like wine or vinegar), earthy or metallic. Also, a good oil does not have an after-taste of cucumber or mould. However, a bitter or “hot” flavour (of the right intensity, of course) is not a negative feature but may actually be the key characteristic when choosing a good quality oil to add flavour to dishes of all kinds.