You’ll need tasting glasses for each guest, one for each oil. Wine glasses or shot glasses work well, though professional tasters use small, lidded, dark glasses to conceal the oils’ color and concentrate their aromas. Offer water (sparkling and still) and, if desired, slices of green apple to clear the palate between tastes.
Pour a small amount of oil into a glass. Cover the top with one hand, and swirl the oil with the other to warm and aerate the oil. Next, remove your hand and immediately bring the oil right up to your nose. Inhale deeply. Record or articulate your impressions. Does the oil smell fruity? Vegetal? Herby or grassy? These are common descriptors.
Taste the oil. Does it have a pleasant viscosity, or is it heavy and mouth-coating? What flavors do you discern?
Does the oil seem well-balanced, or is it bitter or astringent? Is a peppery pinch evident on the finish? Do the flavors linger in your mouth, or is the finish short? Most importantly, do you like the oil?
To continue the tasting, offer the oils again with a variety of foods such as bread, cheese, meat, potatoes, and vegetables to illustrate the effect they have on the oils, or incorporate the oils into your dinner menu.