The tasting has two stages, aromatic and gustatory. In the first, any type of defect must be ruled out and the level of fruitiness scored. In the second, the bitterness and pungency in the mouth is assessed. 

For an official tasting, 120 ml blue glasses and a 60 mm diameter watch glass are used.

The procedure is as follows:

Fill 1/3 of the tasting glass.
Cover with watch glass for 5 minutes.
Hold the glass on the palm of the hand for 2 or 3 minutes to raise the temperature to 28 °C.
Uncover and take several deep whiffs.
Sip about half a teaspoonful of oil, letting it permeate your whole mouth and then swallow it. The operation should be carried out slowly so you can appreciate the aftertaste and pungency or pepperiness.
If you want to do a full tasting again, take a sip of water and eat a piece of slightly acidic green apple.