How to taste olive oil properly

Tasting olive oil takes about a minute and changes how you shop for it permanently. Once you know what fresh oil is supposed to do in your mouth, the difference between a lively bottle and a tired one stops being something experts talk about and becomes something you notice straight away.

Professional tasters follow a strict protocol, with coloured glasses so the colour cannot influence the verdict, and a vocabulary of dozens of descriptors. You do not need any of that. What follows is a home version that keeps the useful parts and drops the ceremony.

A note before you start

Taste on a neutral palate. Not straight after coffee, not after something sweet, and ideally not first thing in the morning when everything tastes sharper than it is. A sip of water and a bite of plain bread is enough to reset. And pour cold oil from the bottle rather than oil that has been sitting by the stove, because you want to taste the storage, not the kitchen's warmth.

The method

• Pour a small amount, about a tablespoon, into a cup or small glass.
• Cover the cup with one hand and warm it briefly in your palm.
• Uncover, then smell immediately: this is where most of the fruit shows up.
• Take a sip and draw air in across it, the way you would with wine.
• Swallow, then wait a few seconds for the finish to arrive.

The slurp feels odd the first time and there is no way around it. Pulling air through the oil sprays it across your palate and up towards your nose, which is where most of what we call flavour actually happens. Without that step you are mostly tasting bitterness on your tongue and missing everything else.

The three positives

Every good olive oil is described through three attributes: fruitiness, bitterness and pungency. None of them is a fault, and learning to tell them apart is most of what tasting is for.

Fruitiness is the smell of the oil: grassy, green, tomato-leaf, almond, artichoke or, with riper fruit, something closer to banana or ripe apple. Fresh oil always has it, and it is the first thing to fade as an oil ages. If an oil smells of nothing at all, that is not subtlety, that is age.

Bitterness sits on the tongue and arrives with the first taste. It is the same sensation you get from rocket or strong radicchio, and it comes from the polyphenols that also keep the oil fresh. A robust oil will be noticeably bitter; a gentle one barely at all. Neither is wrong. Bitterness is simply the oil telling you how concentrated it is.

Pungency is the peppery catch at the back of the throat, and it is the attribute people find most surprising. A really fresh, high-polyphenol oil can make you cough. Professional tasters count a one-cough oil as good and a two-cough oil as exceptional. That tickle is the same family of compounds that makes freshly cracked pepper bite, and it fades as the oil ages, which is why an old oil can taste smooth and still be past it.

Faults to notice

The main faults all come from problems with the fruit or the processing, and they have blunt names because they are blunt smells. Fusty smells of stagnant olives left too long before milling. Musty smells damp and mouldy. Winey or vinegary means the fruit fermented. Muddy is exactly what it sounds like. None of these should ever be in a bottle sold as extra virgin, and once you have smelled one you will not mistake it for character again.

Rancidity is in a category of its own because it is almost always a storage problem rather than a production one. It smells flat and waxy, a bit like old nuts or crayons, and it develops slowly in every bottle that sits in light and warmth for long enough. If you want to know what it smells like before you meet it in the wild, leave a splash of oil in an open glass on a sunny windowsill for a fortnight.

Describing what you find

You do not need the official vocabulary, just three questions. How does it smell? How bitter is it on the tongue? And how far back in the throat does the pepper reach? Write the answers down next to the name of the oil and you have a tasting note that will mean something to you in six months. Over time you will find you can tell a gentle, buttery oil from a green, aggressive one in the first second, and choosing between two bottles on a shelf stops being guesswork.