What should I look for when choosing olive oil?
My daughters laugh when I reminisce about a time, not so very long ago, when buying olive oil meant a trip to the chemist because you wanted to clean out your ears. What sheltered lives we poor Brits lived then, taking a first tentative package holiday to Torremolinos and squinting suspiciously at the tanned natives, glowing with health, as they doused everything in litres of this mysterious green-hued liquid. Had they not heard of marge?
Jump forward five decades or so, and we are much more blasé, and well aware of the huge contribution that this deceptively simple staple has made to our cuisine. We have also started to understand that like wine, olive oil varies tremendously depending on where it comes from. Few realise that there are more cultivars of olives than there are of grapes; to the natural variation in flavour between olive varieties, we can add the maturity of the olives before processing, the way the fruit is stored, the method of extraction and how it is stored.
Categories of Olive Oil
We have become used to the phrase ‘Extra Virgin Olive Oil’ and this is what is called for by almost every chef in every recipe they write. Indeed, it is the highest category of oil. Strictly speaking Virgin olive Oil is oil which has been mechanically extracted from the olives in a way that does not alter the oil in any way; solvents and other chemical interventions are strictly banned. The ‘Extra’ bit refers to the amount of oleic acid in the product: plain ‘Virgin’ Olive Oil contains between 0.8 and 2% oleic acid, ‘Extra Virgin’ contains under 0.8%. There is actually a third category of Virgin Oil, known as ‘Lampante’ – this was considered only suitable for fuelling lamps! Plain old ‘Olive Oil’ tends to be a blend of Extra Virgin oil with a third grade, known as ‘Refined’ oil. The latter is oil which has been ‘cleaned’ with solvents to remove unwanted or unpleasant flavours. Incidentally, don’t get hung up on the ubiquitous words ‘Cold Pressed’; if it’s Extra Virgin, it will, by definition, have been cold pressed.
It is often said that it’s a waste of good Extra Virgin Olive Oil to use it for frying, and that the strong flavour can overpower some delicate foods. I’d agree wholeheartedly with this, but my own preference, rather than reaching for an inferior ‘refined’ oil, is to choose a different sort of oil together - perhaps a really good rapeseed oil - better suited to the dish in question. On the subject of frying, the smoke point of olive oil (the temperature at which it burns) is somewhat lower than many other oils, making it unsuitable for high temperature frying.
What to look for in different oils
Continuing the analogy of wine that I referred to earlier, there really are no rights or wrongs in choosing the right oil for a particular job. I’m not going to tell you to drink only white wine with fish (a lightly chilled Fleurie anyone?), or only red with strong cheese (pass the Gewürztraminer!) any more than I’m going to suggest that one oil is better than another. What I would suggest however, is that to have only one oil available to choose from is akin to only drinking the same wine every day! Shake it up a little! With so many to choose from, and such widely differing characteristics, take time to select the oil that best matches a particular dish.
As with wine, there is a well-worn lexicon of terms often used to describe the qualities exhibited my olive oils:
Fruity: This is self-explanatory really, a lively and attractive hint of fruit; almost sweet on the palate; smooth and easy.
Grassy: Referring both to the taste and smell of the oil, similar to cut grass; ‘green’ in character. It is exemplified by young oils produced from olives that have not been allowed to mature to full ripeness.
Bitter: This may sound unappealing, and on its own it would be. But, as with many foods and drinks, when balanced by other flavours it is actually an important characteristic that adds to the interest of the overall flavour. Think of olive oil without a hint of bitterness as like a gin and tonic without a slice of lemon!
Peppery: Like bitterness, too much pepperiness is unpleasant, and again it is more notable in oils produced from immature olives. A little ‘heat’ at the back of the throat can make an oil more interesting, if it makes you cough, that’s probably a bit too far!
Nutty: As the olives are allowed to mature fully, the resulting oil will achieve a pleasant sweet character reminiscent of almonds. The nuttiness of an oil can increase somewhat with age.
There are countless other flavours which can be detected in good oils: look for citrus, tomato leaves, apples, pears, artichokes – the list could go on forever!
There are certain flavours that indicate badly made oil, or simply oil that has been badly stored or for too long: If you’re picking up rancid flavours, winey or vinegary notes, or musty, mouldy flavours, it’s time to ditch it and get another bottle.
Storing your oil
Olive oil doesn’t last for ever but will keep for several months if treated with respect. The things to avoid are excessive heat, light, moisture and air. Most good olive oil comes in dark bottles which afford it some protection from the light, but I’d always advocate keeping it in a cupboard rather than ‘on show’. Somewhere cool (that’s pantry cool, not fridge-cool – we’re all aware of the way olive oil can actually solidify in the fridge), around 15°c is ideal. And, keep it well stoppered! Rancidity is caused by the action of oxygen on oils and fats, keeping the lid on will help keep it at its best for much longer.