The world of olive oil is surprisingly complex and, like wine, full of complexities. Here’s a beginner’s guide to this fundamental element of Chanukah festivities.

What’s an olive?
Despite their savoury flavour, olives are fruits. Dr Simon Pool of Cambridge University and author of The Oil Olive Diet, explains: “Extra virgin olive oil is essentially a freshly squeezed fruit juice.”

Like wine, the appearance, taste and “mouth feel” come from a number of factors: the variety of fruit you’re using, where it’s grown, when it’s picked, and how soon and naturally the juice is extracted. There are hundreds, maybe thousands of olive varieties, each with a unique flavour profile, from spicy to sweet, smooth to bitter. Only 100 or so are grown commercially. One of the most popular — arbequina — originally hails from Israel.

According to legend, the Duke of Medinaceli, who lived in the castle of Arbeca, brought it back from Palestine to Spain in the 17th century. The Duke encouraged its cultivation throughout the Spanish empire and arbequina is now one of the most widely grown varieties in the Mediterranean and beyond.

Virgin, extra virgin and all that. What’s the difference?
There are three grades of olive oil — extra virgin (EVOO), virgin, and everything else, aka “olive oil”. EVOO must be pressed within 24 hours of picking and contain no additives.

Virgin must also have no contact with chemicals or heat but can be made with less perfect olives more than a day old. After the EVOO and virgin oils have been extracted, what’s left behind — pits and bits, leaves and skins — is known as pomace.

The oil from that is the lowest grade, lampante, which, as its name suggests, was traditionally used for oil lamps. To make lampante palatable, it’s chemically refined, mixed with a bit of virgin oil and sold as olive, light olive or pomace oil.

Why the 24-hour rule?
The moment you pick an olive its fresh, fruity flavours start to deteriorate as its free fatty acids, or FFAs, begin to form. The decline accelerates if the fruit is damaged.

Like EVOO, plain virgin oils are chemical-free but lack its delicacy and finesse because the olives may have defects or have been pressed beyond that 24-hour limit. Some are blended with EVOO to boost the flavour then sold as pure or classic olive oil.

Do olive oils of the same grade taste the same? In one word — no. Like wine, differing climate, soils and olive varieties have a huge effect on the finished oil and its uses. Green, grassy, slightly bitter Italian oils are perfect on roasted vegetables, while the peppery oils of Crete complement robust flavours such as feta or a tangy tomato salad. Golden, fruity, Spanish oils are unexpectedly delicious in cakes and in ice cream.

Even within a country, oils can vary — Tunisian oil from the mountainous north tastes quite different from that produced in the semi-arid south.

Is olive oil healthier than regular vegetable oil?
A staple of the Mediterranean diet, we now know that extra virgin olive oil is one of the healthiest things you can include in your diet, thanks to its high levels of polyphenols, particularly in bitter varieties such as picual.

“There is increasing evidence that shows extra virgin olive oil alone has positive measurable effects on health,” observes Dr Pool. “To be able to identify so many benefits in a single ingredient is quite remarkable and unique.”

Nutritional therapist and retired GP Dr Jacqueline Rose agrees: “Olive oil is naturally loaded with healthy fats, which can reduce inflammation and may help your body fight cancer. It’s also rich in vitamin E, an antioxidant that can reduce the risk for strokes, help prevent heart disease, type II diabetes and Alzheimer’s.”

Dr Rose says the same cannot be said for other cooking oils, explaining that emerging research shows refined sunflower or soy oils may cause inflammation, increase the risk of obesity, and perhaps even dementia. “Most highly processed and fast foods use these oils, one of the reasons they may damage our health. Potato crisps are a prime example,” says Dr Rose, who believes it’s worth paying the extra for EVOO because the health benefits are so great.

What about frying with olive oil?
It’s a myth that you should not fry with olive oil. Older studies that tested refined or mixed oils at very high temperatures for hours on end may be at the root of this, but recent research has shown that extra virgin olive oil is highly stable when heated.

The presumption that heat destroys the health benefits of extra virgin olive oil has also proved incorrect. Studies show those healthy polyphenols remain intact even at over 200°C.

As research director of the Olive Centre at the University of California, Professor Selina Wang, explains: “They protect the oil from breaking down at high temperatures. Vegetables cooked in olive oil have been shown to be higher in antioxidants because polyphenols were transferred from the oil into the food.”

What olive oil should I buy?
Bob Kubishley of Belazu Ingredients believes “there’s a perfect olive oil out there for everybody. It’s about experimenting. Play around until you find what you like, and ideally buy a couple of different oils — one for frying and one for finishing.”

For everyday cooking, I buy a mid-priced Italian EVOO in a three-litre can and use it in anything from soup to shakshuka.

In drizzles or dressings, where I want a more complex, delicate flavour, my favourite is a supermarket “best” own brand, unfiltered Spanish oil. It’s tangy and flavourful, not too peppery or bitter.

For desserts such as my olive oil cake and ice cream (see facing page) where oil is star of the show, I recommend using a Spanish or Israeli EVOO from arbequina olives — delicate, fruity, with an almost buttery taste.

However, as these olives yield relatively little oil it can be expensive and harder to find — so you can also look for Spanish extra virgin oils labelled “mild and fruity.”.
When you buy EVOO, look for 100 per cent extra virgin olive oil.”

It should also say, “extracted by solely mechanical means”, meaning no solvents or heat were used during processing, with a use-by date no less than a year away, and for more expensive oils, buy in a dark bottle because olive oil degrades with light.

With what we now know about the health benefits of oil and debunking of the myth not to fry with it, it’s becoming increasingly popular in Israel to cook latkes in olive oil. I tried it myself the other day — delicious.