By Harriet Mallinson | Published on June 26, 2017
Olive oil is a staple of most kitchens, whether you’re cooking with it or dipping a hunk of fresh bread in a bowl of the stuff.
However, a lot of chemistry goes on in that bottle that can make or break a product, from the moment the olives are picked right up until your pour the last drop into your Bolognese sauce.
A fascinating video produced by the American Chemical Society explains all about olive oil chemistry, including how to keep yours fresh and how to best use it to give your food a flavor boost.
Olive trees thrive in the sunny climate of the Mediterranean, with olive oil considered one of the core elements of the hugely popular Mediterranean diet. Unsurprisingly, it’s the olives with higher oil content that are favored by farmers while olives harvested at different points in the season produce different flavors.
Once picked, the olives are crushed, along with the the pips, into a paste and then churned. The oil is then separated from the pulp and water – most commonly by a centrifuge.
Incredibly it takes 1000 litres of olive to make high quality olive oil. Lower quality oil use chemical solvents like hexane that help to pull every last bit of oil out of the paste, but superior oils do not use this method.
To meet the required standards of extra virgin olive oil – the most expensive and the most flavorful olive oil – there have to be no flavor defects caused by fermentation or oxidation.
When it comes to cooking, olive oil is a healthier alternative to refined vegetable oils as it’s rich in monounsaturated fatty acids that serve to increase the rate at which cells pull bad cholesterol out of the blood stream.
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Olive oil is loaded with antioxidants in the form of plant phenols and vitamin E which the body uses to keep free radicals in check which might otherwise cause cell damage. Amazingly, these antioxidants can actually be tasted in olive oil’s peppery notes.
At high temperatures the nutritional content can start to degrade but extra virgin olive oil can safely be used for frying, sautéing and baking (up to 400ºF) – any higher and you should use refined olive oil or vegetable oil.
Extra virgin olive oil is at its best in cold dishes or food where you want its complex flavor to come through.
A really good oil should be reminiscent of the olive grove it initially came from, so should have a grassy or a fruity flavor. An inferior oil is more likely to taste of something stored in your garage for a long time.
Focus on freshness when choosing oil rather than how expensive it is as olive oil does not age well – light and heat are the natural enemies of the oil and it can start to taste rancid over time as the fatty acids break down. The antioxidant content will decline too.
So, protect your oil from heat, light and air to help preserve it as long as possible, but try and use it up in six weeks or so to keep oxidation at a minimum. It’s also worth checking the harvest date on the bottle to ensure you’re getting the freshest stuff.
Harriet is Editor of MACROS and perfectly capable of eating an entire log of goat’s cheese in one sitting.