A closer look at cooking oil: five facts about the cook’s best friend

From food truck to 5-star cuisine, cooking oil is used in every kitchen. But how is it actually made? What should chefs consider when buying it and how should they dispose of it?


An extruding press sounds painful...

No, there’s no pain involved – even if the name ‘extruding press’ does sound like something out of a torture chamber. It’s actually a machine for extracting oil. Seeds are placed in a horizontal housing with a helical shaft. The twisting and pressure creates heat that presses out the liquid oil, which runs through a filter into a collecting pan. And the oil is ready!

Caution, fine: oil disposal can be expensive

Oil on troubled waters? Maybe not... If oil residue ends up down the drain, it can bond with fabric scraps and nappies to form enormous clumps that block up sewers. For this reason, many municipalities offer sealable polyethylene containers for collecting cooking fats and fryer oil waste. But beware: incorrect disposal is an offence that can incur a fine.

Olive oil - a slippery fraud

Look out if the label says ‘extra virgin’ olive oil! Olive oil is one of the most commonly faked foods. Often, bottles contain blends of a wide range of olive oils – or even other plant oils. But identifying fraudulent labelling is difficult. A good indication of genuine olive oil is the standalone description ‘100% extra virgin olive oil’. Also, the production location should be in Europe – for example in Croatia, where olives are native and oils are sometimes manufactured by family businesses like the Fernetichs.


A few examples of cooking oil smoke points: 

Sunflower oil: 107 °C
Butter: 177 °C
Extra virgin olive oil: 191 °C
Virgin olive oil: 216 °C
Refined rapeseed oil: 240 °C

Flavour is everything

Oil doesn’t keep forever. But how do you find out if a bottle is still good? It’s all in the flavour. A fusty-musty, sometimes scorched flavour combined with a rancid smell indicates that oil is no longer suitable for use. A bitter or sharp flavour isn’t too much of a problem; the earlier the olives were harvested, the sharper the taste of the oil. Otherwise, a good rule of thumb is that unopened refined oils keep for up to two years. Delicate oils like linseed oil keep for a much shorter time – once open, just a few weeks. To keep oils enjoyable for as long as possible, they should be stored in a cool, dark place.

Watch out for the smoke point

Every restaurateur should have heard of the smoke point, and it should never be exceeded. It is the temperature at which oil starts to burn. This impairs the flavour drastically and can ruin the entire dish. It’s vital to know your own hob and be able to estimate the heat generation, whether it’s gas or induction.

The quality oils offered by METRO are responsibly sourced and sustainable, and meet the needs of every professional. Find out more here: responsibility.metroag.de

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