Guide
Which cooking oil belongs in the refrigerator – and which doesn’t?
by Anna Sandner
Don’t use olive oil for frying: true or false?
7/3/2025
Translation: Megan Cornish
Olive oil has been considered one of the most valuable vegetable oils for thousands of years. The secret? A unique combination of fatty acids, antioxidants and vitamins. But not all olive oil is equally good for your health.
Olive oil’s an indispensable part of Mediterranean cuisine. And the Mediterranean diet’s not considered one of the world’s healthiest diets for nothing. While we like to use olive oil to refine our dishes here, in countries including Spain and Italy, it’s practically the base ingredient used to downright drown vegetables, meat and fish. And rightly so – if you look into its health-promoting properties.
Should you heat olive oil?
Before looking at the health benefits of olive oil, let’s look at whether you should use it for frying or not. It’s a myth that you should never heat olive oil. There are differences depending on how it’s processed, but in general you can use clear olive oil for frying or deep-frying.
However, you shouldn’t heat it above its smoking point. This is where volatile components such as water or free fatty acids evaporate and form visible smoke. Generally speaking, the less processed an oil is, the lower its smoking point. For cold-pressed oils, it’s between 120 and 190 degrees; for more processed (refined) oils, it’s over 200 degrees.
So, you shouldn’t use naturally cloudy olive oil for frying or deep-frying. The residual water and small pieces of pulp it contains mean it reaches its smoking point more quickly.
Heating olive oil moderately retains the bulk of its health-promoting properties. Alternatively, you can simply fry your food in a more heat-resistant oil (e.g. rapeseed oil) and then refine it with high-quality olive oil when serving.
One of the largest studies on the Mediterranean diet shows that four tablespoons of extra virgin olive oil a day reduces the risk of cardiovascular disease by 30 per cent. And that’s not all: it can also improve insulin sensitivity, reducing the risk of diabetes.
In addition, substances such as oleocanthal in olive oil can cross the blood-brain barrier and slow down nerve-damaging processes. The active ingredients inhibit the accumulation of amyloid-beta plaques, which are associated with Alzheimer’s.
Extra virgin, virgin olive oil, cold pressed – what does it all mean?
In Germany and Switzerland, olive oil is divided into three quality classes that differ in their sensory properties and free fatty acid content. The fewer free fatty acids there are, the fewer bitter substances there are and the higher the quality of the oil.
Extra virgin olive oil is the highest quality, containing a maximum of 0.8 grammes of free fatty acids per 100 grammes.
Grade 5 olive oil is a mixture of hot-pressed (refined) and cold-pressed (virgin) olive oil. It can have an acidity of up to 1.5 per cent.
Header image: Mareefe/Shutterstock
Anna Sandner
Senior Editor
Anna.Sandner@galaxus.deScience editor and biologist. I love animals and am fascinated by plants, their abilities and everything you can do with them. That's why my favourite place is always the outdoors - somewhere in nature, preferably in my wild garden.
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