I’ve always kinda known that heating up olive oil would destroy some of its nutritional value, but never really understood what and why. Also, there was always an issue regarding which oils to use for cooking because of a high smoke point and which not to fry or cook with. And so, it seemed like a good idea to (lightly) research the topi c and share my earth-shattering findings with you.
As it turns out, there are three main criteria for chosing your oil; flavour, smoking point and nutritional value.
Flavor, being highly subjective, is probably the easiest to tackle. For me, the king of oils will always be extra virgin olive oil. It’s freshness is almost unmatched by any other oil I’ve tasted. Sesame seed and peanut oil certainly taste great, but lack the finesse and subtlety of olive oil. I understand that avocado oil is now very popular in modern US cuisine, sadly I’ve never tasted it, but I imagine it would be a worthy contender to olive oil. Grapeseed oil is another tasty oil, however, it is quite pricey and again distinctive in taste, and so, you’ll either like it or you won’t. Mind you, the difference between virgin and extra virgin olive oil is related to the purity and acidity of the oil, however, this difference is generally lost when the oil is cooked, and so, no need to splurge on extra virgin olive oil if you’ll be using it for cooking.
There may be times when you look for an oil without any flavor, in which case use sunflower or corn oil.
Smoking point is the temperature at which the oil begins to smoke and burn. When an oil burns it imparts a bitter burnt flavor to the food and so should be avoided. The higher the smoking point the hotter you can the use the oil while cooking, so frying should be reserved for oils with a higher smoking point. Incidentally, avocado oil, which is meant to taste great, has a really high smoking point, which is rare since usually tasty oils have a low smoking point. Oils with a high smoking point (other than avocado) are Sunflower, Sesame, Peanut and Corn.
Nutritional Value with oils generally relates to the presence of omega 3 and 6 acids in the oils, and whether the fats are saturated or not. Generally, olive oil and avocado oil are meant to be the healthiest, however, heating the fats saturates them and makes them less healthy, and so, olive oil loses much of its nutritional value when cooked. Oils high in omega 6 are grapeseed and corn, while those rich in omega 3 are walnut oil and grapeseed oil.