From Jules Clancy via “Stone Soup”
How do I know if an oil is stable?
The best indicator is to look at the ‘smoke point’ of the oil. This is just a measure of the temperature at which a given oil starts to give off smoke.
Yep. It’s that simple.
As a rule, the more pure an oil is and the less polyunsaturated fatty acids it contains (ie. the more saturated it is), the more stable it will be. So the higher the ‘smoke point’ temperature, the more stable your oil.
Why should I care about oil ‘stability’?
Unstable oils chemically change their composition when exposed to heat (and light). They break down and release some toxic substances including ‘free radicals’.
Free radicals aren’t your friends.
They cause damage to our cell membranes, our blood vessels and even our DNA (genetic material). As you can imagine, this isn’t great. The damage leads to things like premature aging, immune problems and even cancer. Got your attention now?
My favourite fats and oils
- Rice Bran Oil. These days, rice bran oil is my ‘go to’ oil for cooking. It has a relatively high smoke point, so it’s pretty stable. It’s also much less expensive than olive oil. As an added bonus it’s mostly mono-unsaturated and contains Vitamin E and some antioxidants (which combat free radicals!). So it has good health credentials.The flavour is bland and neutral so it’s also great for making mayonnaise or for Asian cooking. Anywhere you don’t want the oil flavour to intrude. If rice bran oil isn’t available where you live, my previous favourite cooking oil was peanut oil. You can get ‘cold pressed’ peanut oil which tastes like, errh peanuts. The oil I was using was commercially ‘deodourised’. It had a neutral flavour and didn’t make everything taste like PNB.
- Extra Virgin Olive Oil. You’re probably aware that extra virgin olive oil tastes delicious and is high in mono-unsaturated fatty acids, so healthy as well. It’s my go to oil for salad dressings and drizzling on things like soups and stews just before serving for extra richness and flavor.Unfortunately olive oil doesn’t have a super high smoke point. Which means it isn’t a great choice for cooking at high temperatures. I’ve also conducted an experiment and found that the delicate flavours of expensive extra virgin olive oil are lost during the cooking process. So it’s a bit of a waste of money to cook with your best EVOO.
If you are planning to roast or pan fry with olive oil, it is best to use refined ‘extra light’ olive oil which has a higher smoke point than virgin oils.
- Butter. When it comes to flavour butter wins! While the fat component is stable with high saturated and mono-unsaturated fatty acids, the milk proteins cause browning and smoking.I use it for the frying pan when flavour is important and the heat won’t be too high. Things like scrambled eggs, omelets, pancakes, softening onions or mushrooms (see recipe below).
But if I’m planning to use butter for high temperature cooking like pan frying or roasting, I ‘clarify’ it to remove the proteins. It’s much less scary than it sounds. All you do is melt the butter in a small saucepan and pour the clear butter oil off the top, discarding the white solids (protein and water) below. Butter is also surprisingly healthy (more details over here).
- Other I use sesame oil for flavour in Asian dishes. I always add it at the end because, you guessed it, it doesn’t have a high smoke point. I sometimes buy a can of duck fat for roasting potatoes. Duck fat adds the most amazing flavour. It’s saturated so you don’t need worry about the stability in the oven. But not so easy on the wallet!I buy coconut oil from time to time to use in baking. Generally I prefer the flavor of butter but if I did ever need to be dairy-free I’d reach for coconut oil.