We’ve all heard the advice about cooking with extra virgin olive oil. It’s a healthy oil with a low smoke point. And we all know that oils—even good oils—corrupt when they hit their smoke point, lose their healthful properties, and can even become dangerous to our bodies.
But what exactly is the science behind this advice? What happens to oil when it hits its smoke point? How bad is it, really? And what is a smoke point in terms of ye olde average cooking experience in your home?
Let’s talk chemistry.
Wait…come back! Don’t leave now, it’s just getting interesting! We’ll keep it short.
When oils heat up to their smoke point, it means that the oil is starting to break down chemically from its room temperature form. When food oils break down over heat, they produce a chemical compound called acrolein, which is a member of the aldehyde family. Acrolein is where burned food gets much of its bitter smell and taste.
Acrolein is used industrially as a contact herbicide to inhibit the growth of algae in irrigation canals and water cooling towers, and in drilling water for the oil industry. Sounds delicious, doesn’t it?
In the human body, acrolein is a strong irritant for delicate mucous membranes (eyes, nose, throat, lungs, etc). It is toxic to living cells, causes inflammation, and in animal studies, causes benign tumors on the adrenal glands and lesions on the lungs, spleen, and thyroids of the test subjects.
That Sounds Terrible!
It does, doesn’t it? But the problem isn’t nearly as awful as it sounds from the chemical analysis. Here’s why:
- Acrolein is everywhere. It is a natural product of the fermentation/ripening process, and of incomplete combustion (car exhaust, wood smoke, heating fuel, etc.). It is in our air, our soil, our water, and our bodies.
- Our bodies are used to processing acrolein. It breaks down and is flushed out of our system through the kidneys and bladder.
- Yes, all those sickening problems did happen to research animals who were exposed to acrolein, but they were exposed to massive levels of it. Far beyond what humans typically experience.
- The group of average humans who are exposed to the highest levels of acrolein are smokers. Cigarettes produce about the same amount of acrolein as all other daily sources combined.
How Does All that Apply to Cooking Oil?
First and foremost let’s talk about oil temperatures. After all, acrolein isn’t an issue if you don’t reach your oil’s smoke point.
Extra virgin olive oil smokes at around 374⁰F, and virgin oil smokes at about 410⁰F. Cooktop stoves aren’t uniform in their temperature, of course, but there’s certainly an average range. Medium is around 240⁰ to 270⁰, and medium-high is roughly 300⁰ to 360⁰. Now…at what setting do you usually do your sautéing? See? No worries.
Secondly, we all know that eventually, our cooking oil will smoke. It won’t be on purpose, but it will happen. Following the study referenced above, the WHO made recommendations on how much acrolein a human body can safely process. When you compare those recommended limits to how much acrolein the average cooking oils produce, a simple choice of oils fixes most of the problem.
Corn and sunflower oils produce the highest amounts of acrolein (20 times higher than the WHO recommended safe amounts!), while extra virgin olive oil is much safer.
What’s the moral of today’s blog? Know your stove, know your cooking oils, and listen in science class. We here at Old Town Olive want you to be able to enjoy our olive oils from a fully educated point of view. Come in and see us. Taste the oils and ask any question you can think of before you buy.