- Oils are everywhere.

And when it comes to home cooking not all oils are created equal and it can be overwhelming.

(paper crumpling) I'm Sheril Kirshenbaum.

And on this episode of Serving up Science, we're going to explore the varieties of oil and offer some solutions to this cooking conundrum.

(paper crumpling) (cymbal clanking) Let's start with the basics.

Simply put oils are lipids or fats that are liquid at room temperature.

They serve a number of important roles in our body.

Most notably providing long lasting energy.

In the US not so healthy options like vegetable and corn oil are the most widely used in packaged food and fast food restaurants.

Most Americans don't realize they're eating three or more tablespoons of these oils per day.

In chips, crackers, salad dressings, granolas, sauces, cereal, veggie burgers, pretty much any packaged food in your pantry.

- [Customer] Why's all that oil on there?

- Vegetable and corn oils contain polyunsaturated fats and oxidize quickly when heated.

Which isn't good for the body.

Specifically, oxidation is a chemical process that creates free radicals causing damage to cells, proteins, and DNA, which can lead to diseases.

Like cancer, Alzheimer's, Parkinson's and more.

Olive oil is rich in monounsaturated and saturated, fatty acids.

Which are fairly stable when heated, meaning they don't oxidize as quickly.

Fun fact, we need to change our motor oil every few thousand miles because of oxidation.

(drill motor running) When it comes to what we do in the kitchen, oil helps to heat and brown food while adding flavor.

So what to use when?

It's all about temperature and taste and we'll get there, but not before we talk about smoke points.

An oil smoke point is the temperature at which macro-molecules in the oil start to break down, releasing those harmful free radicals we just discussed.

While some cooking shows tell viewers to get their oil smoking hot, it's not actually good advice.

- Smoking.

(buzzer sounding) - At the point, we see smoke rising, the triglyceride molecules break apart, creating free fatty acids and glycerol.

The glycerol further breaks down to water and acrolein.

Acrolein is a mucus membrane irritant.

It can sting our eyes and make us cough.

- (coughing) Sorry.

- There's a lot of smoke.

- When we hit an oil smoke point, we see and smell the smoke and the oil begins to scorch whatever's being cooked.

So when you're ready to saute or sear, what's the best oil to use?

That's where science and your taste buds can help.

Different cooking oils have different smoke points based on their composition.

Cooking at high heat for say, roasting, broiling, grilling or pan frying works best with an oil that has a high smoke point.

Lower heat means more options.

You might choose a less refined oil, but flavor should really drive your decision over smoke point.

As for storage, oils can get rancid over time.

Due to exposure to oxygen, heat, and light.

One reason bottles tend to be tinted is to slow oxidation.

Today, cooking oils are wildly popular, all around the world and easy to take for granted.

But climate change has added pressure to the crops we depend on to produce them.

Historic droughts and higher than normal temperatures are already reducing access and availability of canola and soybean oils from South America to Canada.

Even global conflicts like the war in Ukraine, reduced agricultural exports of once abundant options, like sunflower oil.

That last one's not a climate issue you say, Not directly, but as the resources we depend on around the world become ever scarcer, it can impact the global food supply chain.

Meaning the oils we love may be harder to come by.

You see in the big picture, everything is connected.

The agricultural practices that sustain us, depend on countless people and natural systems that interact in ways we never even see to provide the foods and oils we enjoy daily.

(upbeat music)