Environmental Impact of Cooking Oils

What do you know about your cooking oil?

Bottles of Six Plant-Derived Cooking Oils with Seeds, Fruits, and Nuts

Have you ever considered the environmental impact of the cooking oil you routinely buy to stock your pantry? Maybe you should.

Take a moment to picture the cooking oils you have in your home right now. Some of you may have visualized one bottle while others saw a collection of bottles.

The thing is every household in the world probably holds at least one container of cooking oil. It is inconceivable that those hundreds of millions of bottles, jars, and cans of cooking oil do not cause environmental harm. The questions roaming about in my head were how much and does it matter.

I decided to try to find out and share what I learned in this post.

What is Cooking Oil?

Cooking oil is used to transfer heat from a pan to food, keep food from sticking to the pan, and in some cases to impart flavor. Oils do not mix with the water contained in food which is why French fries maintain a crusty exterior as long as you do not cook them long enough to cook all the water out of the potatoes. If you do, your fries will be soft and oily.

Before embarking on this project, I needed to rope in (persuade) my spouse to participate because as the family chef my spouse would be the one cooking with a variety of different oils. I would be fulfilling the role of taste tester and researcher.

At our local grocery market, I selected seven different oils using the totally non-scientific method of picking bottles that I thought would make an attractive photo.

Back at home, I placed the bottles of oil in our pantry and we proceeded to put away the rest of our groceries. When I opened the refrigerator, I was confronted with a covered dish containing half of a stick of butter and a jar of coconut oil. Hmm, were these cooking oils, too?

That led to the question “What constitutes cooking oil?”

I did not find a definitive answer. Generally cooking oil is a fat derived from a plant that is liquid at room temperature such as olive, canola, and peanut oil.

Terrific that seemed straightforward except…

Coconut oil is plant-based oil but it is solid at room temperature. Is it still oil? What about butter? Butter is derived from an animal and is used for cooking, but is solid at room temperature. Oh, and what exactly makes something a fat?

I wanted answers so I approached my son who is a physicist and is skilled at explaining science to non-scientists like me. He gave me the French fries example above.

From my son, I learned about fatty acids, lipids, and glycerol, which you can read about using the links at the left.

One thing that I found fascinating is that edible fat molecules and inedible petroleum molecules are more similar than you might think. They are both slippery meaning good at lubricating stuff. However, edible fat molecules also have a molecular handle that allows other molecules in your body to grab onto them to run your biological machinery and keep you healthy.

Model of a Triglyceride (Fat) Molecule

This is a molecular model of a fat or triglyceride. Note the three fatty acid chains attached to the central glycerol (red) portion of the molecule. Image – Wikipedia.

To summarize cooking oils are fats that your body needs to function. These fats come from plants, animals, and are sometimes synthesized in laboratories. Cooking oils are generally liquid at room temperature but not always.

Growing Oil Crops

In this post, we are discussing plant-based cooking oils that are derived from tree fruits (e.g., avocado and olive), nuts (e.g., walnut and peanut), and seeds (e.g., canola [rapeseed] and sunflower).

Oil crops can be grown in harmony with nature intermixing with other plants and animals and growing up without synthetic fertilizers or pesticides. Cooking oils that meet certain environmental standards and are certified by an independent third party can be marketed as USDA organic.

On industrial-scale farms, trees and plants are often grown as monocrops which is the practice of growing a single crop on the same section of land year after year. This type of agriculture kills the soil so synthetic fertilizers must be applied to provide nutrients for the plants. In addition, monocrops are susceptible to being wiped out by insect pests and taken over by plant pests (weeds) so massive amounts of pesticides are used in an attempt to prevent these problems.

Blooming Canola Field in Saskatchewan, Canada with Storm Clouds
This is an industrial-scale monocrop canola field in Saskatchewan, Canada – photo credit Nas2/Wikipedia.

To combat the monocrop pest problem some growers use GMO (genetically modified organism) seeds that have been genetically engineered to withstand the application of ever more powerful pesticides. Nowadays, in the U.S., most soybeans and canola plants are grown from GMO seeds.

Oil trees and crops grow in a variety of climates and some are thirstier than others.

Problems for people and other members of nature arise when huge swaths of land are cleared to make way for monocrop tree plantations and agricultural fields. The repercussions are significant and cumulative meaning they get worse over time. Habitat loss, soil erosion, sedimentation in streams, air and water pollution, and the destruction of biodiversity endanger the health of ecosystems all over the world that support life on Earth.

Of course, the environmental damage caused by growing monocrops on an industrial scale is universal and not just confined to oil crops.

Making Cooking Oil

Peanuts in Shells in a Bag

Plant-derived oils are made by squeezing the oil out of the flesh of fruits like avocados and olives, from nuts such as peanuts and almonds, and from seeds like sesame and safflower. Photo credit – American Peanut Council.

Some oils are then refined, bleached, and deodorized to change their color and to remove the flavor of the source plant. Extraction and processing methods affect the look, taste, and sales price of cooking oils.

Cold-Press – in this process, the fruit is ground into a paste and then pressed through a series of disks using hydraulic pressure without producing heat. Sometimes the paste is pressed multiple times to extract every last bit of oil. Extra virgin olive oil is produced from the first press.

Expeller Pressing Machine

Expeller Press – is a machine used to extract oil from nuts and seeds by squeezing them under continuous high pressure. The friction created by this process heats the oil which may affect the nutrient content and taste of the oil. Photo credit – Matthewsr2000/Wikipedia.

Decanter Centrifuge – uses high rotational speed to separate fruit, nut, and seed pulp from the oil contained within them. Edible oils like olive oil may use a 3-phase separation process that makes it possible to separate the oil, water, and solids in one step.

Solvent Extraction – involves using a substance that can dissolve other substances to extract oil from oil crops. Hexane is a highly flammable chemical made from crude oil that is used as a solvent to extract vegetable oils from crops such as soybeans and canola.

Cooking Oil Tests

Seven Cooking Oils for Testing
These are the oils we used for our cooking oil tests (left to right) – sunflower, olive, hemp, canola, safflower, grapeseed, and avocad0.

Over a period of several months, our family taste-tested six of the seven cooking oils I had selected at the grocery market. Some oils like olive oil imparted more flavor than others such as sunflower oil but none of the oils interfered with the deliciousness of any of the dishes my spouse prepared using them.

The hemp oil is still sitting in the cupboard unopened. That is because when I actually read the label I discovered that its low smoke point makes it unsuitable for cooking. We do not make a lot of salad dressings or often sprinkle oil on food so we have not had a reason to try the hemp oil.

What is the Most Eco-Friendly Cooking Oil?

After reading dozens of articles and blog posts and a couple of research reports, I had learned about cooking with various oils, land use issues, oil extraction methods, GMO seeds, unintended consequences, different types of fat, and fake olive oil.

It was time to go back to the questions that I had been attempting to answer. What is the environmental impact of cooking oil? Does it matter?

You guessed it. The answer to the first question is it depends. Small-scale farms using organic and/or regenerative agriculture practices probably create significantly less harm than huge monocrop operations that gobble up forests and encourage the proliferation of pesticide use.

Other factors to consider are the amount of water, land, and energy required to grow and process the oil. The source of the energy affects the carbon footprint of the oil (e.g., coal versus sun).

The number of miles your cooking oil travels from the field to the processing facility to the store to your home is important, too. For instance, consider a bottle of artisanal olive oil sitting on a California grocery market shelf that was produced by a small organic outfit in Spain. The product itself may be eco-friendly but the fact that it has traveled thousands of miles to get to your pantry is not.

That brings us to the other question. Does the environmental impact of cooking oil matter?

Well, there are many things that are much worse like fracking for natural gas or raising livestock animals for meat. It would be easy to say that the environmental footprint of cooking oils is not something to be concerned about. However, the sheer volume of something small like cooking oil when taken collectively can indeed make a significant impact so it is probably worth at least a little consideration.

Which Cooking Oil is Right for You?

As it turned out, for our family, the most eco-friendly cooking oil we can buy is the organic extra virgin olive oil we purchase by the gallon at our local farmers market from Mt. Olive Organic Farm. There are so many reasons this is a good choice for us.

Mt. Olive Organic Farm Booth at Farmers Market in Cambria, CA on February 7, 2020
Kaylee and James at the Mt. Olive Organic Farm booth during the farmers market in Cambria, CA on February 7, 2020.

The Mediterranean climate in our region is good for growing olive trees. Mt. Olive Organic Farm uses organic farming and processing practices. The olive oil travels less than 35 miles between the farm and the farmers market which is about a quarter of a mile from our house. At home, we pour the olive oil from the one-gallon jug into a smaller bottle and put it in our cupboard. When the original bottle is empty we return it, buy a new bottle, and the old bottle gets reused.

Equally important to us is that by buying this and other locally grown and made products we are supporting the livelihoods of the people who live here not in some distant place hundreds or thousands of miles away. Plus we have the opportunity to meet and talk with the people who are growing our food.

We keep organic canola oil and sesame oil on hand, too.

There are so many different plants that can be used to make cooking oil it seems likely that locally grown and produced oil is probably available to almost anyone. You just have to look for it.

Now, I hope you feel at least a little informed about the environmental impact of cooking oil. Please take a few minutes to consider your own cooking oil choices and decide whether you want to try something new.

Featured Image at Top

These bottles of six different plant-derived cooking oils are shown with their corresponding seed, fruit, or nut – photo credit iStock/AlexPro9500.

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Author: Linda Poppenheimer

Linda researches and writes about environmental topics to share information and to spark conversation. Her mission is to live more lightly on Earth and to persuade everyone else to do the same.

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