Does Oil Evaporate When Cooking? (Myth Busters)

Oils are the basis for many recipes and play a major part in different cooking techniques, from sautéing and stir-frying to roasting and baking. If you’re into cooking hot meals, you may be wondering if oil evaporates while cooking.

Here’s a quick answer:

Oil doesn't evaporate while cooking because it contains heavy molecules with long carbon chains. These molecules can only decompose and turn into black smoke. The smoke from your pan isn't oil evaporation. It means the oil is heating aerobically, and the continuation may cause it to burn and catch fire.

Oil doesn’t have a melting and boiling point which makes it more unique. So, let’s find more about its properties.

Why Doesn’t Cooking Oil Evaporate?

Vegetable oils and animal fats have large molecules and carbon chains entangled with each other like spaghetti. Such large molecules cannot “fly away” or evaporate from the liquid surface. When heated, these molecules don’t boil and go off as vapor. Instead, they break into smaller pieces and become oxidized, releasing hot smoke and an unpleasant odor.

If you heat further, the temperature becomes high enough for the decomposed material to smoke and catch fire.

If you want to burn or destroy the oil, keep it heating continuously. The smoke will continue to produce, and the molecules will keep on breaking. And eventually, the oil will become an unpleasant and unusable substance.

Selecting the Right Cooking Oil – Kitchen Conundrums with Thomas Joseph

Why Does the Chimney Get Greasy?

So if oil doesn’t evaporate, then why do the chambers of chimneys get a greasy layer? The chimney may get a greasy film because:

  1. The particles in the smoke from burning cooking oil can feel somewhat greasy
  2. When cooking oil breaks down under heat, some of the new molecules can be light enough to become airborne and build a greasy film.
  3. When you fry something, the oil droplets may come out of the pan. You can notice them on the stove and around your pan. Some oil droplets are small enough to be carried by the upward draft of hot smoke from the pan and into the chimney.

How to Safely Cook with Oil?

All kinds of oils have their smoke and flash points. So while cooking something in vegetable oil, make sure you oil doesn’t reach its flash point to avoid a total disaster. 

Reaching past the smoke point makes the oil harmful to use.

How to Properly Deep-Fry Food?

Deep frying food is very popular and here’s how you can deep-fry like pro:

  1. Choose an appropriate vegetable oil, one that has a higher smoke or flash point than the desired cooking temperature. Soybean, avacdo oil, and sunflower oils are our favorites for deep-frying at high temperatures. For a list of smoke points of different oils, check out the Modernist Cuisine at Home.
  2. Add the oil to a pot, but fill it no more than half full so that there are no spillovers. This also makes cleanup easier. Use enough oil so that you can cook a small batch of food easily.
  3. Preheat the oil to the desired cooking temperature. Use a thermometer held upright in the center of the pot of oil to check the temperature. Make sure your frying thermometer can display temperatures up to 500 °F. Frying and thermocouple thermometers typically have this much range. For consistent results, cook in smaller batches and warm the food to room temperature before deep-frying it. Allow the oil temperature to recover between different food batches.
  4. Pat your food dry with paper towels before deep-frying. The presence of external moisture can cause oil to splatter violently. Don’t get too close to the hot oil. Use long tongs, a deep-fry spoon, or a frying basket to add and remove foods gently. Never use flour or water to put out a grease fire. And do not try to carry a flaming pot outdoors. To extinguish a fire, use a fire extinguisher specifically designed for kitchen fires.
  5. Things happen fast once food enters the hot oil. Just 60 seconds may be enough when you don’t want to cook the food all the way (for example, when frying food after cooking it sous vide). Smaller food pieces will cook faster and more evenly than larger pieces.
  6. Drain the deep-fried food on paper towels. Absorbing excess oil removes the fat associated with deep-frying. Most of the fat does not penetrate the food and coats only the surface. Simply blotting deep-fried food as soon as you take it out of the fryer will make it less greasy. 
  7. Use saturated and monounsaturated oil. Oils with high saturated and monounsaturated properties are the most suitable for frying. Oils with high polyphenols or antioxidants also work great as they are not damageable at high temperatures. These include rapeseed oil and olive oil.
  8. Use a wide-mouth pan and well-fitting lid. Always use a sturdy, wide, and large pan when you want to fry something. Fill only two-third of the pan with oil. If you fill it near the mouth, the oil may bubble up and spill over when you add food.  Also, make sure you use an appropriate lid that covers the whole pan if the oil catches fire. A flat baking sheet can also do this job of the lid. 
  9. When it’s time to remove the food from the oil, use a large slotted spoon or sturdy tongs. They allow excess oil to drain and keep the food crispy.
  10. Dispose of the oil after frying. After frying, leave the oil to cool so that you can safely dispose of it. Pour the oil into its original bottle once cooled, and don’t dispose of it down the sink to avoid blockage of pipes.   

How to Cook Regular Food with Oil or Grease?

Here are some points to keep in mind when cooking with oil or grease:

  • Heat the oil to the desired temperature: Before cooking, you need to know the oil temperature required for the recipe. So, slowly heat the grease or oil to that temperature.
  • Add food slowly: Once the oil is hot, add the food gently into the pan. Throwing the food or dropping it into hot oil can cause it to dangerously splutter.
  • Use a lid to cover the pan: You should always have a lid present on your kitchen countertop. If the oil splutters due to contact with wet food, covering the pan will help to solve the issue. 
  • Lower the flame in case of smoke: Sometimes, the oil gets too hot and releases smoke and a strong unpleasant burning smell. This indicates that the oil may ignite, so you’ll want to immediately lower the flame. But if the oil catches fire, cover the pan with a lid and turn off the flame. 

What Is the Healthiest All-around Oil?

Olive oil has unlimited health benefits for everyone without breaking down. You can use it for almost everything from cooking rice to frying boneless chicken breasts or a raw dressing to salads. 

The healthiest type of oil is Extra Virgin Olive Oil or EVOO.

Here are some benefits of olive oil:

  • Helps to lose weight: Even though olive oil is high in calories, it helps to reduce obesity. Medical experts also confirm that it’s hard to gain weight from the monounsaturated fats of olive oil. 
  • Reduces heart issue, high blood pressure, & diabetes risks: There is 70% monounsaturated fatty acid in olive oil. These fatty acids prevent cholesterol accumulation in the blood and hence protect from heart problems. 

Olive oil also lowers down the risk of atherosclerosis and diabetes. And regular consumption of this oil helps to decrease both systolic and diastolic blood pressure.

  • Anti-inflammatory: The phenols present in olive oil provide anti-inflammatory properties. These may also act as painkillers and fever reducers. The olive oil phenols help to prevent brain tumors and kill cancer cells in the body. 

There is a phenolic compound “oleocanthal” in extra virgin olive oil. This phenol works efficiently to avoid Alzheimer’s disease.

  • Enhances skin and hair health: Extra virgin olive oil (EVOO) contains rich amounts of Vitamin E, a fat-soluble antioxidant. A single tablespoon of this oil contains about 1.9 mg of Vitamin E. It protects you from eye and skin problems and boosts the growth of your hair. 

The extra virgin olive oil also avoids neurological diseases, diabetes, and lung cancer.

  • Fights depression and mood disorders: Olive oil contains healthy fats along with anti-inflammatory and hormone-balancing effects. These effects reduce the risk of neurotransmitter dysfunction. Whereas, Low-fat foods have higher rates of anxiety and depression. 

When your brain doesn’t get serotonin or dopamine (happy hormones), you experience mood or cognitive disorders. 

Serotonin and dopamine are important chemical messengers that help to regulate mood, sleep better, and think efficiently and actively. 

  • Boosts metabolism: Olive oil enhances the metabolic functions and good bone structure in your body. It assists in the brain growth of children and also provides vitamin E, necessary for older people.


Can cooking oil make you gain weight?

Yes, it makes you gain weight as oil is 100% liquid fat. And high-fat foods are unhealthy. Research shows that oil contains two times more calories than refined sugar.

Is cooking oil unhealthy? 

It may or may not be unhealthy. Oils contain healthy fat sources. However, hydrogenated oils have high levels of unhealthy trans fats. So, avoid it if you’re on a diet. 

What evaporates faster, water or oil?

Different liquids evaporate at different rates according to their physical properties. Nail polish remover evaporates quickly. Then comes water, salt water, vinegar, orange juice, and oil.

Why does water evaporate but not oil?

Oil is denser than water. It contains large molecules having strong intermolecular forces between them. And thus water evaporates more quickly than oil. 

Is vegetable oil better than olive oil?

Extra virgin olive oil is always better and healthier than vegetable oil and vegetable oil blends. It improves cognitive function in young adults less than twenty years old.

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