How to Test Olive Oil

Co-authored by wikiHow Staff

Last Updated: May 24, 2021 References

If you’re unsure whether a certain brand of olive oil really is pure, there are a few ways of figuring it out. Unfortunately, lots of brands of olive oil are often tempered with. It's common to find olive oils that are diluted with lighter, cheaper oils. ^{[1]
X
Research source} Luckily, there are ways of testing the purity of olive oil that are actually much simpler than you'd think.

Method 1

Method 1 of 2:

Conducting the Fridge Test

1
Pour 2 to 4 tablespoons of olive oil in a glass jar. Make sure you’re using a very clean jar, as you won’t want anything to mess with the test. Then go ahead and seal the jar shut.
2
Put the jar in your fridge for 24 hours. This gives the olive oil enough time to solidify. You'll want to leave your olive oil as uninterrupted as possible, so avoid moving it around by placing it in a back corner of your fridge.

Advertisement
3
Check to see if the oil is solid or liquid. After the 24 hours has passed, you should be able to tell which state the olive oil is in. At this point you can take it out of the fridge.
- If the oil turned into a solid, it's pure olive oil. This means its monounsaturated (containing only one carbon bond).^{[2]
  X
  Research source}
- If the oil has remained as a liquid, it's not pure olive oil. That would mean that it’s polyunsaturated (containing several carbon bonds).^{[3]
  X
  Research source}

Method 2

Method 2 of 2:

Trying the Oil Lamp Test

1
Coat a wick in olive oil. Olive oil should be able to keep a wick lit if it is indeed extra-virgin. A pure olive oil should also burn smokeless.^{[4]
X
Research source}
- You may want to do this outside in anticipation of possible smoke.
2
Put the wick in a glass container. This test is better and safer when done in a container rather than holding the wick in your hand. The more shallow the container is the better you’ll be able to light the wick.^{[5]
X
Research source}
- Use flame retardant gloves as well. Take care not to burn yourself.
3
Light the wick on fire. If the wick doesn’t remain on fire then you'll know that you're using fake olive oil. If the wick is lit but it’s also producing smoke, you can assume that it's fake olive oil.^{[6]
X
Research source}