Check the purity of mustard oil is a very difficult task without any lab test. Still, you can try below is the list of methods you can try at home safely.

This freezing test is one of the easy ways to check purity of mustard oil. For the freezing test take out a little amount of mustard oil in a bowl.

Then keep the bowl in the fridge for hours. After some time if the oil is freezing and has white spots.

It will remain liquid and clear then you can conclude your mustard oil has adulteration in it otherwise if it will solidify and become cloudy then you can conclude your oil is pure.

Here are the other effective methods to check purity of mustard oil by sniffing test. For the sniffing test take out a little amount of mustard oil in your palms and rub it thoroughly.

After sometimes if it generates a bad chemical odour and also leaves an adulteration colour on the palm then you can safely conclude your mustard oil is not pure.

According to MyGovIndia this nitric acid test is one of the quickest ways to check purity of mustard oil at home.

To perform this nitric acid test in a test tube first pour 2 tablespoons of oil then mix it with 5 ml of nitric acid.

Now shake the mixture well if adulteration is mixed with mustard oil you can see mustard oil starts changing it's colour from rich golden to orange or red or yellow depending upon the amount of adulteration mixed.

If the colour changes then it indicates the presence of a toxic polycyclic salt called Sanguinarine in argemone oil.

This reaction is very sensitive and the colour changes due to the formation of Sanguinarine nitrate. This indicates that the mustard oil is impure.

Here is another method to check purity of mustard oil by smoke point test. 

We all know mustard oil has a high smoke point of about 200 degrees Celsius.

This means it can be heated to a high temperature without smoking or burning.

If the oil starts smoking or crackling at a lower temperature, then you can conclude that your oil is impure. You can also conclude it is a lower-quality oil with it.

You can also check the purity of mustard oil by water test at home.

For this test mix a small amount of mustard oil with water in a glass. If it is pure mustard oil, then it will separate from the water and float on the top then forming a layer of oil.

If the mustard oil does not separate from the water but mixes with water, then you can say your mustard oil is impure.

By doing the above tests to check purity of mustard oil you can identify impurities in your mustard oil.