Why is there a difference?

The color difference is present not only between different fuels, but also between the same fuel, and is related to the composition and production processes of the fuel. When gasoline freshly leaves the refineries, called type A gasoline, it should have a transparent or slightly yellowish color. At this stage, the gasoline has not yet been mixed with anhydrous ethyl alcohol (which should correspond to 25% of the mixture, in order to reduce the emission of polluting gases), and the gasoline is still in its purest state. After mixing, it is normal for the color to become slightly more yellowish, due to the mixture of the compounds.

However, the regular gasoline sold does not have a large color variation when compared to other types of gasoline or even fuels, such as additive gasoline and diesel, for example. The biggest difference, compared to other types of gasoline, is mainly due to the detergents and additives present in the composition of the others. Read more about detergents and additives by clicking here. But it is also necessary to know that some types of gasoline have the addition of dyes for differentiation, some simpler and others more different, as is the case of Shell V-Power gasoline, which is green in color. In addition, it is possible to observe (slight) variations in gasoline brands, and certainly greater variations in other fuels, mainly due to their different compounds.

The different colors of gasoline
Regular gasoline:

This is the most widely sold type of gasoline, and is generally colorless or slightly yellowish. This specification is defined by the National Petroleum Agency (ANP), since the refining processes and chemical composition of the fuel guarantee the variation.

Premium gasoline:

Despite being a superior gasoline to regular gasoline, which is defined due to its higher octane level (learn more by clicking here), the color of Premium gasoline is the same as regular gasoline, and varies between transparent and slightly yellowish.

This color is also defined by the ANP, and the equality remains due to the composition, which is very similar, including the amount of anhydrous alcohol present in the mixture (25%).

Additive gasoline:

Additive gasoline generally contains dyes in its composition, which differentiate the compound from regular gasoline. These dyes can be decided by the producer with one exception: the color cannot be blue or pink. This is because the color blue is intended for aviation fuels and pink is used in more restricted situations.

Therefore, most producers define the color green as representing their additive gasoline. It is important to know that the color of the gasoline does not change the performance of the vehicle’s engine in any way, and that the color itself does not have a positive or negative impact, but rather the compounds in the gasoline, which in the case of additive gasoline promise improvements in relation to regular gasoline.

Aviation gasoline:

Also known by its acronym GAV, aviation gasoline is a completely different fuel from gasoline used in cars and motorcycles. This type of fuel has a bluish color, exclusive to this type, and all of its characteristics are controlled by rigorous tests before it is actually used.

Color of other fuels and how to tell them apart

In addition to the difference between the colors of gasoline, it is also interesting to know about the color difference between other fuels. The most difficult difference to notice is between regular gasoline and alcohol (regular ethanol), precisely because regular gasoline, if not slightly yellowish, should be transparent. In this case, the difference can be better perceived from the smell of the fuel, since ethanol has a smell much closer to 70% alcohol than gasoline. (Attention: The strong smells of gasoline and ethanol can be harmful to health; we recommend that, if necessary, the smell be smelled from a distance).

In the case of Diesel Oil, the difference is much easier to notice, since it is a fuel that has greater differences from gasoline. Both S10 and S500 diesel have darker colors than gasoline. While S10 can vary in color between dark yellow, orange and brown, S500 must be red due to resolution No. 65, of 2011, of the ANP (National Petroleum Agency). Article 11 of the resolution specifies the color red precisely so that S500 cannot be confused with S10, given the previous occurrence of episodes like this. In addition, Diesel Oil has a much higher density than gasoline, and resembles the consistency of cooking oil. Read more about S10 Diesel Oil by clicking here, and about S500 Diesel here! Therefore, if it is not possible to identify the difference by color, the consistency of the fluid will certainly distinguish it from gasoline.

Test on the spot

Any customer who suspects the quality of gasoline, whether due to its color or any other reason, has the right to request a test on the spot of the fuel. This test, called the purity test, also known as the “test tube test”, must be requested from the gas station attendant, and is guaranteed by law by ANP resolution no. 9, of 2007. The resolution requires the gas station to perform the test whenever requested by any customer.

If the establishment refuses to perform the test, the customer must file a complaint directly with the ANP, so that the appropriate measures can be taken.

The test basically consists of mixing 50% gasoline with 50% of a mixture of water and table salt. After 15 minutes, the separation of the liquids becomes visible to the naked eye, with the ethanol being transferred to the water and the gasoline separated in the upper part of the test tube.

If the separation does not occur properly, it is a strong indication that the fuel is adulterated.