Most additive companies are blenders rather than manufacturers. Chemicals are purchased from a variety of chemical manufacturers and are then blended with a carrying oil of some sort to package the product in a marketable form. Chemicals that go into the blending oil are known in the industry as ‘active ingredients’.

Herein lies the answer to most questions about additive quality: low grade products have very little active ingredients and often consist of around 90% carrying oil. The color test can often tell you a lot about the content of active ingredients in an additive.

Generally, additives containing pour point improvers or detergents with more active ingredients will be darker in colour.