Super-grade is just a propaganda tool for merchants. The national standards for edible linseed oil are Grade I, Grade II, Grade III and Grade IV, and Grade IV is crude oil, which is just squeezed out. There are many impurities, but the taste is also the strongest. However, in order to meet the edible standard of linseed oil, refining (deodorization, decoloration, dewaxing, degumming, etc.) is necessary. "The higher the refining degree, the better the nutritional value is not necessarily." This sentence is correct, because in the refining process, some impurities will be removed, but some nutrients in the oil will also be removed. The national standard for measuring the grade of linseed oil is based on the test results of peroxide value, acid value and color of finished linseed oil. Detailed parameters can be found in the following national standard for linseed oil (GB/T8235-2008): quality indexes of pressed linseed oil and extracted linseed oil. Huajian linseed oil, warm reminder!