High oleic, mid oleic, and regular oil
Safflower, sunflower, and canola oils are sold in high oleic, mid oleic, and linoleic (regular low oleic) versions depending on the amount of oleic acid in the oil. The differences in the fatty acid content comes from natural genetic variations in the plants from which these fats come. These differences have been enhanced by conventional plant breeding methods.
Regular low oleic (aka linoleic) canola, safflower, and sunflower oils contain higher amounts of the polyunsaturated fatty acids -- specifically linoleic and linolenic acids. Polyunsaturated fatty acids become rancid fairly quickly in storage and break down quickly when heated.
Mid oleic and high oleic oils contain at least 50% oleic acid, which is a more stable monounsaturated fatty acid, and less of the polyunsaturated fatty acids. These higher-oleic oils will not break down as fast when used in the kitchen for frying and sauteeing. They work better in soap because they are not as prone to becoming rancid (also called DOS, dreaded orange spots) and are sometimes a less expensive alternative to olive oil.
How to tell the difference?
Check the label for phrases such as "good for frying or sauteeing" or "high temperature" or even "high oleic," all of which will tell you the oil is a high oleic version. If you don't see any helpful information like that, then look closely at the nutrition information to find the answer.
For example, the nutrition information on a bottle of safflower oil shows this --
The key information to know is this:
Saturated Fat = 1 gram per serving
Polyunsaturated Fat = 2 grams per serving
Monounsaturated Fat = 11 grams per serving
Total Fat = 1 + 2 + 11 = 14 grams per serving
Or get this number directly by looking at the Total Fat amount on the label.
Quick and dirty estimate
Sometimes an estimate is all you need. Can you tell if the monounsaturated fat is a large part of the total fat?
In this example, the monounsaturated fat is 11 grams and the total fat is 14 grams. The monounsaturated fat is a LOT more than half of the total. Looks high oleic safflower oil to me!
% oleic (monounsaturated) fat = (grams monounsaturated fat per serving) / (grams total fat per serving) X 100%
If the monounsaturated fat is about 70% or higher, it is a high-oleic oil.
If it is roughly between 50% and 70%, it would be a mid-oleic oil.
If it is below 50%, it would be regular (linoleic) oil.
% oleic (monounsaturated) fat = 11 / 14 * 100 = 78.5%
The calculator gives the same answer as the quick and dirty check. This is high oleic (HO) safflower oil.