Difference between different brands of same oil

In practice, the major refined oils are commodity products, and the two different brands may even come from the same factory, but with different labels applied.

Still, it is possible that they are from different producers, and have a different quality standard of refining applied; one may be more aromatic than the other (which is a defect in a refined neutral oil).

The only way to know for sure is to try the less expensive brand. If it has no off-putting aroma, you have a good value.

There are differences between oils. Depending on what quality seeds were sources, how they were stored and handled, and what process was used, there will be a difference in

• how easily they turn rancid
• whether there is residual taste, either from the plant itself or from chemical catalysts added during processing. I had sunflower oil once which was sold as refined, and couldn't use it for baking at all, because it had a really strong sunflower flavor.
• how much it sprays during frying
• the proportions of different types of fatty acids and micronutrients

I have read test reports on oils, which found differences in the above, and also gave notes on things like suitability of the packaging (one plastic bottle leaked a lot, and generally you want dark bottles because oil gets sooner rancid when exposed to light) and proper labelling.

So it matters which brand you buy. But at least in this one test, the quality of the oil was not correlated with price. The best oils were from all price ranges, as were the worst ones. So you have to find a good brand and stick with it. It is not even good enough to rely on such tests, because they only take a sample once, and brands change seed sources and possibly other variables over the years.

Photo of canola oil at various stages of refinement:

Canola oil at different stages of processing. The oil on the far left is unprocessed. Unprocessed canola oil is green because it contains high levels of chlorophyll. The oil on the far right is the same clear yellow as the canola oil you buy in the store. To extend the shelf-life of canola oil and to give it an attractive light yellow colour, processors filter out the chlorophyll.

From "Minor Constituents in Canola Oil Processed by Traditional and Minimal Refining Methods":

Crude canola oil, however, also contains some undesirable minor components such as free fatty acids (FFA), phospholipids, chlorophyll, traces metals (e.g. iron, sulphur and copper), pesticide residues, gums, waxes, and oxidation products. These components may decrease the quality and processibility of the canola oil by causing darkenining, foaming, smoking, precipitation, development of off flavors, and decreasing thermal and oxidative stability.

The highly refined stuff is lighter yellow. I buy that, even if it happens to be cheaper.

America's Test Kitchen did a thorough taste test of "neutral" vegetable oils in the fall of 2011. SAJ said that canola oil is a commodity, that's certainly correct. I doubt that one canola oil can be called better than another based on price. However, ATK did rank Mazola canola oil as superior to the other brands tested.

The winner of the "neutral oil" taste test was not pure canola, but a blend of canola, sunflower and soybean oils.

Take that for whatever you think it's worth. Just don't keep oil above your stove, keep it cool and tightly closed. Whatever oil you use, don't let it get rancid. That will ruin your meal quickly.

I love to bake and while at the beach someone had store brand so I used it. I could tell a big difference in my cupcakes. They were more dry and almost had a grainy texture. I would pay the difference or look for a brand name on sale