Why? The way that each dairy product is produced, what it comes from and how it's made all comes together to create unique product traits. These characteristics make each milk product taste and feel different from each other-- even though they all originally came from the same raw ingredient.
Olive oil works in the same way. Each different quality grade is produced differently; one grade is the “first press”, while others are refined or come from a different part of the olive. How the grade is made produces a unique oil, and you can taste (and see) the difference between each.
Just like you wouldn’t put heavy cream on your cereal, you’ll want to choose the right grade of olive oil for exactly what you’re making.
If you’re making a product that needs a little kick, or some fresh flavor imparted, you should choose Extra Virgin Olive Oil. That’s why many sauces use EVOO -- it brings a bit of extra life to the final product.
On the other hand, if you need a very light colored oil, or something that doesn’t have much (if any) flavor to it, there is a particular grade you’re going to want to choose. You can picture it as the "skim milk" of the olive oil world.
What you want to use is called Refined Olive Oil.
Refined Olive Oil is the oil made from Virgin Olive Oil that has been refined using a high heat process. That refining process removes much (if not all) of the color and flavor of the oil. The consistency of the oil that’s left is quite similar to that of canola oil. But it’s still made 100% from olives.
It’s believed that this refining process removes much of the health benefits that are in Extra Virgin Olive Oil (like polyphenols), though this fact is strongly debated.
Refined Olive Oil is ideal for any products that need a light color or flavor. The most common examples are below
Here's a quick comparison guide of all of the different olive oil grades.