The green color of olive oil comes from chlorophyll, and the amount varies a lot between types — Picual and its blends are the greenest, Manzanilla is the least green.

Some olive oils have a better balance of two types of fats (omega-6 and omega-3) than others — Picual, Manzanilla, Cornicabra, and Sensation are in the healthy range, but Arbequina and its blends are way off.

All olive oils have a lot of one type of antioxidant called alpha-tocopherol — but the amount varies: Cornicabra has the most, Manzanilla has the least.

All olive oils start out with a good balance of fats that lower bad cholesterol, but when you cook them really hot, that balance gets ruined — especially in oils that started with less of the good fats.

When you heat olive oil, it gets more gunk in it — and the hotter you go, the more gunk forms. Some oils (like Armonia) get way gunkier than others (like Manzanilla).