Extra virgin, virgin, pure and pomace explained

All of these grades come from the same fruit. What separates them is how the oil was extracted and whether it had to be fixed afterwards.

Extra virgin

Extracted mechanically only — no high heat, no chemical solvents. It must pass laboratory tests (free acidity no higher than 0.8%) and a taste panel as well. This is the only grade where flavour is formally judged.

Virgin

Same process, but the result did not reach extra virgin standard. Acidity is allowed up to 2.0%. Still genuine olive oil, simply of lower quality.

Pure, or just "olive oil"

This is where the name misleads. "Pure" normally means refined olive oil — treated with heat or chemicals to strip out unwanted taste and smell — then blended with a little virgin oil to put some flavour back. It is stable and cheap, but most of the polyphenols are lost in refining.

Pomace

Made from the leftover pulp — skins, flesh and stones remaining after the first press — using solvents. The lowest grade, usually destined for commercial frying.

If you are buying for flavour and polyphenols, extra virgin is the only grade worth it. For high-heat frying in volume, a lower grade makes more sense on cost.