- the label of every bottle of EVOO uses short country codes to indicate where the oil came from, which is often multiple countries. this doesn't mean it's worse, but there are more ways some part of it could have not been great.
- extra virgin olive oil is a juice that will go rancid from excessive light, oxygen, or temperature fluctuation. it's basically like red wine. once you open the bottle, use it quickly, and keep it in a dark dry place. make sure the bottle is glass and is darkened.
- high phenolic olive oil is more expensive to produce (and thus buy) but contains more polyphenols.
- more olive oils now carry seals of authenticity. find one, Google it, see if it looks legit. there are many different certifications. Italy was the country with the most EVOO fraud, so be more circumspect with oil from there.
- a list of oils sold in America certified as pure: https://www.aboutoliveoil.org/79-certified-pure-and-authenti...
- all EVOO is cold pressed and unrefined, by definition. ignore any marketing jargon you see on different bottles.
- don't pay a bunch of money for infused oil. buy whatever oil you want, put some aromatics in a jar, pour in oil. use it up in a month.