I made some mojo de ajo using Rick Bayless’s recipe. He says that it will keep for up to 3 months in the refrigerator, so I stored it in the refrigerator. The oil seems to have solidified in the refrigerator. If I leave it out for a bit, it melts again, but I am worried that refrigerating olive oil will harm its flavor. Is it bad to refrigerate olive oil to the point that it solidifies? Is it normal for olive oil to do this?
In my experience, that is completely normal and will not harm its flavor at all. You just need to warm it up before serving so that you can re-mix / emulsify your sauce / dressing. It congeals in the fridge much like any other fat will (think butter or bacon grease). Apparently, extra virgin olive oil may suffer from condensation in the bottle affecting the flavor. It may also turn cloudy.
But in general, you should be fine. Even if it does go bad, it should just affect the flavor and not be harmful, just gross. So if it tastes bad, toss it. Otherwise you're fine. Note: I'm just talking about the oil going rancid, not anything else you might mix with it.