I use grape seed oil. I don’t know that any oil produces a better sear per se but some have higher smoke points which means they won’t break down and impact the taste of whatever is being cooked in it. I may try refined avocado oil based on the below.
My unprofessional opinion on grill pans v. flat surfaces is that grill pans actually allow the oils and rendered fats to more evenly sear the meat. I usually rock the pan back and forth a few times while cooking The oils are so hot they almost fry the surface like bacon and the grill surface allows them to flow underneath but making contact with the steak. In a flat pan the oils can’t channel underneath the meat as evenly and it’s harder to maintain consistent contact across the cooking surface.
Why Is Oil Smoke Point Important?
Smoking oil isn’t always a problem: there are times when it’s inevitable, such as when you’re stir-frying in an extremely hot wok. Typically, however, smoking is a sign that your oil is breaking down.
When oils break down, they can release chemicals that give food an undesirable burnt or bitter flavor, as well as free radicals that can harm the body. Before using any oil, make sure that its smoke point can handle the cooking method you plan to use.