The best type of potatoes to cook on the grill are russet potatoes which are about eight ounces. The potatoes will cook evenly if they are all about the same size. A russet potato and Idaho potato are the same things, but an Idaho potato is a russet potato that came from Idaho. The name russet comes from the color of the skin because they are a brownish color like russet. These are typically long and thick and will cook up to have crispy skin and a fluffy interior. They have a lot of starch, which makes a fluffiness that cannot be beaten.