I'm working on my paella technique, and I'm struggling with the soccarat, the rice crispies that form at the bottom of the rice. In Spain I remember it being both brown and occasionally flecked with black. When I make paella, my soccarat goes black before it gets very crispy. I'm thinking of adding more oil, coating the pan with about 1/8" at the start. What do you think? What temp is best for soccarat formation, high, or medium? I'm using arborio rice not bomba? Is this my problem?