It all depends on your batter. If the batter is too thick, then the pancakes will be sluggish and undercooked from inside. If the batter is too thin, they will spread out on the pan and won't fluff up. The batter should be thick, but when you drop it from the spoon, it should be able to run slowly and nicely off of the spoon. If you have a few lumps its fine, but its always good to smooth it ours for perfect Pancakes.