"Can't you do it yet?" Edward asked. "Have you figured out where you're going wrong on it? Until you get it right, go check the potions book, step by step. Most people have issues with not having the fire under the cauldron quite right, and when its not right, it cooks too fast or doesn't cook through enough. It sounds like that might well be the issue. I see more people not cooking it long enough or hot enough.
"You need to be very gentle with that potion," Kate said. "I've seen Robert do that one hundreds of times. He chooses a lower fire and brews it longer, but he's also figured out there is a bit of a trick to the newt. His friends would simply add a pinch of the newt, and it would curdle. Robert's always came out, and they could never figure out how he was doing it. But I saw him brew it once and figured out how he was doing it.
"He handled each ingredient like he was simply dusting it in, with a very light hand--especially the newt. Try that. Not even a sprinkle. More gentle than that. Try dusting the ingredients on the surface of the potion with as light a hand as you know. From what I've seen, that might be the trick."
"Come to think of it, that's pretty much what I do too," Edward said. "I've just done it so often, I don't pay attention anymore. Its automatic, I suppose."