Someone in our church group just found out he has a gluten allergy, so we are trying to accomodate him when we bring snacks. I am planning on making schaumtorte which is egg whites, sugar, then fruit on top. But I am supposed to use cream of tartar with the eggs. I know why it is there: to stabilize the egg whites while you beat the heck out of them. But I don't know what it is. Can someone tell me if it is safe for a gluten free diet? Thank you so much!