Hi I always make ganache 50/50. have been for years. cool it overnight, then whip into a luscious whipped ganche for icing cakes. lately though it won't whip. It separates and goes "grainy" almost immediately. I am not over whipping it. it feels like the fats are not almagamating. Maybe my fridge is too cold and its semi freezing it? maybe I am bring the cream to the boil and its too hot? I don't know why after no problems for years and years, using the same brand of cream and chocolate this is happening. anyone know why please?