So I make Jewish style chicken soup with a chicken carcass and veg boiling it up in water for a couple of hours. When my mum does it the fat how to the top and she skims it off. When I do it there is no obvious fat to skim but once it is cold it becomes a jelly. It is lovely again when warmed up but a) offputting and b) not how it is meant to be. Any thoughts/solutions?