Beer Cheese Soup

How to make a cheese soup without clumping?
I wonder what the trick is to make a cheese soup without the cheese base agglutination chewable balls. Any advice anyone? For soups such as Beer and Cheese Broccoli Cheese
Follow a recipe. Add some grated cheese by little, stirring constantly. Wait until the cheese melts before adding the next handful. Keep the temperature high enough to melt the cheese, but not high enough to boil.
Beer Cheese Soup