Keeps 3 days refrigerated. Reheat gently over low heat and never boil, or the cheese splits. Freezing isn't recommended — dairy and cheese soups separate on thawing and don't recombine well.
The cheese hit soup that was too hot, or it was pre-shredded. Off the heat, a handful at a time, freshly grated.
Blend part of it before adding the cheese. Panera-style versions are partly puréed with some broccoli left whole.
Use whole milk instead of half and half and rely on the roux for body. Cutting the fat too far leaves it thin, since fat carries most of the flavour.