Why did my gratin break?

[slkinsey]

Gruyere is a smooth melting cheese that doesn't go grainy, so it's a good choice.

[Chris Hennes]

Do you suppose Peterson is suggesting Parmesan as his top choice purely on the basis of flavor? I still am not sure whether the final graininess in the original batch was due to too much water, or too much heat for the cheese I used, but I'm surprised that if Peterson uses Parm most of the time, he doesn't mention this issue.

[JAZ]

Something that occurred to me recently is a trick I use when making macaroni and cheese. I like the flavor of aged gouda or cheddar but they do tend to get grainy. Adding a small amount of cream cheese seems to keep the sauce much more smooth -- about an ounce per cup of bechamel, added when the sauce has thickened but before I add the cheese. Maybe it would help with this dish as well.