Everything I've read says that corned beef should be simmered for 2-3 hrs, and as I recall that works fine. But, my sister-in-law just cooked one that she says was not tender at 2 1/2 hrs, so she cooked it for much longer, and it was still tough.
Is there a "window of tenderness" right around 2-3 hrs? Or maybe she was boiling instead of simmering? What's the difference between simmering and braising, anyway?
I am especially interested because I've corned a whole brisket and I'm looking forward to cooking it today. It's been successful before but I don't remember details.