ohh well, it was worth a shot, I had my mastered chef practically living at Waylon's Haunt, only returning home to sleep for 7 days. He ate only onion rings and watched cookin cable all day and didn't learn anything new.
Though, now that I think about it, he has been at 100% of learned recipes for awhile. The only other thing I could think is that mixology might have a part in it, being a bar food thing. I kind of doubt it though, because his mixology is maxed as well.