How long to keep Buche de Noel?
When did you make it? What is it filled with? I generally think of cake as being good for 3 or 4 days, but in reality it depends on the cake and it is probably fine for longer. A cream filling is more likely to weep over time, but if you have ganache or butter cream as a filling/frosting, the bigger concern would be the cake taking on refrigerator flavors or tasting stale from being chilled so long.
Made on Friday with chocolate and coffee ganache. And, after posting, I decided to call it research and we dug in ourselves.
So to report: While cake and ganache have maintained good flavor and consistency, refrigerator odors are going out to be the problem. The outer piece was just beginning to pick some up, still very slight, even for me, and my husband claims that I can detect anything. But, even if we hadn't cut into it, preservation as a Buche de Noel for Friday was unlikely. Not a total waste, I'm getting it into a sealed container, then on Friday will slice and recycle into some sort of raspberry/chocolate/sponge pudding. Still, it was gorgeous...