Vintage champagnes offer still other advantages. Most are aged for at least two or three years longer than nonvintage blends are. That extra time allows them to harmonize fully, so they are almost always ready to drink when purchased. Yet these wines can also age effortlessly at home, becoming mellower and toastier with time in the bottle. For me, young, nonvintage champagne, with all its fizzy zeal intact, proves perfect for toasts and late-night revelry. But at a grand holiday feast, vintage champagne's subtler, more layered personality wins out. In fact, these wines are cause for a celebration of their own, no matter the time of year.