What a surprising find.
So being curious I cracked the top and low and behold it was still carbonated, after 8 years in an attic which can reach 140 degrees in the summer. As you can see from the rather blurry picture(sorry), the color is very dark, but with a nice creamy head, it was very clear, not surprising;y, the arome was strongly caramel. On the palate it was smooth and creamy like a schwarzbier. The flavor was caramel and balsamic without the vinegar (like a balsamic reduction). Discretion being the better part of valor, I spat it out and washed my mouth with Listerine.
Still it was an interesting experience.
Just wanted to share.