I will visit 2 balsamic vinegar producers when I am in Modena next month, so I have been doing a bit of study on this thing that some people call "Black gold of Italy".
Turns out, there is an organization in Italy governing Balsamic Vinegar production and only the authentic ones that are produced in the Modena area can be labeled as "Traditional Balsamic Vinegar of Modena". It has to be aged at least 12 years to get this certificate. And then, if the vinegar is aged for over 25 years, it can add an additional label: "Extra Old"
I bought a bottle of "extra old" Traditional Balsamic Vinegar of Modena DOC(Certified) some 15 years ago at William-Sonoma outlet for $49 dollars. Its original price was $249 dollars! At $49 dollars, it was a steal! Too bad there was only one left!
I drizzled some on parmasan cheese and it was delicious!
Just out of curiosity, I did a search on balsamic vinegar on Amazon and to my surprise, there are people selling 100 years old balsamic vinegar!!! And there are more than one kind.
Aged Balsamic Vinegar Tradizionale from Reggio Emilia - Gold Seal - 100 year - 1 bottle - 3.4 fl oz, $258.53
(This one is from Reggio Emilia, not in Modena. It is still certified though. Maybe that's the reason why its price is lower.)
LA DAMA Traditional Balsamic Vinegar aged 100+ years IGP (Case of 4), $2,970
($700+ per bottle. Crazy......)
I'm going to hunt them down in Italy and see if I can bring a bottle home!