How is Kosterina Balsamic different from supermarket balsamic?

Kosterina Balsamic Vinegar is made in Modena, Italy under a protected geographic designation (PGI) -- the only region authorised to produce authentic balsamic vinegar. Aged around 6 years in 30-year-old oak barrels. Made from 100% Trebbiano and Lambrusco grape must -- no added sugar, caramel, or thickeners. Most supermarket balsamics are wine vinegar blended with caramel and sugar.