[International Book - PMID: 17011477 PubMed - indexed for MEDLINE - Primo autore] Short abstract. Traditional balsamic vinegar (TBV) is made by a peculiar procedure, that starts with a thermal concentration of freshly squeezed grape juice, followed by alcoholic and acetic fermentations and, finally, long aging in a wooden barrel set, requiring a volume partial transfer from cask to cask with the consequential blending of vinegars of different ages. The chemical and physical transformations of the vinegar are mainly driven by the low water activity of the vinegar. The time-dependent accumulation of polymeric melanoidins is the major cause of its rheological and sensory behavior of the original and hold TBV.