That looks like a plastic bottle, which I consider a red flag, since any decent balsamic vinegar product is bottled in glass; the producers are fussy about that.
From this site, http://www.ciao.it/P...Opinione_795624, the ingredient list:
'Ingredienti: mosto d'uva concentrato cotto, aceto balsamico di Modena 49% (aceto di vino, mosto d'uva concentrato e cotto, colorante: caramello E150d; antiossidante: anidride solforosa), amido modificato di mais, addensante: gomma di xantano.'
[Ingredients: concentrated grape must, balsamic vinegar of Modena 49% (wine vinegar, concentrated and cooked grape must, caramel colour, sulfur trioxide as an antioxidant), modified maize starch, xanthan gum as a thickener].
It's thicker than balsamic vinegar because it has starch and gum added, not because it is concentrated.
Save your money, get a decent but not atrociously priced bottle of commercial balsamic vinegar, and reduce it; heat won't hurt it, although cold can really muck up the consistency irretrevably.