as mentioned above , alcohol does not age
its my understanding that the USDA (more similar agency )
defines vodka as neutral grain spirits.
and the brand in question does not have added flavor inhancers, which might age
good age , bad age.
is interesting that you mentioned that there is some volume loss.
thus the seal is not 100 % tight.
if the alcohol level is still high enough , nothing should grow in it .
so taste it and see ?
if you don't drink vodka , or add alcohol to a mixed drink
you might be able to use it as an antiseptic ?
or as a
welcome to eG . not many members from Italy
interested in you take of food , of all kinds.