It is a special vinegar produced by obtaining the juices (must) from pressing the grapes and this must is cooked for hours over direct fire until a brown, syrupy liquid with a good grape smell is obtained (cooked must.) This cooked must is then aged in wooden barrels for a minimum of 12 years following the Solera System.
These barrels are made of different types of wood, such as cherry, chestnut, oak, mulberry, ash, etc. and they each hold different capacities.
The Solera system, also called ‘topping up,’ calls for the continuous (every year) and consequent topping up of the cooked must into the next smaller barrel so each year the ‘newest’ cooked grape must is blended with the one from the previous year already contained in the barrel.