The special "must" that results from this process is placed into a series of wooden barrels for aging. Annually small quantities are carefully moved fromlarger to smaller barrels withtin the series for more thatn 25 years. Vinegar is collected every year from the smallest barrel in each series. The quantity removed for bottling is limited to 1-2% of the total amount in the series. Inside the wooden barrels, many of which have been in our families for over a century, the traditional Balsamic Vinegar undergoes a process of natural fermentation, acidication, and maturation. The completely natural environment where the barrels are stored and the variety of barrel woods, Mulberry, Oak, Chestnut, Juniper and Cherry, contribute to the resulting vinegar's complex flavor. The DOP mark guarantees the highest quality.