This looks to be a Roman style vase. They would pour aged wine into the vase and set it over hot coals. The heat would evaporate all of the impurities, the Romans would allow the wine to heat for a day, after the day of heat then the individual heating the wine would allow it to cool down. It was believed in the Roman culture that during the cooling phase certain gods would place into the wine a strength that the individual was in need of. I learned this from my cousin when he went to Rome three years ago. They allowed him to do this, he said nothing was granted to him, but that it was cool to partake in such a historical belief.