Jars and earthenware pots were brewing containers devised and developed for well-cured sake whose quality could be kept only if hermetically sealed, but a barrel could not be sealed up.
古酒は密閉されてこそ酒質が保たれ、壺や甕はそのために工夫されて発達してきた醸造器であったが、樽では密閉が効かない。