The grape juice was allowed to stand and ferment in the collecting vessels for about six weeks. A sludge known as lees formed at the bottom of the vessels. The wine was then tipped up gently into jars without disturbing the sediment (Jer 48:11). The jars were sealed with clay, but there was a small hole by the handle that allowed the gases released during the remaining fermentation to escape. When the process was complete, the hole was sealed with a blob of wet clay and the owner’s name or seal was put on the clay. It was possible to put the wine in wineskins (goatskin bottles), but if the gases, then it would burst and the wine would be lost. This is the point of Jesus’ illustration in Matthew 9:17.