When Jesus says that the old wine is “good enough”, He is saying that the Pharisees were so satisfied with their biases and presuppositions that there was no way they would listen to anyone who challenged them. Any new teaching that contradicted their own would cause them to "burst", as evidenced by their numerous "outbursts" toward Jesus and His eventual crucifixion. The Pharisees, in essence, were set in their ways (old wine skins). The Pharisees were so attached to their traditions and their interpretations of the Law of Moses that they were unwilling to consider any teaching of Jesus that contradicted it. Jesus’ teaching is compared to new wine and the teaching of the Pharisees is compared to old wine. Why then did Jesus say in Luke 5:39 that the old wine is “good enough”? Only the context can help us. It was for these reasons that Columella stressed new unfermented wine being placed in a new “amphora” (De Re Rustica 12. Therefore a new wineskin would be used to keep the wine fresh and perfectly sweet. An old wineskin would not have been used because there would have been molds and fungus clinging to it and it would have contained the leftover sour remains of old wine, cracks, tears, etc. It could then be safely placed in an unvented wineskin.
How could unfermentable wine be produced? Antiquity reveals that wine could be boiled into a concentrate, filtered, or kept cool in caves, under water, or underground. It follows therefore that not only would the wineskin of Jesus’ parable be unvented, but the wine would be unfermented without the possibility of fermentation occurring. But if your purpose was fermented wine and you left a vent in it, there would be no threat of bursting, new or old. Job 32:19 – “Behold, my belly is like unvented wine, like new wineskins it is about to burst.” If your purpose was to produce fermented wine, you would not only choose a new skin, you would also leave a vent in it to allow the gas to escape.
NEW WINE NEW WINESKIN SKIN
The CO2 gas generated by the process of fermentation would produce enough force to rupture a new skin almost as fast as it would an old if the skin was not vented. This has led some to suggest that Jesus was commending the consumption of intoxicating beverage. A new wineskin, as some have suggested, would be able to withstand the strain of fermentation as it would be more elastic and could easily stretch. And no one, after drinking old wine wishes for new for he says, ‘The old is good enough.’” It is suggested by some that new wine placed in old wineskins would already exist in a state of active fermentation and that the chemical forces of fermentation would therefore rend the fabric of an old wineskin.
But new wine must be put into fresh wineskins. In Luke 7:37-39, Jesus says, “And no one puts new wine into old wineskins otherwise the new wine will burst the skins and it will be spilled out, and the skins will be ruined.