Jeremiah then tells how people are going to react, "They will no longer say, 'The parents have eaten sour grapes and the children's teeth are set on edge.'"
According to the commentary by John M Bracke, Jeremiah means that they are going to stop complaining about the perceived unfairness of the exile but rather will recognize that they had deserved to be punished (also see Jeremiah 18:1-32).
In his commentary on Jeremiah, R.E. Clements interprets this not as an expression of a doctrine or a defense of the principle of shared family responsibility but rather to give voice to despair:
It is equivalent to "What is the use of trying--our ancestors have done wrong and we are paying the price!".Their punishment had been real and they and their descendants had recognized it as deserved. But, new life is possible.