1. The seller claimed that the wheat was excellent and it turned out to be poor quality. Here the purchaser can cancel the sale.
2. Where the purchaser said that he was buying poor quality wheat, and it turned out to be good quality. Here the seller can cancel the sale.
3. Where the wheat was sold as poor quality and it was, in fact, poor quality.
4. Where the wheat was sold as good quality and it was, in fact, good quality.
In the last two cases, no one can cancel the sale. This would be true even if there was a fluctuation in the price of wheat, and the purchaser, for example, will lose money because of the sale. He cannot claim that he called the wheat “poor quality” simply as a negotiating ploy and that he really wanted to buy good quality wheat (or vice versa, if such a claim is made by the seller). The Nimmukei Yosef explains that this would be true even if it turns out that the “poor quality” wheat was of the very worst quality or the “good quality” wheat was the very best. Since the parties agreed to the sale and the quality was presented in a truthful manner, the sale stands.
The Mishna continues, presenting a parallel case of wine and vinegar. If wine is misrepresented as vinegar or if vinegar is misrepresented as wine, then either the seller or the buyer can cancel the sale. In such a case we do not automatically assume that wine is “good” and that vinegar is “bad,” since it is possible that someone has a specific need for vinegar. Therefore even the purchaser who received wine instead of vinegar can claim that the purchase was mistaken and can demand that the sale be canceled.