Toharot, Chapter Four, Mishnah Ten
Our mishnah continues to deal with cases of doubtful impurity involving liquids.
1) Rabbi Yose says: a condition of doubt in the case of liquids is deemed unclean in respect of food and clean in respect of vessels.
2) How so? If there were two jars, the one unclean and the other clean, and he made dough with the contents of one of them and a doubt arose as to whether he prepared it with the contents of the unclean, or of the clean one, such is “a condition of doubt in the case of liquids [which] is deemed unclean in respect of food and clean in respect of vessels.”
Section one: Rabbi Yose holds that if there is a case of doubt involving impure liquids that might have defiled food, the food is impure. But if the doubt involves vessels, the vessels remain pure. He illustrates this in section two.
Section two: In this case, the dough is impure because it might have been made with the water from the impure jar. But the trough in which the dough was kneaded remains pure.