Makhshirin, Chapter Three, Mishnah Three
1) One who drew hot bread off the side of an oven and put it upon the mouth of a jar of wine:
2) Rabbi Meir declares it susceptible to uncleanness;
3) But Rabbi Judah declares it insusceptible.
4) Rabbi Yose declares it insusceptible in the case of wheat bread and susceptible in the case of barley bread, because barley absorbs [liquids].
Section one: The bread mentioned here must be bread that was mixed with fruit juice which does not cause flour to be susceptible to impurity. [If the bread was already susceptible because it had been mixed with water, then this mishnah is not an issue].
Section two: Rabbi Meir says that the hot bread, no matter the kind, will draw wine out of the barrel and therefore it is susceptible to impurity.
Section three: Rabbi Judah says that the bread does not draw off the wine and therefore it is not susceptible.
Section four: Rabbi Yose distinguishes between wheat bread, which is less absorbent and barley bread which is more absorbent. Only the latter is susceptible to impurity.