Study Pesachim folio 40A with parallel Hebrew-English text, traditional commentary, and modern study tools. Free access to Babylonian Talmud online.
two wheat grains in boiling water at the same time, lest one move and rest in the slit [tzirya] of the other, thereby preventing the column [dikkula] of boiling water from entering all 4 sides of the grain, and the grain will come to a state of leavening.
And Abaye said: A person may not roast two stalks together, lest water leave one and be absorbed by the other, and it come to be leavened. Rava said to him: If so, one should not even roast one stalk, lest the liquid leave one end of the stalk and be absorbed by its other end. Rather, Rava said: O
The Talmud adds: And Abaye retracted his opinion with regard to that halakha of stalks, as he maintains that anything that is absorbing liquid will not become leavened unless it is fully soaked in water. As Abaye said: With regard to this jug used for drying the stalks by means of roasting, if it
A baraita states: One may not soak barley in water on Passover to make it easier to remove the chaff from the grain. And if one did soak barley grain and it split, it is prohibited. If it did not split, it is permitted.
R' Yosei says: If one sees that the grain is expanding, he should soak it in vinegar, and the vinegar will cause the grain to contract, thereby preventing leavening. However, Shmuel said: The halakha in not in accordance with the opinion of R' Yosei.