Mishnayos Challah Perek 3 Mishnah 1

אוכלין עראי עד שתתגלגל – when it becomes combined well, because there is no designation of the term “dough” until it is rolled [and shaped].

ותטמטם בשעורים – because the dough of barley scatters and does not combine well with the dough of wheat, but rather kneads into a cohesive shapeless mass in the hand

חייב מיתה – for its work had been completed and it is an eatabler forbidden pending the separation of sacred gifts, becomes [liable for] death [if consumed].

מגבהת חלתה – it is the ordinance of the Sages regarding ritually pure dough to rush to separate Hallah in purity, lest the dough become ritually impure, for the essence of the Mitzvah is to wait until the completion of the kneading.

ובלבד שיהא שם חמשת רבעים קמח – that had been combined in water, for less than this, the dough did not reach to the general obligation for Hallah. And there are books which have the reading: ובלבד שלא יהיה שם חמשת רבעים קמח/ and as long as there will not be there five-fourths flour, that is to say, that there should not remain five-fourths flour that was not mixed/combined with water, for if there remained five-fourths, they would not be exempt from Hallah if he separated it prior to be rolled [and shaped]. And in the Jerusalem Talmud, we prove that if he said, “Behold this is Hallah,” on the leaven and on the dough and on the flour that remains after the dough had been rolled [and shaped], all of it is sanctified/dedicated in my hands for the sake of Hallah, this would be permitted. And similarly, a person should teach the women to say this as we separate Hallah, immediately after rolling [and shaping] the dough, but before the forming of the bread.