1,122. Leaving Dough Unattended

Chometz u’Matzah 5:13

As long as one is occupied with the dough, even if it is all day long, it will not leaven. If one lets the dough rest to the extent that it will echo when one slaps it, it has already leavened and must be burned immediately. If it doesn’t echo but the dough has rested the time it takes one to walk a mil (2,000 cubits – a little over half a mile), it has leavened and must be burned immediately. Similarly, if the surface of the dough wrinkles so that it looks like one whose hair is standing on end, then it may not be eaten, though one would not be liable for the penalty of kareis if he did so.

Chometz u’Matzah 5:14

Let’s say that two people were both kneading doughs and they stopped at the same time, leaving them both unattended. One of the doughs echoed when slapped and the other one didn’t. In such a case, both doughs must be burned as they are wholly chometz.