The Rama brings down that after the hands touch the matzas its its left un worked its "Miyad Hichmetz". The mishnah berura says its not immediate but happens after "zman mi-at" If you can explain how much time this actually means I would appreciate it. Are there poskim that give actual numbers of how much time passes until the matzas become chometz?
A K,
Shalom,
It is not explicitly in the Poskim what time is that is not immediate, but the Mishna Berura himself in Biur Halacha also says that the idea is not the immediate range, but rather a short time, but of course he means a time that is less than a Shiur Mil.
It seems that he is simply referring to common sense that it is not possible for dough to become Chametz in an instant, but even if it becomes Chametz faster, it is still in a process and not really immediate.
If you are asking an operative question, I would also use common sense, and not leave the dough for a while without working on it. As soon as there is a feeling that the dough is just standing there, but not in the first few seconds, that's the time to make sure that the dough is worked on. I say this from my practical experience also in baking Chaburah Matzoh, who try to make sure that the dough doesn't just stand, but you can't say that there aren't a few seconds that the dough waits between workers, or until it actually goes into the oven.
Chad Sameach!
Aharon Steiner