Introduction This mishnah deals with how people should bake matzot on Pesah to avoid them becoming chametz. The mishnah reflects a reality in which several women shared one oven for baking bread/matzah. We should note that today no one bakes matzah on Pesah. All matzah is baked before Pesah in order to avoid the risk of the dough becoming chametz.
Rabban Gamaliel says: three women may knead at the same time and bake in one oven, one after the other. Rabban Gamaliel says that three women may knead dough simultaneously and then use the same oven, even though the dough of one woman will have to wait while the dough of the other two women is baking. Rabban Gamaliel does not think that the dough will turn into chametz in this short amount of time.
But the sages say: three women may be engaged with the dough at the same time: one kneads, one shapes and one bakes. The sages disagree and think that if one batch of dough has to wait while the other two bake, it is likely that it will turn into chametz. What the women should do is set up an assembly line, one woman will knead, one woman will shape the dough and one woman will bake. If they time it correctly then no one will have to wait to bake their bread.
Rabbi Akiba says: not all women and not all kinds of wood and not all ovens are alike. Rabbi Akiva says it is impossible to a hard and fast rule since some women prepare bread faster than others, some wood makes ovens hotter than others and some ovens cook faster than others.
This is the general principle: if it [the dough] rises, she should slap it with [hands dipped in] cold water. Some commentators explain that this section is a continuation of Rabbi Akiva’s statement but I believe that it is an independent statement. All of the rabbis agree that if the woman begins to see signs of the dough turning into chametz what she should do is slap it with cold water to arrest the fermentation process.