Shabbat 38: Intention, Ovens, Hot and Cold Water

Rav Chiya bar Abba is asked about the halacha if one leaves a pot on the stove inadvertently and the food cooks on Shabbat.  After waiting for a day, Rav Chiya bar Abba announces that the food is permitted as long as the cooking is done unintentionally.  He also says that the halacha is no different. 

The Gemara discusses what this last comment might mean.  We are told that there might be a difference between taking action, like putting a pot on the stove.  They also consider the importance of intention, and how we might measure intention in another person.  If someone is lying, what would be the consequence? The rabbis also consider the possibility that overcooking might improve the food, like eggs that have shrivelled to the size of crab apples because they have been left on the stove for so long. 

The rabbis look to each others' behaviours to determine what is permitted.  A frequent response is that this might be a 'rogue' rabbi who does not represent the agreed upon halacha of the community.

We are taught two new Mishnayot in amud (b) of our daf.  The first teaches about an oven or a kupach, a ceramic half-stove with enough room for one pot at its top, things other than stoves that bake.  Regarding ovens that are lit with straw or rakings, we cannot place pots inside or on top of them.  A kupach lit with straw or rakings on Shabbat is like a stove but if it is lit with pomace (pressed olive olives or other substances once the oil has been removed), its legal status is like an oven and so we cannot place pots atop them.

The second new Mishna tells us that one may not place a raw egg next to an urn full of hot water on Shabbat because it might roast slightly.  We cannot even wrap an egg in cloths heated in the sun.  Rabbi Yosei permits this.  We cannot insulate an egg in the sand or road dust.  We see that any cooking, even without fire involved - and lighting a fire is the original prohibition - the rabbis put fences around fences to ensure that we do not become familiar with cooking of any sort on Shabbat.

The Mishna goes on to teach us about the people of Tiberias who ran a cold-water pipe through a canal of hot water from the Tiberias hot springs.  They intended to heat the cold potable water on Shabbat.  The rabbis told them that if the water passed through on Shabbat, it would have the same status as water heated on Shabbat and so it would be prohibited for bathing or drinking.  If it passed through on a Festival, then the water would be prohibited for bathing but permitted for drinking.  This is because on Festivals we are permitted to boil water on actual fire for purposes of eating and drinking.