We begin our study of the Daf Yomi for page 42 of Masechet Shabbat. This study has been dedicated by Benjamin Stabras for a complete recovery for all the sick of Israel, a healing of the soul and the body; may their recovery be near, and let us say, Amen. We start on the first side of the page, beginning with the discussion introduced by the Baraita. This teaching presents three distinct opinions: those of Beit Shammai, Beit Hillel, and Rabbi Shimon ben Menasya. To understand these views, we must first recall a law found in Masechet Pesachim and discussed in Yoreh Deah regarding the principle that the bottom overpowers. This rule states that when one substance falls onto another, the substance on the bottom dictates the thermal outcome. This principle is central to the laws of cooking on the Sabbath.
The Sages taught that a person may pour hot water into cold water. Because the bottom substance is cold, it overpowers the hot water being poured in, cooling it down rather than being heated by it; therefore, no cooking occurs. However, one may not pour cold water into hot water. In this case, the hot water on the bottom overpowers the cold water, heating it up and resulting in the prohibition of cooking on the Sabbath. This is the logic of Beit Shammai. It is important to note that while this is the law regarding a primary vessel—one that was heated directly on the fire—Beit Shammai issued a further rabbinic decree. They forbade pouring cold water even into a secondary vessel—one into which hot liquid was poured after being removed from the fire. Although a secondary vessel generally does not have the power to cook, they forbade it to prevent someone from mistakenly doing the same with a primary vessel. Tosafot confirms this innovation, noting that Beit Shammai specifically made this decree regarding a secondary vessel because of its resemblance to a primary vessel.
Beit Hillel, however, argues that it is permitted to pour hot into cold or cold into hot. This seems to contradict the principle that the bottom overpowers, which would suggest that pouring cold into hot should result in cooking. The Gemara clarifies that Beit Hillel is referring specifically to a cup. A cup is a secondary vessel, as one does not cook directly in a cup; rather, the liquid is transferred into it. Tosafot explains that Beit Hillel only permits this in a secondary vessel, but they would agree with Beit Shammai that pouring cold water into a primary vessel is forbidden. The Gemara continues by distinguishing the cup from a bath. In a bath, which functions as a primary vessel, everyone agrees that while you can pour hot water into cold, you cannot pour cold water into hot because the heat of the primary vessel will cook the incoming cold water.
According to Rashi, this discussion demonstrates that Beit Hillel subscribes to the principle that the bottom overpowers. However, many commentators, including Tosafot, point out a dispute between the Sages Rav and Shmuel in Masechet Pesachim. Shmuel holds that the bottom overpowers, while Rav argues that the top overpowers. If Beit Hillel clearly follows the rule of the bottom, how could Rav argue against them? Furthermore, even those who say the bottom overpowers generally admit that the top substance can still affect the bottom substance to the depth of a thin layer. If so, even pouring hot water into cold should be forbidden because it would cook the very top layer of the cold water. Because of these difficulties, Tosafot suggests that this discussion is not about which layer overpowers the other, but rather about the volume of water. When pouring a small amount of hot water into a large amount of cold water, it is permitted. When pouring cold into hot, the smaller amount of cold water will inevitably be cooked by the larger volume of hot water. Rashi, however, maintains that the issue is indeed about the bottom overpowering, and he argues that while the top may impart flavor to a thin layer, it does not actually perform the act of cooking on the Sabbath.
A third opinion is offered by Rabbi Shimon ben Menasya, who forbids even pouring hot water into cold water. The Gemara seeks to clarify his position and whether it applies to a bath or a cup. Rav Nachman rules that the law follows Rabbi Shimon ben Menasya. This leads to a discussion regarding a bucket, which sits between a cup and a bath in its legal status. Rav Yosef initially thought that a bucket should be treated like a bath. Even though a bucket is a secondary vessel, which typically does not cook, the Sages may have issued a decree because the water in a bucket is intended for washing rather than drinking. Since a person wants bathwater to remain very hot, the Sages were more stringent. Rashi notes that because of this desire for high heat, Beit Hillel would forbid pouring cold water into a bucket of hot water even though it is a secondary vessel.
However, Abaye cites a tradition from Rabbi Chiya stating that a bucket is not like a bath, meaning it is permissible to pour cold water into it. This creates a logical puzzle. If the law follows Rabbi Shimon ben Menasya, who forbids even pouring hot into cold, and if we treat a bucket like a bath, there would be no way to wash one's face with warm water on the Sabbath. Even if the water was heated before the Sabbath, it would often need to be tempered with cold water to be usable. If Rabbi Shimon ben Menasya forbids all mixing in both baths and buckets, washing would be impossible. The Gemara resolves this by clarifying that Rabbi Shimon ben Menasya was not arguing against the rule for baths, but rather against Beit Hillel regarding the cup. While Beit Hillel allowed pouring cold into hot in a cup, Rabbi Shimon ben Menasya forbade it. However, he would agree that pouring hot into cold in a bath is permitted. Thus, the law allows for washing.
The Gemara then asks if Rabbi Shimon ben Menasya simply holds the same view as Beit Shammai, who also forbade cold into hot. It explains that his unique contribution was the claim that there was never a dispute between Beit Shammai and Beit Hillel on this matter; he believed both agreed it was forbidden. Later, Rav Huna the son of Rav Yehoshua observed that the Sage Rava was not concerned with the type of vessel used; he would pour cold water into hot water in any secondary vessel, whether a cup or a bucket. Rava relied on a Baraita from Rabbi Chiya which states that a person may pour a jug of water into a bucket of water, whether hot into cold or cold into hot. Rav Huna questioned this, suggesting the Baraita might mean placing the entire jug into the water rather than pouring the water out. Rav Ashi clarified that the language of the Baraita explicitly uses the term for pouring, proving that pouring cold water into a hot secondary vessel is permitted.
Ultimately, the Gemara concludes that a bucket is not treated like a bath, and therefore it is permitted to pour cold water into it. Regarding the final ruling of Rabbi Shimon ben Menasya, there are different interpretations. One view is that he only forbids pouring hot water into cold water specifically in a bath, but permits it in a secondary vessel. Another view among the early commentators is that he remains stringent even in a cup, arguing against the Baraita cited by Rava. The core of the debate rests on whether we apply the strictures of a primary vessel to secondary vessels when the water is intended for washing.
The Mishnah then moves to a new topic regarding pots and cauldrons. If these primary vessels were removed from the fire while boiling, one may not put spices into them on the Sabbath. Even though the pot is no longer on the fire, a primary vessel has the power to cook as long as it remains at a boiling temperature. Rashi explains that this applies even during twilight, as the heat remains intense. However, one may put spices into a bowl or a deep dish, which are secondary vessels, because a secondary vessel does not have the power to cook. Rabbi Yehuda offers a different view, stating that spices may be added to any vessel unless it contains vinegar or brine, which are sharp and facilitate cooking. The Gemara clarifies that Rabbi Yehuda is actually being lenient; he permits putting spices even into a primary vessel that has been removed from the fire, provided it does not contain those sharp liquids.
Finally, the Sages discuss the status of salt. Rav Yosef initially thought that salt is like spices: it cooks in a primary vessel but not in a secondary vessel. Abaye countered this with a teaching from Rabbi Chiya, suggesting that salt is actually more easily cooked than spices and can even be cooked in a secondary vessel. This would contradict the view of Rav Nachman, who stated that salt is as difficult to cook as the meat of an ox, which requires the intense heat of a flame. A second version of this discussion suggests that Abaye cited Rabbi Chiya to prove that salt is harder to cook than spices, meaning it would not be cooked even in a primary vessel off the fire. This version aligns with Rav Nachman, concluding that salt only cooks in a primary vessel that is still on the fire. According to this more lenient view, it would be permissible to add salt to a primary vessel once it has been removed from the heat.