A “Heated” Discussion
“The Place of Shechita is Hot”
(Chullin 8b)
In studying our daf, in order to expand our understanding of the halachos of shechitah, we examine other criteria. Many halachos pertain to cooking and heat. It is forbidden to cook on Shabbos and the cooked food becomes forbidden (Chullin 15a). It is forbidden to cook meat with milk. Hot utensils exude and absorb tastes by means of heat, and so on.
All these halachos depend on a temperature defined by Chazal as yad soledes, a temperature from which the hand involuntarily withdraws (see, e.g., Shabbos 40b; Chullin 105a, b). In other words, the temperature classified as “hot” by these halachos is such that a person who comes in contact with it automatically withdraws his hand. However, there is no exact definition that helps us to know the exact temperature from which a person will instinctively withdraw his hand. Many Acharonim have attempted to arrive at an exact number – to translate yad soledes into the measures now in practice and at least determine the exact degree of heat from which, according to all opinions, a person involuntarily withdraws his hand.
A Dispute in Degrees
Rabbi Moshe Feinstein, zt”l, discussed this issue a few times, and in one of his responsa (Igros Moshe, O.C. 4:74) he writes that the range of heat for yad soledes is between 43 and 71 degrees Celsius (110 Fahrenheit to 159 Fahrenheit). In other words, it is clear that a hand does not involuntarily withdraw from temperatures below 43 degrees Celsius, and that all agree that a hand instinctively withdraws from over 71 degrees Celsius. Nevertheless, we have no clear agreement as to the temperatures in between.
Other poskim, however, prove that yad soledes is much less than 71 degrees Celsius, as later defined in our Mesechta (Chullin 105a, b) when the Gemara discusses washing one’s hands (netilas yadayim) with warm water to the degree of yad soledes. It is obvious that one cannot wash one’s hands in such heat (Me’or HaShabbos 1:2, remark 14).
Regarding the temperature from which a hand does not spontaneously withdraw, it has been passed down in the name of the Chazon Ish, zt”l (see Me’or HaShabbos, ibid., se’if 6 and remarks) that there should be no concern for less than 40 degrees Celsius. Rabbi Shlomo Zalman Auerbach, zt”l (Responsa Minchas Shlomo 91: s.k. 8) establishes confirmation for such. The Bahag wrote that an animal’s milk is defined as cool at the time of milking. As the temperature of milk during milking may approach 40 degrees Celsius, it is evident that this temperature is considered cool. Rav Auerbach continues that 45 degrees Celsius is not yad soledes, as proven from our sugya.
A Matter of Absorption
Rav and Rabah bar Bar Chanah disagree in our Gemara as to whether the neck area of an animal (beis hashechitah) is boiling or cool. Accordingly, they disagree whether the beis hashechitah can absorb a forbidden taste contained in the slaughtering knife. If the beis hashechitah is boiling, it absorbs the taste, but if it is cool, it does not. The Gemara then cites an opinion that the disagreement concerns another issue and that both agree that the beis hashechitah is cool.
Rashi and the Rosh rule likewise, and although we rule strictly according to Tosfos that the beis hashechitah is considered boiling (Shulchan Aruch, Yorah Deah 10:2), this is only le’chatchilah (see Shach, ibid., s.k. 14). Aside from that, our Gemara further explains that this matter only concerns the end of slaughtering, but at the start of shechita all agree that the beis hashechitah is cool. Moreover, the Ritva explains (Shabbos 42a) that even those who hold that the beis hashechitah is boiling, “at any rate, it is not so boiling that a hand instinctively withdraws from it” (see Minchas Shlomo, ibid., in the name of the Rosh Yosef, that all agree that this does not really mean boiling).
From here, our path to a definition is short. All we have to do is determine the temperature of the beis hashechitah, and then we can definitively know that it is not yad soledes.
A “Feverish” Duck During Shechita
Indeed, says Rabbi Auerbach, the poskim do not distinguish between the beis hashechitah of an animal and that of fowl. While a person’s average temperature is 37 degrees Celsius (98.6 degrees Fahrenheit) and the average temperature of cattle is 40 degrees Celsius, a duck’s temperature is close to 45 degrees Celsius. At the time of slaughtering, its blood temperature increases by at least one degree Celsius, and if it is sick, it may reach 48 degrees Celsius! But even if we remove the increased temperature at the time of slaughtering and the increase due to sickness, we are still left with the clear knowledge that 45 degrees Celsius (113 degrees Fahrenheit) is not yad soledes.