Yad soledet bo

"Yad soledet bo" (יד סולדת בו, the degree of heat "from which the hand recoils") is a principle in Jewish law that governs those laws that deal with cooking.

It can be referred to as "scalding" [Rabbi Simcha Bunin Cohen, "The Shabbos Kitchen", Mesorah Publications, Ltd. 1991, page 4] and is the temperature at which someone would reflexively withdraw one's hand from the source of heat. The Talmud additionally refers to this degree of heat as that which would scald a baby's abdomen. ["Bavli" "Shabbat" 40b]

The temperature that constitutes "yad soledet bo" is under dispute. While Rabbi Moshe Feinstein ruled that a temperature of 110ºF (43ºC) must be considered "yad soledet bo" as a matter of practice, he noted that definitive "yad soledet bo" might be as high as 160ºF (71ºC). ["Igrot Moshe" "Orach Chaim" 4:74 "bishul" 103] In practice, the more stringent of the two should be applied. [In following with the principle of "sfeika d'oraita l'chumra", a doubt in a case of biblical law must be ruled upon stringently. If there is a question as to whether or not a violation of "Sabbath" would be transgressed by heating liquids to 120ºF, the response would be in the affirmative, because this temperature exceeds 110ºF; this would be an example of ruling stringently based on the lower temperature. As explained in greater detail further on, liquids that have already been fully cooked are no longer subject to the same restrictions as raw liquids in terms of "bishul" if they remain warm, and in cases of biblical laws of "bishul", pre-cooked liquids should have reached a temperature of 160ºF to be properly considered as pre-cooked; this would be an example of ruling stringently based on the higher temperature.]

A common practice when producing kosher wine is to render it "yayin mevushal" (יין מבושל, "cooked wine"); this is done in order to permit it to be handled by a non-"Shabbat" observer, whether Jew or gentile. ["Kitzur Shulchan Aruch" 47:3] While this cooking process used to be accomplished by bringing the wine or grape juice to a boil, recent technological advances have allowed for flash pasteurization to supplement for this procedure. [ [http://www.nextbook.org/cultural/feature.html?id=578 Nextbook.org, "Purple Haze: Taking a plunge into kosher wines", March 29 2007] ] According to one kosher wine maker, all of its "mevushal" wine is flash pasteurized to at least 185ºF, [ [http://www.abarbanel.com/history.shtml Abarbanel Wine Company: What Kosher Wine Is, and Isn't] ] well above the stringent 160ºF of Rabbi Feinstein. However, there are more stringent authorities than Rabbi Feinstein in this matter, with some requiring 190ºF.fact|date=September 2008

It should be noted that this is not a subjective temperature for which different individuals may determine their own personal "yad soledet bo". The "Drisha" doubts that "yad soledet bo" can be anything but that which would objectively scald an infant's abdomen because the temperature at which people will instinctively withdraw their hand from a heat source is not universal. Other authorites, including the "Rosh", have no qualms about equating the two temperatures. The "Kaf Hachayim" [318:143] quotes the Ben Ish Chai ["Parshat Bo" 5] as stating that one can know if something is not "yad soledet bo" if one can put it in one's mouth without exceeding the normal limitations of the food being too hot for one to eat or drink.

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