The question arose concerning a person who prepared hot water and Hamin (cholent) before Shabbat and placed them on a "blech" or hotplate before Shabbat began, which is, of course, entirely permissible. On Shabbat morning, he noticed that the Hamin began drying out, and he therefore wanted to pour some hot water from the kettle into the pot of Hamin so that the food would not burn before lunch. Seemingly, since the water going into the pot of Hamin is already hot, no cooking occurs as a result of pouring, and we should thus perhaps allow pouring the water.
This question was addressed by numerous authorities, and they all agree that one may not pour water into the pot as it sits on the "blech" or hotplate. Thus, this entire discussion relates to whether one may remove the Hamin from the "blech" or hotplate and then add hot water.
Rabbenu Yona of Gerona (Spain, 1180-1263) addresses this question both in his "Iggeret Ha’teshuba" as well as in his work "Aliyot De’Rabbenu Yona," and rules stringently in this regard. For one thing, he writes, we must be concerned that the water in the kettle may perhaps not be as hot as one assumes. If the water is not hot, then pouring it into the Hamin would constitute cooking the water and thus be a Shabbat violation. Furthermore, Rabbenu Yona contends, even if the water is very hot, it cools slightly during the brief moment it spends in the air, after leaving the kettle before entering the Hamin. It is then reheated as it enters the pot of Hamin, and thus pouring the water into the Hamin would constitute cooking regardless of the water’s temperature in the kettle.
The Ran (Rabbenu Nissim of Gerona, Spain, 1290-1380), however, disagreed, applying to this case the famous Halachic principle of "En Bishul Ahar Bishul" – meaning, once a food has been cooked, cooking it again does not violate the Shabbat prohibition of cooking. Unlike Rabbenu Yona, who held that this rule applies only to solid food, the Ran maintained that even liquids that have been cooked are no longer subject to the Shabbat prohibition of Bishul (cooking). As such, according to the Ran, one may pour water from the kettle into the pot of Hamin (that has been removed from the "blech" or hotplate), because even if the water has cooled, reheating it does not constitute a Shabbat violation. Moreover, the Ran did not accept Rabbenu Yona’s concern that the water in the kettle may not have been hot. Since it was kept on the "blech" or hotplate, we may assume that it was very hot.
Ashkenazim and Sepharadim follow different traditions with regard to this issue. The Rama (Rabbi Moshe Isserles, Poland, 1525-1572), in his glosses to the Shulhan Aruch (Orah Haim 253), codifies the Ran’s position and allows pouring hot water from a kettle into a pot of hot food on Shabbat, and this is the practice among Ashkenazim. Maran (author of the Shulhan Aruch), however, in his Bet Yosef, accepts the stringent ruling of Rabbenu Yona, and notes that this was also the view of Rabbi Yishak Abuhab. This is the position followed by Sepharadim.
If, however, somebody did pour hot water from a kettle into a pot of hot food on Shabbat, then it would nevertheless be permissible for a Sepharadi to partake of the food on Shabbat. Thus, for example, if a person’s host mentioned that he poured hot water into the Hamin on Shabbat morning, the guest – even if he a Sepharadi – may eat the food, even though the water was added in violation of Halacha. Hacham Ovadia Yosef reached this conclusion on the basis of the fact that the prohibition of "Ma’ase Shabbat," eating food that was cooked on Shabbat, constitutes a Rabbinic, rather than Biblical, prohibition. As far as Torah law is concerned, one may eat food on Shabbat even though it was cooked in violation of the Shabbat laws; this food is forbidden only by force of Rabbinic enactment. A fundamental rule in Halacha states that when a situation of uncertainty arises concerning a law ordained by the Sages, we may assume the lenient possibility ("Safek DeRabanan Lekula"). Hence, Hacham Ovadia writes, since the authorities disagree as to whether one may add hot water to hot food on Shabbat, when it comes to partaking of such food we may rely on the lenient position. Thus, even though a Sepharadi may not add hot water to a pot of hot food on Shabbat, if this was done he may nevertheless eat the food.
(See also "Pouring Hot Water Into Hamin on Shabbat," dated May 8, 2008)
Summary: It is forbidden for a Sepharadi to add hot water from a kettle into a pot of Hamin (cholent) on Shabbat, even if the pot of Hamin was taken off the "blech" or hotplate. If, however, somebody did add hot water to Hamin that was removed from the "blech" or hotplate, a Sepharadi may partake of the food on Shabbat.
