We are continuing in siman 11, where the Chayei Adam is discussing a fully cooked item which is either a solid, or is a liquid but has not fully cooled. Therefore, there is no concern of bishul to place it on a heat source. However, there is still a concern that only chazarah is allowed. To address the concern of chazarah, the Chayei Adam gave two solutions, either to place it at a distance from the heat source, or on top of another pot which has food inside. In either case, even if the food in question reaches yad soledes bo, we are not concerned for the need for chazara, because it is not a place or method for normal cooking.
The Chayei Adam gives a third solution to address the chazarah concerns. The Shulchan Aruch gives this scenario as well (in siman 253), but while the Shulchan Aruch frames it as a solution for chazarah, the Chayei Adam gives an explanation which would indicate that nesinah lechatchillah would be muttar as well.
The Chayei Adam writes that if a person wakes up on Shabbos morning and sees that their food is drying out and starting to burn, and they are concerned it will burn further, it is muttar lechatchilla to take it off the fire, place an empty pot over the heat source, and replace the food on top of the empty pot. (The new pot cannot have food in it because then there would be an issue of nesinah on the food in the new pot.) This sounds like a classic case of chazarah, in that the food was on the fire from before Shabbos, was removed with intention to replace it, and was replaced in a manner equivalent to garuf v’katum (the empty pot acting as the equivalent of garuf v’katum). This is the understanding of the Mishnah Berurah, and it is the source for the concept of a blech. In the times of Chazal, katum meant to add a layer of ash over the coals. We accomplish the same idea over a gas fire by placing a metal sheet over the flame and separating between the fire and the food.
However, the Chayei Adam does not give the reasoning of the Mishnah Berurah. Instead, he writes that the empty pot on top of fire is better than garuf v’katum. By doing so, he appears to expand the heter of the empty pot beyond being a heter for chazarah, as the Mishnah Berurah assumes. By understanding the empty pot to be better than garuf v’katum, he arguably understands that nesinah lechatchillah would be muttar with an empty pot as well.
In the parentheses, the Chayei Adam adds that if one has a new pot made of pottery, the first time it is placed on the fire helps the pottery harden. If so, if the empty pot used has never been placed on the fire before, placing it on the fire will strengthen the pot, and is a form of makeh bepatish. Thus, the pot must be a pot which was previously used on the fire.
This concern does not apply to contemporary pots, which are made of metal.
Summary
Nesinah lechatchilla is assur on Shabbos, even if the fire is garuf v’katum, because it looks like bishul, or because one may stoke the coals.
Nevertheless, according to the Chayei Adam, there are three scenarios in which nesinah lechatchillah will be muttar, due to the hekker inherent in the placement of the food. Once these scenarios are matir nesinah lechatchillah, they will certainly be matir chazarah. They are:
- When the food is placed keneged hamadurah, further away from the fire,
- When the food is placed on top of another pot which is full of food,
- When the food is placed on top of another pot which is empty. The Mishnah Berurah does not extend this scenario to be matir nesinah lechatchillah, but does apply it to be matir chazarah.