If we use a crockpot on Shabbat, what do we need to do to it so that it is not “problematic”?
In answering this question I will assume that the reader has a basic understanding of הלכות שהיה, חזרה והטמנה.
First, you have to examine your crockpot and answer some questions.
- Does your crockpot sit on a base that heats the food, with the sides uncovered and exposed to the air?
- Does the crockpot surround the pot containing the cholent so that your pot fits into another pot?
If the pot with the food in it is surrounded by the crockpot on the bottom and the sides:
- Are the heating coils only on the bottom?
- Are they only on the sides and not on the bottom?
- Or are they on the bottom and around the sides of the pot, all the way up to the top of the pot?
You can determine this by turning on the crockpot and feeling around the inside to see where heat is being generated.
In situations 1-4 there is no risk of hatmana and you should just prepare the crockpot as you would any pot put on a gas range. (I assume the crockpot is normally used to slow-cook raw food, not just to warm food that was previously cooked.) Make sure the food is fully cooked before the onset of Shabbos or place two layers of heavy-duty foil inside the crockpot to separate the heat source from the pot containing the food. The foil is meant to reduce the flow of heat and will act as a reminder not to touch the controls to raise the heat. For the latter reason, the foil should come up over the sides of the pot and be visible when you look at the crockpot. The first function of the foil is to avoid an איסור שהיה so that food that was not fully cooked before Shabbos can stay on the heat source and continue cooking. ((If the food has been cooking for more than half the time it would take to fully cook, then it doesn’t need a blech. See Rema O.C. 253:1 and Chazon Ish O.C. 37:3 and 37:6, which explain that lechatchila we follow Chanania’s opinion (the second opinion presented in S.A.). [The Biur Halacha maintains that lechatchila it is best to follow the opinion of the Chachomim (the first opinion mentioned in S.A.) and always place a blech under food before Shabbos unless it is mitztamek vera lo.] I have purposely defined the shiur of ma’achal ben derusoi in units of time based on the Chazon Ish (O.C. 37:6), but if the food were still not edible to most people after being cooked for half the time, it would seem prudent to be machmir and insist on ablech (see Kaf Hachaim 253:28).
In a case of great need, one can consider food cooked for a third of its usual time to be ma’achal ben derusoi, in which case a blech is not necessary (M.B. 253:38).)) This is necessary even if the controls are set to the highest setting. ((באג”מ או”ח ח”ד סימן ע”ד דיני בישול אות כ”ה כתב דאף אם ליכא שום חשש שמא יחתה צריך גו”ק מטעם לא פלוג בכל שהייה ע”ג אש מגולה, ועוד אע”ג דלא חיישינן לשמא יכבה אש של עצים שצריך לזה מים ובכה”ג לא גזרו, מ”מ חיישינן לכיבוי שיכול לעשותו בקלות, ועוד דאיכא למיחש שמא יקטין החום ואח”כ יגבירו אותו. )) The foil then serves as a blech allowing שהיה.
Once the foil I just described is in place, its status as a blech can also serve ablech’s second function, which is to enable chazara. Now, one could potentially take the inner pot with a fully cooked cholent out of the outer pot on Friday night and return it to the crockpot (with the blech in place), provided that the rules of chazarawere followed. ((Some models of crockpots have a thermostat that turns off the electric current to the coils when a high temperature is reached and activates the electric current when the temperature drops too low. If you have such a crockpot, you have to be careful not to cause the thermostat to activate the heating of the coils when returning the inner pot to the outer pot (chazara). This could happen if the crockpot reached a high temperature, turning off the electric current, while the inner pot was sitting in the outer pot, and then, after the inner pot was removed, the outer walls of the inner pot cooled down significantly. When the inner pot is put back into the outer pot, the thermostat will likely sense a sudden drop in temperature, activate the electric current, and heat the metal coils. To avoid this, just wait until the thermostat activates the crockpot on its own before returning the inner pot. ))
In situation 5, however, we have to be concerned about hatmana bedavar hamosif hevel. The simplest solution is to raise the pot above the floor of the crockpot with some rocks, tin foil balls or something else that will withstand the heat there and separate the pot of food from the bottom coils. Then estimate the surface area of the cover of the pot (which is always going to be exposed to the air), the area of the pot that is above the side coils, and the area of the bottom of the pot that is now distanced from the coils. Should the area of these three places be greater than the area of the pot surrounded by the side coils, there is no problem of hatmana. Now all of the rules mentioned earlier for situations 1-4 are applicable.
Once the pot of food is raised in the crockpot, the best thing to do is to have the cholent fully cooked before Shabbos. In that case you don’t need a blech, which means that you don’t have to put tin foil all around the crockpot. Without a blech, however, chazara isnot permissible.
When shopping for a crockpot it is advisable to choose one that does not have a thermostat and is not fully surrounded by coils on the bottom and sides (i.e., types 1, 3, and 4 above are preferable).