halacha - Sous-vide cooking for Shabbat

Sous-vide is a method of cooking food slowly, at a precisely-controlled temperature. This article in the New York Times reports that this method is becoming more and more accessible to and widespread among home cooks. As I understand it, a typical home setup could be:

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  A large pot, full of water

  
  


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  An electronically-controlled immersion heater, immersed in the water, with its thermostat set to maintain a particular water temperature

  
  


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  Food, sealed in plastic bags or wrap, immersed in the water for a long time

  
  

As explained in the article, cook times could range from a short as an hour to as long as 72 hours, depending on the recipe.

Suppose one wants to use this method to have fresh-from-the-bath meat for Shabbat, setting everything up before Shabbat, and then removing and serving the meat on Shabbat.

Are there any Halachic issues that either would prohibit this scheme altogether or that need to be taken into account in implementing it?

I suspect that there could be issues related to:

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  leaving food under the care of an adjustable device, that you might want to fiddle with, and

  
  


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  causing the device to do more cooking as a result of removing the food from the water.

  
  
  

(Consult your own rabbi before implementing anything suggested here.)

Answer

In a shiur you can listen to here Rabbi Aryeh Lebowitz discussed some of the issues involved with sous vide which is begun before shabbos. They are:

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  Shehiyah. Leaving foods on a heat source.

  
  


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  Garuf Vikatum. Loosely, this refers to treating the heat source.

  
  


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  Hatmana. Insulating the food.

  
  

All these points must be addressed as any one of these can make or break the allowance to leave the food on the heat source. See here for more on the subject.

Whether or not sous vide is problematic concerning any one of these issues involved a machlokes achronim (for ashkenazim).

We would have to rely on two leniencies of the Chazon Ish and ignore the Mishna Berurah in order to alleviate the Shehiyah and Hatmana issues. We would also have to rely on Rav Aron Kotler's opinion about garuf vikatum when covering the controls and ignore Reb Moshe Feinstein's opinion that the actual heat source must be covered.

(He didn't focus on psak for a sfardi, but he did say that the mechaber would not allow shehiya in this case as it is not mitztamek v'ra lo. Cooking it longer does not make the food worse.)

Considering all this he said he did not want to give a hetter to do this for shabbos. Over the last year he spoke to Rabbis Schechter and Sacks but they have not given him a ruling.

(The shiur actually focused on a slightly different situation for which Rabbi Lebowitz was lenient, but all these points were addressed directly as far as shabbos is concerned).