Blech - Common Use

Common Use

Rabbi Fishel Jacobs's The Blech Book—The Complete & Illustrated Guide To Shabbos Hotplates gives the following guidelines:-

• The food (including water) intended for Shabbat use should be completely cooked.
• The stove’s gas flames or electric coils are turned on. The blech is placed over these. Alternatively, the Shabbat hot plate, which needs no blech (when it is the type which has no knobs to adjust the heat level,) is plugged in.
• The pot is placed on the blech. It is permissible to place another pot on this one.
• The pot on the blech, or another pot which has been placed on it, may be covered with a blanket, clothing, towel, cloth, etc., to keep the heat from dissipating. One side of the pot should be left partially uncovered.

During Shabbos, the pots are removed according to need. After removal, it is permissible to return the pot onto the blech, following these guidelines:

• The pot should be removed from the blech with the intention to replace it afterwards and held at all times, not leaned onto any surface. (A heavy or unwieldy pot may be partially leaned on a surface, while being held, if there is no alternative.)
• The food must be in the same pot, completely cooked, and has retained at least some of its original heat.

The permissibility of blech (and unblech, below) and the acceptable manner of their use is questioned by several modern kashrut organizations; however, the use of a blech to reheat food on the Sabbath remains very popular among observant Jews.