Kashrus Kurrents Winter 2009

Q:       I would like to buy a warming tray that has been manufactured for the Shomer Shabbos community. It is a glass covered warming tray and has a variable temperature dial with a removable knob. It can be set at a minimum temperature of 110 0F and a maximum temperature of 230 0F. It has a sticker on it stating that it is intended solely for the reheating of cooked foods and is not intended to be used for cooking. How may this tray be used on Shabbos?

A:  In order to answer this question, one must have an understanding of the Rabbinic prohibitions of shehiyah and chazarah.  The parameters of these two prohibitions differ for Ashkenazim and Sefardim.  This response will explain the halachah as it applies to Ashkenazim.

Shehiyah:  Shehiyah is the act of placing food on an open flame before the onset of Shabbos […]