[Avodah] Raw food on Erev Shabbos

[Isaac Balbin]

I received the following from the OU's R' Eli Gersten:

> The issur of "Shehiya" forbids one to place food before shabbos on the fire if it will not be edible before Shabbos, unless one uses a blech. The purpose of the blech is that there should be an indication (heker) and prevent one from becoming nervous that their chicken is not cooking fast enough and turning up the fire.
> If one places the chicken in a Metal Box, which will act as one's blech, one can place the chicken in the oven even right before Shabbos. One must still be careful when they remove the chicken from the oven to only open the oven door when the fire is on (otherwise one might inadvertently be causing the fire to turn on).
> 
> The Mishna Berura 254:50 says that one may put a kettle of cold water before Shabbos on a blech to heat up on Shabbos. However, some are concerned that one might remove the kettle pour a cup of water and return the rest, if the water is not yet cooked they will be in violation of cooking on Shabbos, (See Shemiras Shabbos K'hilchaso 1:63 footnote 187) 
> In these matters *one should follow their custom* [my emphasis].