May one eat food warmed in the absence of a blech or hotplate?

We differentiate between the opinion of the Mechaber and the Rama.

The Mechaber holds that food may l’chatchila [1] be placed on an empty flame before Shabbos if it is fully cooked and 'mitztamek v'ra lo', (in the process of shriveling or drying out). [2] If one unknowingly acted contrary to the halacha and placed food less than that degree on an open flame, it depends:

• If it is fully cooked and 'mitztamek v'yafeh lo', (shriveling beneficially) one may consume the food. The poskim explain that since the food was fully cooked when placed on the flames, the benefit from any additional cooking is marginal and the food is therefore permitted. [3]
• If not fully cooked one may not consume the food until after Shabbos. [4]

What does the Rama hold?

According to the Rama, one may place on open flames food cooked to the degree of ma’achal Ben Derosai – half cooked, before Shabbos. [5] (We learned that according to the Chazon Ish this is l’chatchila and according to the Mishna Berura it is permitted only when necessary but not l’chatchila).

Food cooked less than the degree of ma’achal Ben Derosai placed on flames before Shabbos may not be eaten until after Shabbos. [6]

Is the food prohibited for all?

The food is prohibited unto all. This includes the person who placed it on the fire, that person’s household and everyone else. [7] Consequently one cannot exchange one’s food with a neighbor (even when there is an eiruv), because the neighbor is not permitted to consume that food on Shabbos.

When may one consume this food?

We find a machlokes in the matter. There is a concept in halacha called bichdei she’ya’asu – the time it takes. If, for example, the food was only half cooked when placed on open flames before Shabbos, one calculates the ‘time it takes’ to become fully cooked. After Shabbos one may eat this food after ‘that time’ - bichdei she’ya’asu.

With respect to this case we have a machlokes, where one opinion holds that one must wait bichdei she’ya’asu after Shabbos, [8] while the other opinion holds that one may consume it right after Shabbos without having to wait bichdei she’ya’asu. [9] It appears that the M”B rules like the latter opinion and the Shulchan Aruch HaRav rules like the former. [10]

What is meant by ‘unknowingly’ placed?

Unknowingly or b’shogeig means that one was unaware of the halacha, thinking it was permitted, or if food was left there unintentionally before Shabbos. [11]

What if one placed it on open flames knowing that it was wrong?

This is called 'meizid' or deliberate and according to all opinions it may only be consumed after Shabbos, plus the time of bichdei she’ya’asu. The Mechaber adds [12] that even if the food was fully cooked but not 'mitztamek v'ra lo', one may only consume it after Shabbos.

Practically this is a strange case, because one who deliberately places it on open flames contrary to halacha will not be interested to know whether it may be consumed or not.

Nevertheless we live in a strange world and it is possible that remorse eats at that person’s heart and after placing it there he decides to act in accordance with halacha. As mentioned, the food is prohibited until after Shabbos plus bichdei she’ya’asu.

What is the rationale to wait bichdei she’ya’asu?

Rashi learns [13] that since the food improved on Shabbos, one must not gain benefit from an action performed contrary to halacha. The Rambam is concerned that if one was permitted to benefit from the food right after Shabbos one might be tempted to repeat it. By waiting bichdei she’ya’asu one will not gain from violating the halacha. [14]