Has 24 hours passed?

#846: An Unemployed Pot with Benefits

When rendering foodstuff inside non-kosher utensils kosher or treif (non-kosher), the time that has elapsed since the utensil was last used is often of critical importance. If accidentally frying eggs in the gentile cleaning lady’s pan, we need to ask: "When was it used last?" In the case of mixing milk and meat, the status of kosher utensils is likewise time-dependent, for example, if mistakenly placing a fleishig (meat) spoon in a milchig (dairy) coffee, it would be essential to know if the cup and spoon were recently in use.

Is it young or old?

Generally speaking, when a kli (vessel) is eino ben yomo (has not been used in the previous twenty-four hours), the taste absorbed in its walls is considered nossein ta'am lifgam (imparting a stale taste). As such, food cooked in a pot that is eino ben yomo is not enhanced by the pot’s absorbed flavors. While it is not halachically permissible l’chatchilah (in the first place) to rely on eino ben yomo status to use keilim that are treif or of the opposite type (meat to dairy or vice versa), it is reason to be lenient b’dieved (post-facto). A food that was subject to a kashrus mistake is more likely to retain its kosher status if the taste it draws from the offending kli is “old.” (It should be noted, however, that when there is actual food residue on the kli, there is no difference between ben yomo and eino ben yomo, though other halachic principles may come into play.)

When does the clock start ticking?

The twenty-four hours of disuse begin only once the vessel ceases to absorb from the non-kosher (or meat/dairy) foodstuff, either by its removal from the dish or—if it was left in there—until it cools down to a temperature below yad soledes bo (the degree of heat at which the hand recoils*). In the event that the kli has been removed from an open fire, the countdown cannot begin until the walls of the pot cool down below yad soledes bo.

What if I don’t know?

Can’t recall when it was last used? It’s time to investigate. Ask a family member or a Jewish neighbor who might know (non-Jewish or non-religious household help cannot assert eino ben yomo status, as stated in Halachah #224).

 If that fact cannot be verified, we can usually apply the principal of stam keilim einam bnei yoman (common vessels are assumed idle for the previous twenty-four hours). This halachic rationale is based on a sfeik sfaika (a double doubt, see Halachah #688): Firstly, it is unclear if the kli was engaged at all during the previous day, and even if so, perhaps it was used to prepare a dish that imparts a repugnant taste to the food item presently being cooked and would therefore not render it treif b’dieved.

A utensil, however, that enjoys frequent use cannot be assumed to have been idle and it must be considered ben yomo.

Please note that the information above is insufficient to render a psak—halachic ruling—in most specific scenarios. There are exclusions to the ben yomo rule; for example, it would not apply to davar charif—a sharp food, see Halachah #798. Many other variables determine the status of the food. The rule of ben yomo, as it applies to the utensils involved in the mix-up, are also very specific. If, in the twenty-four hour period, the treif pot was only used for a kosher purpose—or a meat or dairy pot for pareve—like boiling water or the like, the halachic outcome may vary, as well. Also, in specific cases, a mere passing of the night can already render the kli eino ben yomo, leading to even greater leniency. Therefore, it is recommended that a Rav is consulted on these matters.

*ranging from 103° to 114°F, according to various authorities


Practical Halacha: One minute a day. By Horav Yosef Yeshaya Braun, shlita, Mara D'asra and member of the Badatz of Crown Heights.