5786/2026
Opening an Oven or Warming Drawer – Rav Willig vs. Rav Neuberger
OU Kosher (Daf HaKashrus 19:10 pp.59-60) and theaStar-K(https://www.star-k.org/articles/kashrus-kurrents/476/oven-kashrus-for-shabbos-use/)doanota permit opening a warming drawer on Shabbat since one may ignite the oven’s fire. Although many Poskim share this concern, Rav Mordechai Willig is not concerned about this, since one does not intend to ignite the fire and there is a delay between opening and ignition (a Psik Reisha L'Achar Zman, see the Shiltei Gibborim, Shabbat 45a:2; The Laws of Cooking and Warming Food on Shabbat pp. 143-144).
However, Rav Yaakov Neuberger (The Laws of Cooking and Warming Food on Shabbat, p. 280 in the Hebrew section) questions Rav Willig’s assertion, noting that he investigated the matter and found that after opening the oven, the fire ignites in less than ten seconds. In response, my wife Malca and I experimented in our oven and found that in six tries, it took from seventeen to thirty seconds for the fire to turn on from the time we opened the door. Significantly, the Star-K (ibid.) regards the result of opening the oven door as grama (indirect), fitting the results in the Jachter home.
Rav Yisrael Rosen of the Zomet Institute (Techumin 34:23) defines a delay for grama purposes as ten seconds, arguing that ten seconds is the amount of time which people in general regard as a delay. The Star-K defines the delayaasafifteenasecondsa(https://www.star-k.org/articles/kashrus-kurrents/4629/oven-kashrus-for-yom-tov-use/). I reported my findings to Rav Willig, who was grateful for our defense of his ruling.
Even according to Rav Neuberger’s findings, there is room to be lenient, as the Grama time delay might be defined as shorter than ten seconds. Rav Yisrael Rosen writes (Techumin 34:23) that the Zomet Institute prefers to use ten seconds as a time delay, but in case of great need, they consider a delay of two to three seconds sufficient. Elsewhere, the Star-K (https://www.star-k.org/articles/kashrus-kurrents/6473/urns-pump-pots-in-halacha-part2/) writes that five seconds suffice to count as Grama. These numbers are based on the idea of Toch Kedei Dibur (the time it takes to say “Shalom Alecha Rabi”) being considered an interruption in many Halachic contexts (see, for example, Nedarim 87a). Accordingly, a delay of this length suffices to disconnect the person from the resultant action, the definition of Grama.
The Shiltei Gibborim
Another potential criticism of Rav Willig’s approach is that the Shlitei Gibborim only presents as a possibility that Psik Reisha L'Achar Zman is permitted. One may respond that Rav Shlomo Zalman Auerbach (Teshuvot Minchat Shlomo 1:10) permits opening a refrigerator on Shabbat even when its motor is running based on the Shiltei Gibborim. Moreover, Rav Auerbach and Rav Willig support their contention on our entering and leaving our thermostatically regulated homes on Shabbat despite the inevitable resultant impact of the summer heat and winter cold on these systems. Thus, we have accepted the Shiltei HaGibborim’s suggestion in practice.
Rav Neuberger responds that it is not inevitable that one will trigger the heating when entering the house in the winter. He argues that the heat may already be running at the time. Moreover, he suggests that the body heat of those entering the house may help balance out the cold air.
We may respond to the first point, that we have never heard of people not entering the home until the people inside report that the heat is already running (as some do regarding opening a refrigerator when its motor is not running. Regarding the second point, it is difficult to imagine that Rav Neuberger’s point is true, especially on very cold days.
Rav Shlomo Zalman Auerbach’s Lenient Consideration
Another point supporting Rav Willig is an argument Rav Auerbach advances that causing fire or the motor to go on earlier is not considered melacha, since the person is not introducing anything new; rather, he is merely altering the pace and rhythm of the device’s cycle. Rav Auerbach writes about refrigerators:
Allowing heat into the interior of the refrigerator does not cause it to function any differently. Rather, the refrigerator is built such that it turns on the motor when a certain temperature is reached, and by letting warm air in, one merely causes that to happen sooner, but does not cause anything to happen faster than it would have otherwise. It seems, therefore, that even if one were to intentionally and immediately cause the motor to run sooner, because this melacha is transient, and one also cannot say that this causes the refrigerator to attain its function… it is not even a rabbinic prohibition.
Rav Auerbach’s point is equally relevant to causing the oven fire to ignite by opening its door. Although no other Poseik advances this argument, and even Rav Auerbach himself did not rely on it alone, it is a potent S’nif L’Hakel, lenient consideration.
Conclusion
The consensus appears to be concerned about opening ovens and warming drawers when their fire is not ignited (see, for example, Dayan Yaakov Yechzekel Posen, Kitzur Hilchot Shabbat p. 51). However, Rav Willig is not a lone voice. Rav Dovid Ribiat (The Thirty Nine Melochos, p. 1220) is also lenient, noting, based on a ruling of Rav Moshe Feinstein (Teshuvot Igrot Moshe O.C. 4:74 Bishul – 28), that “Most ovens will not automatically ignite when the door is opened,” and that it is therefore permissible to open the door of these ovens on Shabbat. He further cites (n. 86 ad. loc.) an expert who reports that, “In general, the thermostats in ovens are not that sensitive to the extent that they would quickly change due to a temperature change.”
If one wishes to be strict about this matter, it is not difficult to do so, as one merely needs to wait until the fire ignites before opening the oven (the oven fire turns on and off fairly frequently). Moreover, the OU and Zman Technologies have developed a system that enables one to open the oven without igniting the fire (https://www.zmantechnologies.com/shabbos-keeper-ovens).
In terms of a warming drawer, the OU recommends that caterers ask a non-Jew to open the door. The Amirah L’Nochri prohibition does not apply to a Psik Reisha (Mishnah Berurah 277:15, Teshuvot Igrot Moshe Orach Chaim 2:68, and Shemirat Shabbat Kehilchatah 31:1 and footnote 1). However, those who are lenient have strong authority and reasoning upon which to rely.