Eiruv Tavshilin

When Can I Cook?

Shavuos this year falls on Friday and Shabbos. Therefore, an eiruv tavshilin must be made on Thursday, erev Yom Tov, to permit cooking on Friday for Shabbos.

It is especially important to emphasize that cooking on Friday for Shabbos is only permitted if the food is ready to eat before Shabbos begins, to the extent that if unexpected guests were to arrive on Friday afternoon, the food could be served to them. One may not, for example, put up a cholent right before Shabbos, since it will not be ready on Yom Tov.

This requirement is especially relevant when Friday is the first day of Yom Tov. The Biur Halacha[1] seems willing to consider the more lenient view that allows cooking even if the food is not ready before Shabbos, in a real shas ha’dchak. He suggests that when Friday is the second day of Yom Tov (which is mi’d’rabbonon) one may rely on this b’dieved if they were not able to cook earlier. However, he is more hesitant to rely on this leniency when Friday is the first day of Yom Tov (which is mi’d’oraisa). Therefore, it is essential that all cooking be completed in a way that the food is ready and fit to be served before Shabbos begins.[2]

There is another interesting halacha that arises when the first day of Yom Tov falls on Friday.

People typically prepare more food for Yom Tov than for Shabbos. As a result, when cooking on Friday (the first day of Yom Tov) for Shabbos, which is also the second day of Yom Tov, one will often prepare not only the standard Shabbos dishes, but additional foods in honor of Yom Tov as well.

Accordingly, the Shulchan Oruch writes that in the nusach recited after making the eiruv — “בדין יהא שרא לן…”— one should add, beyond the standard phrase “מיומא טבא לשבתא,” an additional clause: “ומיומא טבא לחבריה.” This reflects that the eiruv permits not only cooking for Shabbos, but also the additional cooking necessitated by the fact that Shabbos is simultaneously the second day of Yom Tov.

In practice, however, most siddurim and nuschaos do not include this addition. It appears that the prevailing minhag developed to omit it, likely out of concern that its inclusion could be misunderstood to mean that an eiruv tavshilin permits cooking from the first day of Yom Tov to the second in all cases, even when Yom Tov does not lead directly into Shabbos, which is incorrect.

When Can the Eiruv be Eaten?

The eiruv must remain intact until all Shabbos preparations are complete. If the cooked item is eaten or lost beforehand—and less than a k’zayis remains—one may no longer prepare on Yom Tov for Shabbos. Once all preparations are finished, the eiruv may be eaten.

The Shulchan Oruch records a dispute as to whether an eiruv tavshilin is required in order to light Shabbos candles, since doing so is effectively lighting a fire on Yom Tov for Shabbos. L’chatchila, we follow the stricter view. Accordingly, the eiruv should remain intact until after candle lighting.

Although me’ikar hadin the eiruv may be eaten once all preparations are complete, the prevailing minhag is to wait and use the challah from the eiruv as part of the lechem mishnah at the Shabbos meal. Since it was used for one mitzvah, it is appropriate to use it for another.

The Poskim note that this minhag was extended further: to use the challah from the eiruv for lechem mishnah at the first two Shabbos meals without eating it, and then to eat it at seudah shlishis. In this way, it is used for multiple mitzvos—twice for lechem mishnah and once for the mitzvah of eating the Shabbos meal.

For those that have the minhag not to eat bread at seuda shlishis, the challah from the eiruv is eaten by the second meal on Shabbos day.

[1] 527:1.

[2] The Shulchan Oruch HaRav (Siman 527) does not seem to allow for this leniency and always requires the food to be ready before Shabbos starts.