During the upcoming Yom Tov of Shavuot, we will have an opportunity to make an Eiruv Tavshilin. (For this Shavuos, even those who live in Eretz Yisrael will have this opportunity.) In this article, we will present an introduction to the concept of Eiruv Tavshilin and some of its basic parameters
.(Note: The words to be said and the blessing are to be found at the end of this article along with an English translation>)
Many food-related melachos (herein this article referred to as “cooking”) are generally permitted on Yom Tov for the needs of that day of Yom Tov. However, it is forbidden to do melachah (see note) – or even to prepare – on the first day of Yom Tov for the second day of Yom Tov, and on Yom Tov (even the second day of Yom Tov in chutz la’aretz) for the day after Yom Tov – even when the day after Yom Tov is Shabbos.
When Shabbos follows Yom Tov (or coincides with the second day of Yom Tov), a challenge is presented: How can one practically cook food for Shabbos? Since one may not cook on Shabbos and one may not cook on Yom Tov for another day (even for Shabbos), one would have to cook all the food for Shabbos before Yom Tov begins. In earlier generations, before refrigeration existed, keeping such food fresh would be virtually impossible. In addition, there is a mitzvah to eat hot food on Shabbos. In earlier generations, even if one cooked food before Yom Tov, one would be unable to keep the fire burning on Yom Tov for the sole purpose of keeping food hot for Shabbos.
To solve this untenable situation, Chazal created the institution of Eiruv Tavshilin. By making an Eiruv Tavshilin before Yom Tov, one is permitted to cook on Friday of Yom Tov for purposes of Shabbos. Thus, if one makes an Eiruv Tavshilin on Thursday, Erev Shavuot, one would be permitted to cook on Friday of Shavuot for Shabbos.
It is important to note that the Eiruv Tavshilin only allows one to cook on Thursday night/Friday day of Yom Tov for Shabbos, not on Wednesday night/Thursday day of Yom Tov for Shabbos, and not on Wednesday night/Thursday day of Yom Tov for Thursday night/Friday day of Yom Tov. Moreover, it goes without saying that the Eiruv Tavshilin permits one to perform on Thursday night/Friday day of Yom Tov for Shabbos only those melachos that one would be permitted to perform on Yom Tov for that day of Yom Tov.
How does Eiruv Tavshilin work? The Mishnah writes that one may prepare a cooked food on Erev Yom Tov (for an Eiruv Tavshilin) and “rely on it for Shabbos.” The Rema writes that when one cooks the Eiruv Tavshilin food on Erev Yom Tov for Shabbos (see note), one has thereby already started the cooking for Shabbos. Therefore, cooking on Friday for Yom Tov is not starting the cooking process for Shabbos, but merely completing it, which is permitted. He explains that the name Eiruv Tavshilin – a mixture/joining of cooked foods – refers to this merging of the food cooked on Erev Yom Tov for Shabbos and the food cooked on Friday of Yom Tov for Shabbos.
A question arises: As mentioned above, cooking on Yom Tov for Shabbos is inherently prohibited. If we are to assume that doing such is prohibited Biblically, how could making an Eiruv Tavshilin – which is a Rabbinic institution – allow one to cook on Yom Tov for Shabbos? The answer must be that cooking on Yom Tov for Shabbos is actually permitted Biblically, and only prohibited Rabbinically. Since the prohibition is Rabbinic, the Rabbis may enact a mechanism whereby the prohibition is waived. But since one is Biblically prohibited from cooking on Yom Tov for a weekday (and for the second day of Yom Tov), how could cooking on Yom Tov for Shabbos be prohibited only Rabbinically?
There are two approaches to answer this question, and there is a significant practical difference between them. The first approach is that the question does not really begin: For while, indeed, cooking on Yom Tov for a weekday (and for the second day of Yom Tov) is prohibited Biblically, cooking on Yom Tov for Shabbos is actually permitted Biblically! The reason is that (as expressed in the Gemara),“[Biblically,] the needs of Shabbos [may be] done on Yom Tov.” The Rabbis were concerned, however, that if one were allowed to cook on Yom Tov for Shabbos one might also come to cook on Yom Tov for a weekday (or for the second day of Yom Tov). Therefore, they prohibited cooking on Yom Tov for Shabbos.
However, to provide for the essential need to cook/prepare food for Shabbos, they created the institution of Eiruv Tavshilin to allow one to cook/prepare on Yom Tov for Shabbos. By making an Eiruv Tavshilin, one realizes that there is no carte blanche allowance to cook on Yom Tov for Shabbos, so one will certainly realize that there is no carte blanche allowance to cook on Yom Tov for a weekday or for the second day of Yom Tov. As a result, one will not come to cook on Yom Tov for a weekday or for the second day of Yom Tov.
The second approach is that cooking on Yom Tov for Shabbos is, indeed, prohibited Biblically, just as is cooking on Yom Tov for a weekday or for the second day of Yom Tov. (I.e., Biblically, the needs of Shabbos may not be done on Yom Tov.) However, Biblically, if one cooked on Yom Tov for Shabbos one is not punished with lashes since if unexpected guests were to arrive, one would have, in effect, cooked on Yom Tov for that day of Yom Tov. Subsequently, if guests do not actually materialize, one would be permitted to eat the cooked food after Yom Tov. By extension, on a Biblical level, one would actually be permitted to cook extra food on Yom Tov “in case unexpected guests arrive later in the day,” even though one really intends to use the extra food for Shabbos should guests actually not materialize.
However, since guests are not actually expected, the Rabbis prohibited one from cooking extra food on Yom Tov with such intent. However, to provide for the essential need to cook/prepare food for Shabbos, they created the institution of Eiruv Tavshilin to allow one to cook/prepare on Yom Tov for Shabbos. By making an Eiruv Tavshilin, one realizes that there is no carte blanche allowance to cook on Yom Tov for Shabbos, so one will certainly realize that there is no carte blanche allowance to cook on Yom Tov for a weekday or for the second day of Yom Tov. As a result, one will not come to cook on Yom Tov for a weekday or for the second day of Yom Tov.
There is a significant practical difference between these two approaches. According to the second approach – which is based on the idea of cooking for potential unexpected guests arriving on Friday, one who made an Eiruv Tavshilin would be required to cook the food early enough on Friday for such unexpected guests to actually be able partake of the food on Friday. According to the first approach, however – which is not based on the idea of cooking for unexpected guests, but on the principle that, Biblically, the needs of Shabbos may be done on Yom Tov, no such requirement to complete the preparation early in the day applies. I.e., according to the second approach, one who made an Eiruv Tavshilin would be permitted to cook on Friday even shortly before Shabbos (but see note) even if there is no time for guests to come and partake of the food on Friday.
The Mishnah Berurah rules that one should follow the second approach and make sure to cook food early enough in the day to theoretically allow unexpected guests to partake from the cooked food on Friday. He writes, however, that when Friday is the second day of Yom Tov (such as on Rosh Hashanah, Sukkos in chutz la’aretz, Simchas Torah in chutz la’aretz, and the first days of Pesach in chutz la’aretz) – and, thus, Rabbinic in origin – if one was delayed in cooking and has a pressing need, one may act leniently and cook until sunset, even though the food will not be ready for unexpected guests on Friday.
He writes further that it is even possible to say that in cases of pressing need, even when Friday is the first day of Yom Tov (such as the seventh day of Pesach and Shavuos) – and, thus, Biblical in origin – one who made an Eiruv Tavshilin would be permitted to cook on Friday for Shabbos until sunset, even though the food will not be ready for unexpected guests.
He adds, though, that l’chatchilah (initially/preferably) one should certainly be careful and cook early enough to accommodate unexpected guests. In fact, the Poskim (halakhic authorities) cite the Levush who writes that to ensure that people not come to cook too late in the day on Friday of Yom Tov for Shabbos, there was a custom to accept Shabbos early on those Fridays. See also note.
Click here to access an article that presents many halakhot related to Eiruv Tavshilin – geared specifically for Shavuot.
How to do Eiruv Tavshilin:
A person should take matzah prepared for the Shabbos as well as a highly regarded cooked food, e.g., meat or fish. He should hand the matzah and the cooked food to another person who is not a member of his household and say (note: a person who is alone simply says the blessing and the prayers)
אַנִי מְזַכֶּה לְכָל מִי שֶׁרוֹצֶה לִזְכוֹת וְלִסְמוֹךְ עַל עֵירוּב זֶה
I hereby grant a share in this eruv to anyone who wishes to participate in it, and rely on it.
The person to whom the matzah and the cooked food was given raises them a handbreadth and then returns them to the person making the eruv. That person then says
בָּרוּךְ אַתָּה יְהֹוָה, אֱלֹהֵינוּ מֶלֶךְ הָעוֹלָם, אֲשֶׁר קִדְּשָׁנוּ בְּמִצְוֹתָיו, וְצִוָּנוּ עַל מִצְוַת עֵרוּב
Blessed are You, G‑d, our L‑rd, King of the universe, who has sanctified us with His commandments and commanded us concerning the mitzvah of eruv.
בְּדֵין יְהֵא שָרָא לָנָא לַאֲפוּיֵי וּלְבַשּׁוּלֵי וּלְאַטְמוּנֵי וּלְאַדְלוּקֵי שְׁרַגָּא וּלְתַקָּנָא וּלְמֶעֱבַד כָּל-צָרְכָנָא מִיּוֹמָא טָבָא לְשַׁבַּתָּא לָנָא וּלְכָל-יִשְׂרָאֵל הַדָּרִים בָּעִיר הַזֹּאת
Through this, it shall be permissible for us to bake, to cook, to cover [a dish and insulate it so that its heat will not dissipate], to kindle a light, and prepare and do on the festival all that is necessary for the Sabbath. This dispensation is granted] for us and for all Israelites who dwell in this city.
 Labors prohibited on Shabbos.
 Shulchan Aruch Orach Chaim 495:1.
 Included are even processes that are forbidden on Shabbos only mid’rabanan (Rabbinically), such as heating up in certain ways even food items that had been previously cooked.
 Rema O.C. 667:1.
 This halacha holds true even with regard to cooking on the first day of Rosh Hashanah for the second day of Rosh Hashanah (S.A. O.C. 503:1), even though the two days are considered as a yoma arcihta ([one] long day) for some purposes in halacha; see Mishnah Berurah 503:4, 606:1-2.
 In the diaspora – outside of EretzYisrael.
 Rambam, Hilchos Yom Tov 1:9; S.A. O.C. 503:1.
 Either on Rosh Hashanah or on the second day of Yom Tov in chutz la’aretz (or on the day after Pesach or Shavuos in Eretz Yisrael).
 Either on the last days of Pesach or on Shavuos – in chutz la’aretz.
 See Rema O.C. 257:8 with M.B. #49.
 Chachameinu zichronam livrachah – Our Sages, may their memories be blessed.
 And bake, et al.
 Similarly, if one makes an Eiruv Tavshilin on Wednesday, Erev Rosh Hashanah, one would be permitted to cook on Friday (the second day of Rosh Hashanah) for Shabbos; and if one makes an Eiruv Tavshilin on Wednesday, Erev Sukkos, one would be permitted to cook on Friday (the second day of Sukkos) for Shabbos (the first day of Chol Hamoed – the Intermediate days of Yom Tov) – in chutz la’aretz; and if one makes an Eiruv Tavshilin on Wednesday, Hoshana Rabbah, one would be permitted to cook on Friday (Simchas Torah) for Shabbos, the day after Simchas Torah – in chutz la’aretz; and if one makes an Eiruv Tavshilin on Thursday, the last day of Chol Hamoed Pesach, one would be permitted to cook on Friday, the seventh day of Pesach, for Shabbos (the eighth day of Pesach in chutz la’aretz, which is the day after Pesach in EretzYisrael).
 Gemara Beitzah 15b.
 O.C. 527:1.
 L’chatchilah, the food for Eiruv Tavshilin should be cooked on Erev Yom Tov specifically for the Eiruv Tavshilin. If one cooked the food earlier in the week or even purchased the food, one may still use that food for an Eiruv Tavshilin (M.B. 527:44 and Bi’ur Halacha 527:6 s.v. Adashim). See S.A. O.C. 527:14 and M.B. 527:43-45 regarding the permissibility of reusing the Eiruv Tavshilin from a prior Erev Yom Tov.
 See Rambam (Hilchos Yom Tov 6:1) who explains the origin of the term Eiruv Tavshilin differently. See also Ra’avad (ad loc.) and Aruch HaShulchan (O.C. 527:5).
 Pesachim 46b.
 See Rabbi Akiva Eiger (on Magen Avraham 302:6) for another application of this principle. Cf. Mishnah Berurah 302:17.
 See also Gemara Beitzah 15b.
 Gemara Pesachim 46b and Gemara Beitzah 21a. This concept is expressed in the Gemara as follows: “One who bakes on Yom Tov for a weekday does not receive lashes” [for performing melachah on Yom Tov.] The Rambam codifies this halacha in Hilchos Yom Tov 1:15 (see note that follows).
 Cf. Aruch HaShulchan O.C. 527:3.
 Kesef Mishnah, Hilchos Yom Tov 1:9; M.B. 527:3.
 This requirement presents somewhat of a challenge when Rosh Hashanah falls on Thursday and Friday, since davening (praying) is long and the seudah (meal) on Friday day ends very late.
 It should be noted that the Eiruv Tavshilin does not obviate any other halachic requirements relative to the “cooking” other than the actual “cooking” from Friday of Yom Tov to Shabbos. Accordingly, if one wants to keep the food warm on Shabbos, one must adhere to the standard halachic requirements that govern the placement of hot food on fire before Shabbos. For example, the food must be cooked before Shabbos (see S.A. O.C. 253:1 with Rema and Bi’ur Halacha s.v. V’nahagu for guidelines) or the fire – or the metal base/bowl of the crockpot – must be covered halachically (see S.A. ibid.), et al. See M.B. 527:3.
 M.B. 527:3 and Bi’ur Halacha 527:1 s.v. V’al Y’dei Eiruv.
 Eliyah Rabbah,Magen Avraham, and Mishnah Berurah.
 This is an additional factor that was not addressed in this article. The Gemara (Beitzah 2b) discusses a prohibition referred to as hachanah d’Rabbah (preparation [discussed] by the [Amora] Rabbah), which says that something that was prepared on Yom Tov may not be used on Shabbos that immediately follows it and vice versa. According to some Rishonim (early commentators) this prohibition is Biblical in origin. Accordingly, the question arise how one can cook on Yom Tov for Friday – even if one made an Eiruv Tavshilin – since the Eiruv cannot possibly allow a Biblical prohibition, as explained at the outset of the article. The answer is beyond the scope of this article. For further study, see Tosafos (ad. loc. s.v. V’hayah), Magen Avraham (introduction to chapter 527), Chasam Sofer (ad loc.), Aruch HaShulchan O.C. 527:1-3, and Megilas Sefer chapter 58.