When It’s “Not Kosher” to Eat Kosher: The Halachos of the Fast Days

Fall 2023

With the impending arrival of Tzom Gedalya and Yom Kippur, now is a good time for a halachic review of the six ta’aneisim that are incorporated into the Jewish calendar.[1] In addition to the aforementioned, we fast on Asara B’Teves, Ta’anis Esther, Shiva Asar B’Tamuz and Tisha B’Av. The halachos apply to males from the age of thirteen and females from the age of twelve.[2]

Timing Is Everything: When the Fasts Begin and End

  • Yom Kippur[3] and Tisha B’Av[4] begin at sunset. If one wants to eat after the seudas hamafsekes, one should state before the end of the seudah that he wants to do so. Having this in mind before Birchas Hamazon is also enough.
  • The other fasts begin at alos hashachar (dawn).[5] On those days, if one wants to arise[6] before dawn and eat, he should go to sleep with the intention that he is not accepting the fast until dawn. Optimally, this should be stated, but having in mind to wake up and eat before dawn is also enough. If he did not intend to eat, then if he arose before the zman he may only drink until dawn.[7]
  • All fasts end at tzeis hakochavim.[8] Asara B’Teves that falls out on Erev Shabbos[9]also ends at tzeis hakochavim,[10] even in locations where it is summer. If someone fasts on a Friday for a yahrzeit and makes “early Shabbos,” he can break his fast after he makes Kiddush – even though it is before sunset. When taking upon himself to fast for the yahrzeit, he should stipulate this condition.[11]

Managing an Illness on Yom Kippur

  • If fasting poses a danger to one’s life, he must eat or drink as necessary.[12] Nonetheless, if a such a person is able to eat or drink “pachos mi’keshiur” – less than the amount for which one is chayav kareis[13] – and still avert the danger, he must only consume less than the shiur. An example of this is if one’s doctor says, “If you do not eat or drink for 25 hours, your life might be in danger, but if you periodically drink small amounts, you will remain hydrated enough to not be in danger.”
  • Pachos mi’keshiur involves two factors – the volume of what is consumed and the amount of time it takes to consume it.[14] For food, pachos mi’keshiur is less than a koseves hagasa, a type of large date eaten within the span of time of kedei achilas pras.[15] A practical way to eat pachos mi’keshiur is to fill a schnapps cup that holds 1 fl. oz. (29 ml)[16] with compacted bread (or another food item), and to consume it in its compacted form, waiting at least nine minutes before eating again. If waiting nine minutes still poses a danger, ask your rav about shorter time spans.[17] If it is determined that pachos mi’keshiur is insufficient and one’s life may still be in danger, the choleh must eat as much as necessary, even if it is more than pachos mi’keshiur and eaten in a shorter span than kedei achilas pras.
  • Regarding beverages, pachos mi’keshiur is less than a meloh lugmav, a cheekful of liquid every seven minutes. Unlike food, the shiur of liquids differs with each individual’s capacity to hold liquid. The larger the mouth, the larger the meloh lugmav. One can ascertain his or her exact meloh lugmav – before Yom Kippur – by filling his mouth completely with water, expelling it into a measuring cup or graduated cylinder and dividing the amount in half (to obtain the amount held by one cheek – meloh lugmav).[18]
  • An alternative to measuring one’s meloh lugmav, while ensuring one is drinking less than a shiur, is to drink from a 1 oz. schnapps cup[19] that is completely filled and to wait at least seven minutes before drinking again.[20] NOTE: Some schnapps cups sold as “1 fluid ounce (29 ml)” may in actuality hold a volume greater than 1 fl. oz. Measure the cup before Yom Kippur to ascertain its exact size. If this is not possible, fill it only 3/4 of the way. This is especially necessary for individuals with a small mouth. If this amount of liquid is insufficient, the choleh may drink this amount of liquid every four minutes or, when necessary, even every two minutes.
  • Food and drink shiurim are independent of one another and are not tallied as a single measurement, so one can simultaneously eat and drink pachos mi’keshiur of each.[21] If drinking is enough to alleviate any sakana, one may only drink, and not eat even pachos mi’keshiur.[22]
  • No bracha acharona is recited on pachos mi’keshiur. It is better to eat pachos mi’keshiur many times on Yom Kippur than to eat a large amount at one time. If one has a choice between staying home and completing the fast there, or going to shul and – due to the physical exertion – not being able to complete it, he should stay home and not go to shul.

Conduct and Considerations on Other Fast Days

  • One who is ill, even if the matter is not life-threatening, may eat or drink as normal.[23] This includes illnesses that are either non-life threatening or that may arise as a consequence of the ta’anis.[24]  Under normal conditions, a woman who is pregnant or nursing and in good health must fast on Yom Kippur and Tisha B’Av.[25] She is exempt on a Tisha B’Av that is a nidcheh[26] and on the other fast days (unless she is strong and capable of fasting).
  • A chosson and kallah during the week of shevah brachos must fast[27] but are exempt on Ta’anis Esther that is mukdam (i.e., moved back from Shabbos to Thursday, 11 Adar).
  • Anyone who is allowed to eat on a fast day should not indulge in delicacies or candy but rather eat basic foods.[28] One who is exempt from fasting does not have to make up the ta’anis on a different day.[29]
  • If one recites a bracha on food but before eating realizes it is a ta’anis, he should not eat the food[30] but rather say Baruch Sheim. If someone accidentally ate during a fast and then realized his error, he may not continue eating and must continue fasting.
  • On Yom Kippur and Tisha B’Av one may not rinse his mouth or brush his teeth. On the other fasts it is preferable to avoid this, unless there is great discomfort.

The Tefilos on Fast Days[31]

  • Avinu Malkeinu is recited at Shacharis and Mincha of fast days,[32] unless there is no Tachanun (i.e., it is not said on Tisha B’Av, Mincha of Friday Asara B’Teves, Mincha of non-nidcheh Ta’anis Esther and Shabbos Yom Kippur [except it is recited at Neilah]). Avinu Malkeinu is recited if a chosson is present or if there is a bris[33]or when davening in a beis avel – although Tachanun is omitted.
  • Only one who is fasting (even if he knows he will break his fast later) recites Aneinu at Mincha in Shema Koleinu. On Tisha B’Av, Nachem is recited at Mincha even if one already broke his fast. At Mincha, Sim Shalom is recited instead of Shalom Rav.

Additional Stringencies on Churban Bayis Fast Days

Besides Tisha B’Av, which has various hilchos aveilus,[34] Shiva Asar B’Tamuz and Asara B’Teves also commemorate different stages of the Churban Beis Hamikdash. Therefore, on these two fast days, some are zahir to observe certain halachos of the Nine Days. This includes not listening to music, not taking a haircut or shaving and not bathing for pleasure.[35] However, one may bathe l’kavod Shabbos when Asara B’Teves occurs on Friday.[36]

Accepting a Private Fast

If one fasts a private fast, he must “accept” the fast at Minchathe day before the fast.[37] The nusach is found in many siddurim at the end of Elokai Netzor of Mincha.[38] If he forgets, he can accept the fast after Mincha any time before sunset. For the Fast of BeHa”B, one can have in mind to accept the fast when responding Amen to the Mi Shebeirach recited on the Shabbos preceding BeHa”B.

In the zchus of our fasting, may our teshuva and tefilos be accepted and may the fasts be transformed to days of happiness and Yom Tov. [39]

[1] This article is based on the psak of Rabbi Moshe Heinemann shlit”a and focuses on various relevant halachos and addresses shailos that are frequently asked.

[2] On Yom Kippur, healthy children in the years leading up to their Bar/Bas Mitzva and capable of fasting should fast part of the day. Some say this also applies to other ta’aneisim (Tosfos Yom Hakipurim Yoma 82a Masnisin b’shyam Rama MePanu 111). However, the MB 550:5 says they do not fast at all but rather eat simple items. Also, the custom is to fast three complete fasts before one becomes Bar Mitzva, if there is no difficulty.

[3] One must start before sunset for Tosefes Yom Hakipurim.

[4] When it starts on Motzei Shabbos, the fast begins at sunset, however halachos of mourning (e.g., sitting low) begin at tzeis hakochavim. One may take a pill before the ta’anis that will help him fast. He may take it on Shabbos afternoon when Tisha B’Av is on Sunday, but should make the tablet sweet (e.g., put on honey on it) so he enjoys it on Shabbos and there is no hachana issue (see Kovetz Halachos – Bein Hametzarim 16:f19).                                                                                                                                                                                                                                                 

[5] There are various opinions on how to calculate the beginning and ending times of a fast which are beyond the scope of this discussion. Refer to your shul or local luach for exact times. Before the fast, under the conditions noted in the article, one may eat as usual even within a half hour of dawn (see Sefer Iyunim B’taanis Vol. 1 page 403 in the name of HaRav Elyashiv zt”l). For a discussion of other opinions, see Piskei Teshuvos O.C. 564:1.

[6] Following a sheenas kvah.

[7] See Rama O.C. 564:1.

[8] See footnote 5. When traveling by air, zmanim are determined by the position of the aircraft over the earth’s surface at any particular moment (e.g., when flying at 35,000 feet over Chicago, the zmanim of that city prevail.) Thus, a westbound flight will add hours to a fast.  Air travelers on fast days should take this halacha into account.

[9] For example, in 5784/2023 and 5785/2025.

[10] Kiddush is recited before eating.

[11] If someone already observed this yahrzeit fast on Friday until Tzeis Hakochavim, he should continue to do so. If in the first year it is not on Friday, he should stipulate that in future years it is Friday, he is only fasting until after Maariv – even if early. See Shulchan Aruch and Rama O.C. 249:4, and MB.

[12] If there is any safek whether one’s life is in danger and a halachic authority is not available, one must eat or drink as deemed necessary.

[13] The punishment for eating or drinking the defined amounton Yom Kippur.

[14] Shulchan Aruch O.C. 618:7-8 and Mishna Berurah. Pachos mi’keshiur is still prohibited for a healthy person (chatzi shiur asur min haTorah), however, there is no onesh kareis or malkos.

[15] See footnote 17.

[16] A koseves hagasa is larger than 1 fl. oz., but it is more practical to use 1 oz. plastic schnapps cups as they are readily available. [Although some “1 oz.” plastic schnapps cups are larger than 1 oz., they are still smaller than a koseves hagasa. In regards to using these cups for drinking, see below.]

[17]On Yom Kippur, we are machmir with the longest shiur of kedei achilas pras – nine minutes. If this is not enough for a choleh mesukan, it is four minutes. (Note that for bracha achronah during the year, this shiur is within the span of four minutes.)

[18] Rav Avraham Chaim Naeh in Sefer Shiurei Torah, Siman 3 footnote 33.

[19] Under normal circumstances this amount is certainly less than a meloh lugmav of an adult. Prepare the correct sized shnaps cups and time-measuring device before Yom Kippur.

[20] One who requires water to swallow medicine that is critical should use 1 oz. of an unpleasant tasting liquid (e.g., Pepto Bismol) every seven minutes. If this is not feasible and there is a possible sakana, use 1 oz. of water every seven minutes.

[21] Items such as yogurt or ices have a questionable food or drink status. Sugar dissolved in water is considered a beverage.

[22] The are many cases when the doctor says all the patient needs is hydration.

[23] In general, pachos mi’keshiur applies to Yom Kippur and not to the other fasts. Nonetheless, on other fasts if one only needs water in order to swallow a tablet, one should try to take it with less than a shiur of water. (See Kovetz Halachos BH”M (2:8).

[24] On Ta’anis Esther, one can be more lenient and stop fasting even for a bad headache or strong pain to the eyes.  However, in this case, (i.e., the fast was broken due to the leniency of Ta’anis Esther) one should make up the fast on a different day (see MB 686:5 in the name of Yeshuas Yaakov).

[25] A woman who has given birth within the past 30 days is not required to fast on Tisha B’Av.

[26] Moved to Sunday, the 10th of Av.

[27] The baalei bris (i.e., the mohel, father, and sandek) must fast, but they may eat after Mincha Gedola on a ta’anis nidcheh or mukdam.

[28] See MB 550:5.

[29] See footnote 24.

[30] Maharsham in Daas Torah 568 says this even for the day-only fasts. See however a different opinion in Shaarei Teshuva 568:1 in the name of the Birkei Yosef.

[31] Our discussion focuses on tefilos of day-only fasts, as recited even by individuals. Tefilos of the chazan/tzibur as well as those of Yom Kippur and Tisha B’Av are beyond the scope this discussion.

[32] Avinu Malkeinu can be recited without a minyan. Selichos can also be recited without a minyan, however, the Yud Gimmel Midos and the lead-up paragraphs of Kayl Erech Apayim and Kayl Melech Yosheiv should not be recited.

[33] In these cases, some end Selichos at Harachaman v’haslichos (Ishei Yisroel 44:12).

[34] On Yom Kippur and Tisha B’Av there are five inuyim (e.g., not wearing leather shoes). Yom Kippur has additional melacha prohibitions and Tisha B’Av has prohibitions due to mourning. These are beyond the scope of our discussion.

[35] See Kovetz Halachos, Bein Hameitzarim (2:4-5).

[36] MB 550:6.

[37] A chosson and kallah are not required to be mekabel their fast on the day before their wedding (MB 562:2). The same is true if someone regularly fasts on a particular day (e.g., every year on the yahrzeit of a parent).

[38] When accepting a private Sunday fast, recite the kabala at Minchaof Shabbos.

[39] Zechariah 7:19 and Selichos of Asara B’Teves.