Although the Torah prohibits performing melacha activity on Yom Tov, it permits preparing food. As the Torah states, Ach asher yei’ocheil lichol nefesh, hu livado yei’aseh lochem, However that which is eaten by all people, only it may be performed (Shemos 12:16). (We will soon discuss what the Torah means by saying that something is eaten by all people.) This verse permits cooking and other food preparation on Yom Tov, but does not appear to permit melacha for non-food purposes. If so, how can we carry machzorim and push baby carriages on Yom Tov in an area without an eiruv? Before answering this question, let us explore a Mishnah that is vital to this topic:
"Beis Shammai says, ‘One should not heat water for washing one’s feet on Yom Tov unless it is appropriate for drinking’, whereas Beis Hillel permit this. One may kindle a bonfire to warm oneself" (Beitzah 21b).
The Mishnah implies that both Beis Hillel and Beis Shammai forbid heating water on Yom Tov to bathe one’s entire body, and only dispute whether one may heat water to wash one’s feet. Beis Shammai rules that one may heat water on Yom Tov only for food purposes - to cook or to heat drinking water. In their opinion, if one needs to heat water on Yom Tov for washing, there is only one way: Prior to heating drinking or cooking water, one may place more water in the pot than one needs, planning to use the surplus hot water for washing (Tosafos, Beitzah 21b s.v. lo).
Why is this permitted? MARBEH BISHIURIM
This action is permitted because of a law called marbeh bishiurim, literally one increases the quantities, which means that while preparing food on Yom Tov, one may include a greater quantity with one’s action, provided no additional melacha act is performed. Based of this principle, one may place a large pot of water on the fire rather than a small one, since he is performing only one act of heating water. However, this is prohibited if one performs any additional melacha action. Similarly, one may not add extra water to a pot already on the fire unless he needs more water for cooking purposes.
Here is an example:
One may not bake on the first day of Yom Tov for the second. However, one may fill a pot with meat on the first day of Yom Tov even though he needs only one piece for the first day. Similarly, one may boil a large pot of water on the first day even though he needs only one cup of hot water. On the other hand, under most circumstances one may not bake more than one needs for the day (Gemara Beitzah 17a).
Why is baking different? The difference is that adding water or meat before putting the pot on the fire simply increases the quantity cooked, but does not increase the number of melacha acts. However, preparing extra bread entails shaping each loaf or roll separately, thus increasing the number of acts performed. HEATING WATER FOR WASHING
Similarly, Beis Shammai rules that one may only add water for washing to the drinking water before the water is placed on the fire, but not afterwards. They strictly forbid heating water exclusively for washing or bathing.
On the other hand, Beis Hillel permits heating water even on Yom Tov in order to wash one’s feet. Why may one do this? After all, this is not for food? MITOCH - EXPANDING PERMITTED MELACHOS
Beis Hillel’s rationale to permit this is the legal concept called mitoch shehutra litzorech, hutra nami shelo litzorech, which means that once the Torah has permitted any specific melacha to prepare food on Yom Tov, one may perform this melacha even for Yom Tov purposes that are not food related (Tosafos, Beitzah 12a s.v. hachi; cf. Rashi). This is why one may carry a machzor to shul on Yom Tov even in an area without an eruv. Since one may carry to prepare food, one may carry for a different Yom Tov purpose such as davening properly or taking a stroll, even though these activities have nothing to do with food.
The same reason permits building a fire on Yom Tov to warm oneself -- once the melacha of burning is permitted for cooking, it is permitted for other Yom Tov reasons. (There is one exception; one may not ignite a flame on Yom Tov but may only kindle from a preexisting flame. The reason for this prohibition is beyond the scope of this article.)
Similarly, Beis Hillel rules that one may heat water to wash one’s feet on Yom Tov. Although this use is not food related, once one may heat water for cooking, one may also heat water for a different Yom Tov purpose.
Why does Beis Shammai disagree with Beis Hillel and prohibit heating water for the purpose of having a bath? Because Beis Shammai rejects the concept of mitoch; in their opinion, one may not perform any melacha on Yom Tov unless it is food preparatory. Indeed, Beis Shammai prohibits carrying on Yom Tov except for food needs (Beitzah 12a). Our practice of carrying on Yom Tov for non-food needs is because we follow Beis Hillel’s acceptance of mitoch. HEATING BATH WATER
Despite Beis Hillel's acceptance of mitoch, they forbid heating water on Yom Tov to bathe one’s entire body (Mishnah Beitzah 21b). Why did Beis Hillel prohibit this activity if mitoch permits other Yom Tov activities? The answer to this question involves a fascinating dispute with major practical ramifications. RAMBAM’S REASON
Chazal prohibited bathing in hot water on Shabbos, even if the water was kept hot from before Shabbos, out of concern that bathhouse attendants might heat water on Shabbos, claiming that it was heated before Shabbos (Gemara Shabbos 40a). This prohibition is called the gezeiras merchatz, literally, the bathhouse prohibition, although it is not restricted to bathhouses, but includes almost all instances of bathing in hot water on Shabbos.
Similarly, the Mishnah (Shabbos 38b) describes how the residents of Teverya ran a cold water pipe through hot springs so that they could have hot bath water on Yom Tov. Nevertheless, the Sages prohibiting using this water for bathing since it was warmed on Yom Tov notwithstanding the fact that it was heated automatically.
The Rambam’s understanding is that Beis Hillel prohibits heating bath water on Yom Tov as an extension of the gezeiras merchatz even though no Torah violation can possibly result on Yom Tov (Rambam, Hilchos Yom Tov 1:16). In his opinion, Beis Hillel’s prohibition against heating bath water on Yom Tov is rabbinic, whereas according to Beis Shammai it is forbidden min hatorah. TOSAFOS’ REASON
Others dispute the Rambam’s conclusion, contending that heating bath water on Yom Tov is a violation min hatorah even according to Beis Hillel (Tosafos, Beitzah 21b s.v. lo). This approach requires an introduction. SHAVEH LICHOL NEFESH - EVERYONE APPRECIATES
Although the concept of mitoch sanctions non-food-preparatory melacha activity on Yom Tov, this authorization is limited to activities that most people appreciate, called shaveh lichol nefesh. However, mitoch does not sanction a benefit that only some people appreciate and others do not (Gemara Kesubos 7a).
Let me explain why this is so, and then provide some clarifying examples. When the Torah permitted melacha activity on Yom Tov, its words were: However that which is eaten by all
people, only it may be performed. By emphasizing by all (in Hebrew lichol), the Torah implied that only universally appreciated benefits are permitted. However, the Torah did not acquiesce to melacha activities not universally enjoyed.
A few examples will explain this concept. One may kindle fire on Yom Tov because that is how people cook. As I explained above, the concept of mitoch authorizes burning wood to heat the house since everyone appreciates being warm on a cold day (Mishnah Beitzah 21b). However, not everyone enjoys the aromatic fragrance of burning incense; it is not shaveh lichol nefesh. Therefore, one may not kindle incense on Yom Tov (Kesubos 7a).
Similarly, many contemporary poskim rule that smoking on Yom Tov desecrates the holiday (in addition to the other prohibitions violated for endangering one’s health and that of others) [see Shulchan Shelomoh, Refuah Vol. 2 pg. 221; Nishmas Avraham, Vol. 1 pg. 278]. They contend that most people today do not appreciate the pleasures of smoking, and therefore it is not shaveh lichol nefesh (see also Shaarei Teshuvah 511:5; Biyur Halacha 511:4). DOESN’T EVERYONE BATHE?
How does this compare to bathing on Yom Tov?
Until fairly recently, frequent bathing was uncommon. Therefore, Tosafos explains that warming bath water is not shaveh lichol nefesh and is therefore proscribed on Yom Tov min hatorah even according to Beis Hillel. As I explained above, the Rambam disagrees, maintaining that heating bath water is prohibited only midirabbanan as an extension of the gezeiras merchatz.
Thus, these authorities dispute whether heating bath water on Yom Tov is forbidden min hatorah or only midirabbanan. Is there any other practical difference between these two opinions? HEATING BATH WATER BEFORE YOM TOV
There is indeed a dispute between these two approaches: May one bathe on Yom Tov using water heated before Yom Tov? Let me explain.
Earlier, I mentioned the gezeiras merchatz banning bathing on Shabbos even with water heated before Shabbos, because of concern that the bathhouse attendants might desecrate Shabbos. Does the same concern exist on Yom Tov? The Ran (Beitzah 11a) explains that resolving this query depends on the dispute between Tosafos and the Rambam. According to Tosafos, heating bath water on Yom Tov violates Torah law; therefore, bathing on Yom Tov entails the same concerns that bathing does on Shabbos. Just as Chazal banned bathing on Shabbos, they banned bathing on Yom Tov (Tosafos, Shabbos 40a s.v. limotza’ei).
However, according to the Rambam, since heating bath water on Yom Tov is itself prohibited only midirabbanan, there is no reason to prohibit bathing on Yom Tov using water heated before Yom Tov. Indeed the Rif (Beitzah 11a) and other early authorities rule explicitly that one may bathe on Yom Tov using water heated from before Yom Tov.
Thus whether one may bathe on Yom Tov using water heated before Yom Tov is subject to dispute, the Rif and the Rambam permitting it, whereas Tosafos and others ban it. Since the Shulchan Aruch (511:2) rules like the Rif and the Rambam, a Sefardi may be lenient, whereas an Ashkenazi cannot be lenient since the Rama rules like Tosafos.
As I mentioned above, all authorities prohibit bathing on Yom Tov with water heated on Yom Tov, even if the water was heated automatically. WASHING PART AT A TIME
Although the Rama concludes that one may not bathe on Yom Tov even using water heated from before Yom Tov, halachic consensus permits washing one’s entire body this way provided one does not do so all at one time (Rashba, Ritva and Ran to Shabbos 40a; Elyah Rabbah 511:1; Mishnah Berurah 511:15, 18). This is called washing eiver eiver, one limb at a time. Thus, theoretically one may stand in a shower stall not beneath the water flow and place different parts of one’s body under the hot water one after another. Ashkenazim may not stand directly under the water flow because this washes most of one’s body at one time, but may splash water onto one’s body with one’s hands. According to the approach accepted by the Sefardim, one may stand directly under the flow of hot water.
However, all of this is permitted only if both of the following specific conditions are met that are not necessarily easy to fulfill:
1. One must be certain that one is using only water heated before Yom Tov. As I mentioned above, all authorities prohibit bathing in water heated on Yom Tov even if it was heated automatically.
Furthermore, hot water generally mixes with cold water before emerging from the faucet. If the hot water heats the cold water to yad soledes bo (usually assumed to be 113 degrees Fahrenheit), this involves heating bath water on Yom Tov, which is prohibited, and furthermore, one may not bathe in this water. Thus, one would need to guarantee that mixed water does not heat to this temperature.
Showering in a hotel or dormitory may be even more problematic as most of these facilities use a coil system that heats the water as you turn on the faucet. This would be prohibited according to all opinions because one is using water heated on Yom Tov, and would involve a Torah prohibition according to Tosafos since one is heating water to bathe one’s body.
2. Most North American household water heating systems operate with a boiler that automatically replaces hot water with cold as you use it. This means that when one bathes or showers, one is heating cold water not for the purposes of Yom Tov use. There are complicated rationale to permit the heating of the new water because it may be considered indirect (grama) heating of the water, which some permit on Yom Tov (Tosafos, Beitzah 22a s.v. vihamistapeik; Shaar HaTziyun 514:31; however cf. Magen Avraham 514:5 and Mishnah Berurah 514:20) and it is unintentional (eino miskavein) [see dispute between Magen Avraham 314:5 and Terumas HaDeshen; see also Ritva, Eruvin 88a].
In practice, each person should discuss with his rav whether and how to take a hot shower on Yom Tov. Whatever your decision, I wish you all a happy, kosher, and comfortable Yom Tov.
This Shiur is published also at Rabbi Kaganof's site