Shabbat 50a ~ Cleanliness is next to Godliness

שבת נ, ב

דְּתַנְיָא: רוֹחֵץ אָדָם פָּנָיו יָדָיו וְרַגְלָיו בְּכׇל יוֹם בִּשְׁבִיל קוֹנוֹ, מִשּׁוּם שֶׁנֶּאֱמַר: ״כֹּל פָּעַל ה׳ לַמַּעֲנֵהוּ״

It was taught in a baraita: A person must wash his face, his hands, and his feet every day for the sake of his Maker, as it is stated: “The Lord has made everything for His own purpose” (Proverbs 16:4).

Cleanliness, it is said, is next to Godliness. Its is an odd phrase, suggesting that being clean is an attribute of divinity. Today’s passage in the Talmud suggests that cleanliness is a feature of a God-fearing person. Here is how Rashi, the eleventh-century exegete, explains it:

בשביל קונהו - לכבוד קונהו דכתיב (בראשית ט׳:ו׳) כי בצלם אלהים עשה וגו' ועוד דהרואה בריות נאות אומר ברוך שככה לו בעולמו

For the sake of his Maker: to honor his maker, as it is written (Gen. 9:6) “For he was made in the image of God.” In addition, when others see a clean person they will say “Blessed Be He who created this in His world.

As we will see, it wan’t just the face hands and feet that should be washed daily.

Early Christianity and its rejection of Hand washing

Washing and bathing rituals have been a part of Judaism since its inception, and it was over some of these rituals that the early Christians broke away from Judaism. Jesus spent much of his time among the ritually impure, which annoyed the rabbinate of the day. In the Gospel of Mark (7:1-23) we read that Jesus’ disciples ate bread with out having washed their hands. This was a remarkable rebellion, “For the Pharisees, and all the Jews do not eat unless they give their hands a ceremonial washing, holding to the tradition of the elders.” When criticized for this, Jesus belittled the practices and accused those who followed it of hypocracy: “Isaiah was right when he prophesied about you hypocrites; as it is written: “‘These people honor me with their lips, but their hearts are far from me. They worship me in vain; their teachings are merely human rules.’” From then on, Judaism and Christianity adopted very different attitudes towards personal hygiene and cleanliness.

“Jesus’ indifference to ritual purity accorded with what later became a wider Christian distrust or neglect of the body.”

— Katherine Ashenburg. The Dirt on Clean (North Point Press 2007) p 54.

Clean Body, Clean Clothes

Elsewhere, there Talmud outlines the importance of bathing in a discussion about vows:

נדרים דף עט, א - פא, א 

ואלו נדרים שהוא מפר, דברים שיש בהן ענוי נפש: אם ארחץ ואם לא ארחץ ...אלא דאמרה הנאת רחיצה עלי לעולם אם ארחץ היום, ורבי יוסי סבר: ניוול דחד יומא לא שמיה ניוול

מעיין של בני העיר, חייהן וחיי אחרים - חייהן קודמין לחיי אחרים, בהמתם ובהמת אחרים  בהמתם קודמת לבהמת אחרים, כביסתן וכביסת אחרים - כביסתן קודמת לכביסת אחרים, חיי אחרים וכביסתן - חיי אחרים קודמין לכביסתן, רבי יוסי אומר: כביסתן קודמת לחיי אחרים

כביסה אלימא לר' יוסי, דאמר שמואל: האי ערבוביתא דרישא מתיא לידי עוירא, ערבוביתא דמאני מתיא לידי שעמומיתא, ערבוביתא דגופא מתיא לידי שיחני וכיבי

These are the vows [made by a wife] that a husband may revoke: matters that involve self-afflction. For example [a wife made a vow] "If I bathe and if I do not bathe..."

What could this mean? She said The pleasure of bathing is forbidden to me forever if I bathe today. And Rabbi Yossi believes that not bathing for one day is not called repugnance...

If a spring belonged to townspeople, [but it does not supply the needs of everyone, whose needs take precedence?] When it is a question of their own lives or the lives of strangers, their own lives take precedence;  the lives of their cattle or the cattle of strangers - their cattle take precedence over those of strangers; their laundering or that of strangers - their laundering takes precedence over that of strangers. But if the choice lies between the lives of strangers and their own laundering, the lives of the strangers take precedence over their own laundering. R. Yossi ruled: Their laundering takes precedence over the lives of strangers...

[The discomfort of not laundering clothes is greater than that of not bathing] according to Rabbi Yossi, as Shmuel taught: filth on the head leads to blindness, dirty clothes leads to dementia, not bathing leads to boils and sores...

This passage seeks to understand a Mishnah which taught that a husband may annul his wife's vow if it would interfere with her bathing regime and hence cause her to become, well, smelly and unattractive.  In contrast to this, Rabbi Yossi (a student of Rabbi Akivah and who lived in Israel in the second century C.E.) taught that this vow cannot be annulled, since he understands that it only prevents her from bathing for a single day - and this brief abstinence does not cause her to become repugnant in her husband's eyes.  The analysis is completed when it is discovered that Rabbi Yossi, while not seeming to be bothered by a lack of one day of bathing, was indeed very bothered by a lack of clean laundry.  How bothered? Well, if it's your water and you only have enough to clean your own laundry or to give an outsider a life sustaining drink, guess who is going to be wearing some clean clothes! Rabbi Yossi was so bothered by dirty clothes that he valued them over life itself (so long as that life was not your own). It seems rather odd, does it not, for Rabbi Yossi to allow a wife to do without bathing for a day and yet hold clean clothing to be really important? To answer this, we need to dive in to the history of bathing.

Jewish, Roman and Early Christian Bathing Habits

The Talmud is replete with statements that emphasize the importance of daily bathing.  A scholar (תלמיד חכם) is forbidden to live in a town that does not have at least one bathhouse, and Hillel the Elder taught his students that going to wash in the bathhouse was a mitzvah, since there was a responsibility to care for the human body, created as it was in the very image of God. Hillel seems to have left a cleanliness legacy in his family: his grandson, Rabban Gamliel (who lived in the early part of the first century CE.) was so in need of bathing that he allowed himself to wash on the first night after his wife died - an act that was forbidden.

In the Jerusalem Talmud, the precedent of Rabban Gamliel is further analyzed. When a rabbi developed boils during his period of mourning (which the Talmud assumes was due to a lack of washing) a certain Rabbi Yassa allowed him to wash immediately - "for otherwise he could die." Rabbi Yassa extended his ruling to allow bathing on (wait for it...) Tisha Be'Av and Yom Kippur - so long as the bathing was to alleviate discomfort rather than for pleasure. The famous Greek physician Hippocrates, (died c. 370 BC) wrote about the healing power of warm (and very cold) baths.  But as Katherine Ashenburg wrote in The Dirt on Clean, her definitive (and very readable) history of bathing, "...while the Greeks appreciated water...the Romans adored it."  The Roman desire of cleanliness and their culture of bathing is of course well known to anyone who has visited a Roman ruin in Israel, Italy or elsewhere.

The focus on bathing seems to have changed with the fall of the Roman empire and the rise of Christianity. Ashenburg explains that since the first Christians were Jews, a way of distinguishing themselves - as we have noted - was to ignore the Jewish laws of ritual purity, which involved so much hand washing and body dipping.  Although ritual purity is not the same as cleanliness, the two became linked, and with the opposition to the Jewish rules of ritual cleanliness, there rose a Christian opposition to bathing.  In the middle ages, some monastic orders allowed only three baths a year, "but monks whose holiness trumped cleanliness could decline any or all baths." What few bathhouses there were in medieval Europe were closed during the years of the Great Plague, since the best science of the day taught that heat and water created openings on the skin, through which the plague would enter.  "Sadly, the best medical advice of the day probably doomed many people, for the dirtier people were, the more likely they were to harbor Pulex irritants, the flea now believed to have carried the plague bacillus from rats to humans."

“Eilizabeth I of England bathed once a month, as she said, “whether I need it or not.” But the seventeenth century raised the bar: it was spectacularly, even defiantly dirty. Elizabeth’s successor, James I, reportedly washed only his fingers, The body odor of Henri IV of France (1553-1610) was notorious, as was that of this son Louis XIII. He boasted, “I take after my father, I smell of armpits”.”

— Ashenburg. The Dirt on Clean. p99.

Clean Linens and Rabbi Yossi

While washing the body was generally avoided in seventeenth century Europe, clean clothes were most certainly demanded, especially among the middle and upper classes.  "Clean linen" writes Ashenburg, "was not a substitute for washing the body with water - it was better than that, safer, more reliable and based on scientific principles." And here perhaps is an echo of the position of Rabbi Yossi in Nedarim.  To be clear: Rabbi Yossi was not arguing that bathing was not important - rather he argued about the length of time a person could forgo a bath and not become "repulsive" to a spouse.  But his emphasis on the need for laundered and clean clothes is striking.  As we noted, the Talmud (Nedarim 81a) relates Rabbi Yossi's concerns to a teaching of the physician Shmuel: Filth on the head leads to blindness, dirty clothes leads to dementia, and not bathing leads to boils and sores..." According to Rabbenu Nissim, (a fourteenth century commentator known by his acronym as the Ran, but pronounced Run), the first and third of these conditions may be cured - but not the dementia caused by dirty clothes. That's why Rabbi Yossi claimed that the water needed to do the laundry was so important.  Here's the text of the Ran:

כשגופו מזוהם שאינו רוחץ תמיד מביאו לידי שיחנא וכיבי אבעבועות המכאיבות ולאלו יש רפואות אבל שעמום קשה מהן אלמא כביסה אלימא מרחיצה

Bathing and Healing

In a 2002 a review of the history of spa therapies was published in Annals of the Rheumatic Diseases,  the authors noted that several randomised controlled trials had studied the effects of spa therapy in rheumatoid arthritis and osteoarthritis but that "definite judgment about its efficacy is impossible because of methodological flaws in these studies." However, "...overall, the results showed positive effects lasting for three to nine months. Recently, a randomised controlled trial has shown that spa therapy is clearly effective in ankylosing spondylitis. Two intervention groups followed a three week course of spa therapy at two different spa resorts, and were compared with a control group who stayed at home and continued standard treatment consisting of anti-inflammatory drugs and weekly group physical therapy. Significant improvements in function, pain, global wellbeing, and morning stiffness were found for both intervention groups until nine months after spa therapy." 

Bathing - and clean clothes - are social customs that have changed and changed again over time. We  know of no evidence to support Rabbi Yossi's link between dementia and clean clothes, but at other times and in other cultures clean clothes were indeed valued far beyond a clean body.  And today, in the midst of the COVID pandemic, bathing, laundry and above all hand-washing still seem like rather good ideas.

Avraham HaCohen. Millel LeAvraham. Bnei Brak 1980. 145.

Furthermore, during the enormous [influenza] pandemic after the First World War which killed many from across all nations, very few Jews died…There are a number of practices over the generations that prove that our Torah is a Torah of Life. Even now, during the cholera, may we be spared, the Ministry of Health has declared that everyone must wash their hands prior to eating, and must wash all fruit and edibles very well. Blessed be He who has chosen us and given us the Torah of Truth. Thus is what is meant when they said how great is the Torah which instills life into those who follow it both in this world and how much more in the world to come, the Eternal World!

[A partial repost from here.]

Shabbat 47a ~ Electricity on Shabbat

In a discussion on the permissibility of assembling various items on Shabbat, there is this:

הַמַּחֲזִיר קְנֵה מְנוֹרָה בְּשַׁבָּת — חַיָּיב חַטָּאת. קְנֵה סַיָּידִין — לֹא יַחֲזִיר, וְאִם הֶחֱזִיר — פָּטוּר, אֲבָל אָסוּר

One who reassembles the branch of a disassembled candelabrum on Shabbat is liable to bring a sin-offering. With regard to the plasterer’s pole, which has several component parts, one may not reassemble it ab initio, and if he reassembled it, he is exempt from bringing a sin-offering, although it is prohibited.

It is from this rather uninteresting remark that a major modern prohibition was derived. The Chazon Ish, Rabbi Avrohom Yishaya Karelitz (1874-1953) was the undisputed leading Haredi rabbi of his period in Israel, where he lived from 1933 until his death. He gave an entirely new interpretation to this passage and insisted that it was the source for the prohibition against turning electrical devices on and off on Shabbat.

Since its widespread use, the rabbis had that turning on say an incandescent light bulb was prohibited on Shabbat because it violated the ban against burning (because the metal in the bulb would become white hot) or cooking (because the metal in the bulb would become soft under the heat). These certainly were considerations, but the Chazon Ish added a new twist on an old ban. Here it is in the original:

חזון איש - אורח חיים - מועד, סימן נ

In addition (to the prohibitions of cooking or burning) there is also the probation against fixing an object (מתקן כלי), since by turning on the switch it allows the circuit to become complete and the electric current can then flow. This is close to the prohibition against building which comes from the Torah, for he is fixing an object…

The source text for this ruling of the Chazon Ish is in today’s page of Talmud - the one with which we opened. Here is his explanation of the Talmud: 

In Shabbat 47a we read “With regard to the plasterer’s pole, which has several component parts, one may not reassemble it. If nevertheless he did reassemble it, he is exempt from bringing a sin-offering, although it is prohibited.” It would appear that the ruling regarding the plasterer’s pole is comparable to its ruling regarding the pole of a lamp as appears in the prior clause, in that we are discussing attaching the pieces tightly, and nonetheless in the case of a plasterer’s pole one is exempt from the biblical violation of Shabbat. The reason is that the lamp is primarily used assembled, and when one disassembles it, it is not in order to use it but rather for a different purpose. However, the plasterer’s pole has two usable forms: to reach a low place a long pole is unsuitable, and to reach a high place a short pole is unsuitable. Thus, when one lengthens it temporarily, even if it is tightly joined, it is like stacking one tool on another to reach a high place and it is never really designated a “long pole.”

Here is how Dan Margulis, rabbi of the Riverdale Minyan explained the thinking of the Chazon Ish in his recent article on this topic published on The Lehrhaus:

As the Hazon Ish explains the Tosefta’s cases, it is prohibited to build a new tool or device on Shabbat because of “building.” Tools constructed of component parts which are then joined tightly are problematic for this reason. However, if the tool has two useful states—e.g. a plasterer’s pole which is used in both a long and short configuration—then no biblical violation is ever violated, since although the pieces are tightly joined, the tool always exists in an incomplete state of sometimes-short-sometimes-long.

In order to claim that the use of electricity on Shabbat constitutes a biblical violation, the Hazon Ish argues that (a) the joining of parts involved is considered “tight,” (b) that any electrical device is more similar to the lamp-pole (with one useful state) than the plasterer’s pole (with two interchangeable useful states), and, most importantly, (c) that this is an apt analogy to use as the basis for an entire model for the use of electricity in general…

The Hazon Ish claims that any electrical device is considered by Halakhah to be broken when the current is not flowing within it, since the “object” does not have the “form” necessary to be useful in the way in which it is normally used. When the electric current is connected to the “object” and its electrical components are activated, it attains the “form” necessary to become useful. In the case of the plasterer’s pole, the two lengths of wood which comprise the long handle are both objects. According to the Hazon Ish joining two objects together is a less intrinsic change than joining together an object and the electrical power which changes its form. Thus, the act of causing the current to flow through the electrical components constitutes an act of building the device itself—transforming it from a form in which it was unusable to a form in which it is usable…

And so, as Rabbi Margulis concludes, the Chazon Ish ruled that “enabling electrical current to flow through an electrical device currently powered down constituted building or repairing that device from a useless or unusable state to a useful one.” What it also important to note is that using a device “which remains on, even though its normal use involves opening and closing thousands of circuits is not the sort of boneh the Hazon Ish was concerned with.” This is important since it informs other rulings about using computers or smart watches on Shabbat that have been turned on earlier.

The operation of any electronic device involves the opening and closing of many circuits in the thousands or millions of transistors needed to complete even basic computational functions. However, since a transistor performs calculations and stores data with both the “on” and “off” states playing necessary and useful roles, the Hazon Ish would concede within his own paradigm that the operation of these electronics cannot possibly constitute a biblical violation of Shabbat, since their function is closer to the more lenient case of the plasterer’s pole than the more stringent case of the lamp-pole. Further, since the device as a whole remains on the entire time, and is never “dead” or without its tzurah, there can be no biblical violation of boneh as the Hazon Ish described in the normal use of an electronic device which remains on.

And all this from the simple observation of the Talmud about some guy plastering.

Shabbat 34b ~ Sunrise, Sunset

Today’s page of Talmud deals with the topic of dusk or twilight, known in Hebrew as Bein Hashmashot. It is not quite night, and certainly still not day, so what may and may not be done during that period on Friday afternoon? Has Shabbat begun, in which case work is prohibited, or is it still technically Friday, in which case work is permitted?

שבת לד,ב

תָּנוּ רַבָּנַן: בֵּין הַשְּׁמָשׁוֹת סָפֵק מִן הַיּוֹם וּמִן הַלַּיְלָה, סָפֵק כּוּלּוֹ מִן הַיּוֹם, סָפֵק כּוּלּוֹ מִן הַלַּיְלָה — מְטִילִין אוֹתוֹ לְחוֹמֶר שְׁנֵי יָמִים. 

The Sages taught a baraita which discusses the range of problems that arise with regard to the twilight period. Twilight is a period of uncertainty. It is uncertain whether it consists of both day and night, it is uncertain whether it is completely day, and it is uncertain whether it is completely night. Therefore, the Sages impose the stringencies of both days upon it. If there is a stringency that applies on either of the days, one is obligated to adhere to it during the twilight period.

So far so good. But when does this liminal period start and end? There are at lest three opinions:

מִשֶּׁתִּשְׁקַע הַחַמָּה כָּל זְמַן שֶׁפְּנֵי מִזְרָח מַאֲדִימִין. הִכְסִיף הַתַּחְתּוֹן וְלֹא הִכְסִיף הָעֶלְיוֹן — בֵּין הַשְּׁמָשׁוֹת. הִכְסִיף הָעֶלְיוֹן וְהִשְׁוָה לַתַּחְתּוֹן — זֶהוּ לַיְלָה, דִּבְרֵי רַבִּי יְהוּדָה.

רַבִּי נְחֶמְיָה אוֹמֵר: כְּדֵי שֶׁיְּהַלֵּךְ אָדָם מִשֶּׁתִּשְׁקַע הַחַמָּה חֲצִי מִיל

רַבִּי יוֹסִי אוֹמֵר: בֵּין הַשְּׁמָשׁוֹת כְּהֶרֶף עַיִן, זֶה נִכְנָס וְזֶה יוֹצֵא, וְאִי אֶפְשָׁר לַעֲמוֹד עָלָיו

From when the sun sets, as long as the eastern face of the sky is reddened by the light of the sun. If the lower segment of the sky has lost its color, and the upper segment has not yet lost its color, that is the twilight period. If the upper segment has lost its color, and its color equals that of the lower one, it is night; this is the statement of Rabbi Yehuda.

Rabbi Nechemya says: The duration of the twilight period is the time it takes for a person to walk half a mil after the sun sets.

Rabbi Yossi says: Twilight does not last for a quantifiable period of time; rather, it is like the blink of an eye: This, night, enters and that, day, leaves, and it is impossible to calculate it due to its brevity.

We have previously met the opinion of Rabbi Yossi on the very first page of the Talmud. It deals with the obligation to recite three passages from the Torah called the shemah. These must be recited “when you lie down in the evening and when you stand in the morning” (Deuteronomy 6:7). The rabbis debate when these times might be, and link them several events, including sunrise and sunset. These two solar events are relatively easy to agree upon. But what about that period right after sunset and before nightfall, which we call dusk? Or that period right before sunrise and after the night, which we call dawn? Defining these periods of time are much more subjective, since they depend on shades of light, rather than the position of the sun on the horizon.

As we have seen, there are various opinions as to when these liminal periods start and end, including that of Rabbi Yossi, whose underscored the subjectivity of the whole enterprise.

Civil, Nautical, and Astronomical dusk

Jews were not the only ones that had to define the parameters of dusk and dawn. So too did astronomers. Their most widely accepted definitions depend on the position of the center of the sun below the horizon as seen at sea level, as shown below.

Here are the definitions, according to the US National Weather Service.

1. Civil Twilight:  

This period begins in the morning, or ends in the evening, when the geometric center of the sun is 6 degrees below the horizon. Under these conditions (and absent absent fog or other restrictions,) the brightest stars and planets can be seen, the horizon and terrestrial objects can be discerned, and in many cases, artificial lighting is not needed.

2. Nautical Twilight:

This begins in the morning, or ends in the evening, when the geometric center of the sun is 12 degrees below the horizon.  In general, the term nautical twilight refers to sailors being able to take reliable readings via well known stars because the horizon is still visible, even under moonless conditions.  Absent fog or other restrictions, outlines of terrestrial objects may still be discernible, but detailed outdoor activities are likely curtailed without artificial illumination.

3. Astronomical Twilight:

This begins in the morning, or ends in the evening, when the geometric center of the sun is 18 degrees below the horizon.  During astronomical twilight, sky illumination is so faint that most casual observers would regard the sky as fully dark, especially under urban or suburban light pollution.  Under astronomical twilight, the horizon is not discernible and moderately faint stars or planets can be observed with the naked eye under a non light polluted sky. Point light sources such as stars and planets can be readily studied by astronomers under astronomical twilight.

What can you see at dusk?

What you could see during Bein Hashmashot will depend on where you happen to live. Back in 1952 a very determined group of astronomers demonstrated this with a series of illumination measurements at dusk. One was taken on Sacramento Peak New Mexico (altitude 2,800m) and the second “in the country in Maryland near sea level” (altitude 30m). “It was the impression of the observers that owing to the clearness of the mountain air the overhead and eastern portions of the sky during evening twilight were much darker relative to the western sky at Sacramento Peak than in Maryland.”

Zenith sky brightness values at Sacramento Peak New Mexico. From Koomen M.J. et al. Measurements of the Brightness of the Twilight Sky. Journal of the Optical Society of America 1952: 42 (5); 353-356.

Another way of looking at this is by the change in brightness as we move from civil, through nautical and then astronomical twilight until we finally arrive at night.

Smoothed illuminance E (in lux) on a horizontal surface as a function of the zenith distance of the sun. From Grzegorz V. Rozenberg. Twilight: A Study in Atmospheric Optics. Springer Science, New York 1966. 18.

Here is a description of what is happening, by the Russian physicist Georgii Vladimirovich Rosenberg, who was the Deputy Director of the Institute of Physics of the Atmosphere, (a part of the “Academy of Sciences of the USSR”). It explains why the sky is darker at higher altitudes and cleaner air:

So yes, the more pollution, the more light scattering and the more you can see at twilight as the sun’s setting rays are refracted through the atmosphere. It’s counterintuitive. But hey, it’s science.

the long jewish tradition of being late for Shabbat

בבא קמא דף לב עמוד א 

אמר מר ומודה איסי בע"ש בין השמשות שהוא פטור מפני שרץ ברשות

The Master said above: And Isi concedes with regard to one who runs and causes damage at twilight on the eve of Shabbat that he is exempt, because he is running with permission. 

According to the talmudic sage Isi, if a person is running and as a result of his haste causes damage to others, he is exempt from damages if this happens at twilight on a Friday afternoon. Being late for Shabbat was clearly so common an occurrence that the rabbis had to make legal allowances for the late comers. But why were these people running? Not to compete a mundane activity, but to welcome the Shabbat Bride herself, as the Talmud continues:

בע"ש מאי ברשות איכא  כדר' חנינא דאמר ר' חנינא בואו ונצא לקראת כלה מלכתא ואמרי לה לקראת שבת כלה מלכתא רבי ינאי מתעטף וקאי ואמר בואי כלה בואי כלה

The Gemara asks: What is the reason that running at twilight on the eve of Shabbat is considered to be with permission? The Gemara answers: It is like that which Rabbi Chanina would say, as Rabbi Chaninah would say at twilight on the eve of Shabbat: “Come and let us go out to greet the bride, the queen. And some say that this is what he would say: Come and let us go out to greet Shabbat, the bride, the queen. Rabbi Yannai would wrap himself in his tallit and stand at the eve of Shabbat at twilight, saying: Come, bride; come, bride. 

From the Passover Archives ~ The Chemistry of Chametz

It is Pesach (Passover) tomorrow night, so let’s review the chemistry of unleavened bread, called chametz.

מנחות ע,ב

מנא הני מילי אמר ריש לקיש אתיא לחם לחם ממצה כתיב הכא (במדבר טו, יט) והיה באכלכם מלחם הארץ וכתיב התם (דברים טז, ג) לחם עוני 

והתם גופה מנלן אמר ריש לקיש וכן תנא דבי ר' ישמעאל וכן תנא דבי ר' אליעזר בן יעקב אמר קרא (דברים טז, ג) לא תאכל עליו חמץ שבעת ימים תאכל עליו מצות לחם עוני דברים הבאים לידי חימוץ אדם יוצא בהן ידי חובתו בפסח יצאו אלו שאין באין לידי חימוץ אלא לידי סירחון

How do we know that matzah must be made from one of five species of grain [wheat, barley, oats spelt and rye]?  Reish Lakish said, and likewise a Sage of the school of Rabbi Yishmael taught, and likewise a Sage of the school of Rabbi Eliezer ben Ya’akov taught, that the verse states: “You shall eat no leavened bread with it; seven days you shall eat with it matzah, the bread of affliction” (Deuteronomy 16:3). This verse indicates that only with regard to substances that will come to a state of leavening does a person fulfill his obligation to eat matzah by eating them on Passover, provided that he prevents them from becoming leavened. This serves to exclude these foods, i.e., rice, millet, and similar grains, which, even if flour is prepared from them and water is added to their flour, do not come to a state of leavening but to a state of decay [sirḥon].

The important question we need to answer here is whether there is something fundamentally different about rice when compared to the five grain species that can become chametz. And is there any scientific support to the claim that rice spoils sooner than it ferments?

The Chemistry of bread making

To get at the answers we need to remind ourselves how plants make and consume starch. They take carbon dioxide from the atmosphere and water from the soil, and using the energy contained in sunlight (and the magic of chlorophyll) convert the two into a large sugar molecule we call starch. Plants use this starch to store and provide them with energy.

If you grind up wheat (or many other species of grain) you make flour which contains loads of starch. In addition to starch, flour contains proteins and enzymes which become important when the flour is mixed with water. Without going down a rabbit-hole of detail, here in general is what happens. First, an enzyme called beta-amylase breaks the large starch molecule down into a smaller molecule called maltose which is made up of two molecules of glucose. Another enzyme, maltase, breaks down each molecule of maltose into two molecules of glucose which is then broken down further to provide the plant with energy. Here is what it looks like:

From Lloyd, James R and Kötting, Oliver (July 2016) Starch Biosynthesis and Degradation in Plants. John Wiley & Sons, Ltd: Chichester.

If you add some yeast into that mix, a chemical reaction called fermentation occurs. Yeast, which is a fungus, consumes glucose and turns it into carbon dioxide and ethanol, which is an alcohol.

As the flour and water and yeast all mix together, two proteins in the flour called gliadin and glutenin (which are glutens) give the dough mixture its characteristic body, which strengthens the more it is mixed. The dough traps the carbon dioxide that is given off by the yeast cells, which causes the bread to rise. And that gives us the leavened bread we call chametz.

Of course when matzah is made, we do not add yeast to the dough. But there are yeast particles in the air and these will inevitably land on the dough where they will act in the same way, consuming glucose and creating carbon dioxide and alcohol. This process is much slower than when yeast is added when bread is made, but the plain dough will rise a little as a result.

The differences between grains and rice

Resh Lakish (together with those sages of the schools of Rabbi Yishmael and Rabbi Eliezer ben Ya’akov) claim that unlike grains, rice does not ferment when water is added to it. Instead it spoils. That’s why it may be eaten on Passover (unless of course you are an Ashkenazi Jew, in which case you still can’t eat it, but for another reason we’re not going to get into). Is this in fact the case?

I know next to nothing about plant biology. But Dr Angus Murphy does. He is Professor and Chair of the Department of Plant Science at the University of Maryland, and wrote the textbook on plant physiology. Dr. Murphy was kind enough to have a long chat with me over the phone and he agreed with the suggestion that grains and rice do very different things when mixed with water. The wheat seed is surrounded by the endosperm, which is itself covered by the aluerone layer. This aleurone is rich in amylase which as you recall is needed to breakdown starch into glucose (which is eaten by yeast which releases carbon dioxide and alcohol which causes the dough to rise…) However (most species of) rice do not contain this aleurone layer. So they have very little amylase, which means that it takes them a much longer time to convert starch into glucose. In fact it takes so long that by the time there is enough yeast in the dough for it to start to rise, bacteria in the air will have colonized the mixture and started breaking down the proteins in the dough. And that protein breakdown is what makes the mixture spoil, and which is what the Talmud calls סירחון. To conclude, Professor Murphy thought that the Talmud’s description of the difference between grain and rice was firmly based in plant biology.

The fine print and the final verdict

Distribution of variou types of amylases in rice grains. (Beta-Amylase activity was expressed in terms of maltose mg liberated in 3 min at 30°C by 1 g of ground rice samples.) From Ryu Shinke, Hiroshi Nishira & Narataro Mugibayashi. Types of Amylases in Rice Grains. Agricultural and Biological Chemistry 1973; 37:10, 2437-2438

Of course things are a little more complicated than that. (They always are.) Different kinds of wheat flour contain different amounts of amylase. Fine bleached white flour contains less amylase than say whole wheat flour, because the aleurone layer in whole wheat flour has not been broken down. Similarly, different species of rice contain different amounts of amylase, so that while standard white rice has very little, brown rice has considerably more. During talmudic times, the wheat flour would have been far less processed than any of the flour we would use today. As a result it would contain more amylase, and would have risen faster than would today’s four-water mixtures.

But as a rule of thumb, the Talmud is, biochemically speaking, spot on. When mixed with water, the five species of grain from which matzah may be made do undergo fermentation even without the addition of yeast, while rice will spoil long before the fermentation process becomes noticeable.

Talmudology wishes all its readers a very happy, and a very healthy Passover (or Easter).