Shiurim
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"Who hath measured the waters in the hollow of his hand, and meted out heaven with the span, and comprehended the dust of the earth in a measure, and weighed the mountains in scales, and the hills in a balance?" (Isa 40:12)
Introduction
The Written Law (Torah, תורה שבכתב) enumerates many positive and negative commandments concerning food. For example, we are commanded to eat matsah on Passover (Ex 12:18). Likewise, we are forbidden from eating meat from non-kosher animals (Lev 11:4). However, the written Torah does not tell us what amount of food is required or forbidden -- or indeed, whether there is even a specific amount. The Oral Law (תורה שבעל-פה) does establish specific measurements which are used to determine whether or not one has fulfilled a positive commandment, or is Heaven forbid liable for punishment for having transgressed a negative commandment. These measurements, called shiurim (שיעורים) are the topic of this paper.
For example: in general, and regarding the most common forbidden foods, one is liable for punishment only after consuming the amount called a kazzayit (כזית) (Laws of Forbidden Foods 14:1). Nevertheless, consuming any amount of such food is forbidden. Likewise, one may not say a blessing after eating unless one has eaten at least this amount. One who did not eat a sufficient quantity of food, but nevertheless said an after-blessing transgresses the Biblical prohibition of taking God's name in vain (Laws of Blessings 1:15)! It is clearly important to know what these measurements are in modern, practical terms.
The question addressed in this paper is, "What are these measurements in modern terms?". To do this, it is necessary to sift through Jewish legal (halachic) sources ranging from the Talmud through modern times. The specific measurements we will seek to clarify are the "reviit" (רביעית, quarter-log), the "kabbeytsah" (כביצה, egg's-bulk) and the "kazzayit" (כזית, olive's-bulk).
Talmudic sources
- Berachot 38b (ד"ה: רבי יוחנן היכי מברך על זית מליח): the Sages ask how R' Yohanan could make a final blessing after having eaten only one olive? The question is clarified by mentioning that once the seed of the olive is removed, the remaining food will no longer contain a kazzayit. This clearly indicates that - at least in this instance, our Sages say that a kazzayit is an actual olive's bulk. The discussion continues, and states at the top of 39a (זית שאמרו לא קטן ולא גדול אלא בינוני) that the "olive" mentioned in halacha is neither a small nor a large one, but rather an "average" one. The Mishnah Kelim 17:8 states the same.
- Berachot 41a (דא"ר חנן כל הפסוק כולו לשיעורין נאמר), during a discussion of which berachah comes first if one has a choice among the "seven species", R' Hanan states the entire verse (with the seven species) was given in order to establish measurements, as opposed to the opinion that states the verse comes to tell us the priority order of blessings for the species.
- Yoma 80a (ושיערו חכמים אין בית הבליעה מחזיק יותר מביצת תרנגולת) states that a person's throat cannot hold more than one hen's-egg kabbeytsah.
- Keritot 14a (ושיערו חכמים דאין בית הבליעה מחזיק יותר משני זיתים) it states a person's throat cannot hold more than two olives. From here we must infer that a kazzayit cannot be more than half a kabbeytsah.
- Eruvin 80b (קא משמע לן דשתי סעודות הויין שמונה עשרה גרוגרות) states that the amount of food sufficient for two meals is eighteen grogerot.
- Pesahim 109a (חסדא רביעית של תורה אצבעים על אצבעים ברום אצבעים וחצי אצבע וחומש אצבע) states, "R' Hisda said, the Torah's reviit [measures] two fingers by two fingers by two fingers and half a finger and a fifth of a finger".
Maimonides' Halachot
Maimonides' (known as the Rambam) great halachic work the Mishneh Torah mentions various shiurim many times. To our great benefit, he gives a table of equivalents. He states (Laws of Bikkurim 6:13):
What is the full measure of a dough requiring (a blessing on, and separation of) Hallah? A full omer of flour - whether from one of the five grains or from a mixture of them - they all contribute to the measure. What is the measure of an omer? Two qabin, less one fifth. The qav is four login. The log is four revi`iot. And a reviit is two fingers by two fingers by two fingers and half a finger and a fifth of a finger. All the "fingers" are the width of the thumb of the hand.
Here you learn that the measure which contains a volume of ten fingers by ten fingers by three fingers and a ninth of a finger, approximately, is an omer. Likewise, a measure of seven fingers less two ninths finger, by seven fingers less two ninths finger, by seven fingers less two ninths finger is the measure of an omer, and these two measures are equivalent."
"And how much does this measure hold? About three and forty average eggs and a fifth of an egg. This is the weight of six and eighty sela`im and two thirds sela` of Egyptian wheat flour, which is the weight of five hundred zuz and twenty zuz of the Egyptian zuzim of the present time (e.g. When the Rambam lived in Egypt). A measure which contains about this weight of this kind of wheat flour, may be used for measuring for (the obligation of separation of) Halah in all locations."
Rambam rules that R' Hisda's view (mentioned above, from Pesahim) of the size of a reviit is halacha. It is also clear that the reviit is a measure of volume and not weight, since the weight equivalent is stated in terms of a specific kind of flour. He explains the relation between a grogeret (a dried fig) and an egg (Laws of Eiruvin 1:9):
"... its measure is two meals, which is about eighteen grogerot, which are about six medium eggs".
He further states (Laws of Shabbat 8:6):
"(for being liable for) heaping food, the measure is a grogeret. The 'egg' spoken of everywhere is a medium-sized chicken's egg. Anywhere it says 'enough to cook an egg', it means enough to cook a grogeret amount of the egg. The grogeret is one-third of an egg".
From these two halachot we learn that an egg is three grogerot. It should also be noted that "cook an egg" doesn't mean cooking a specific egg, but rather it means cooking a particular quantity of egg -- in other words, the mass corresponding to that measure.
At this point, Rambam has explained the exact size of a grogeret and a beitsah -- but he has not yet defined the most critical measurement, the kazzayit. In fact, nowhere in his book of halachah does he say exactly how much the kazzayit is, even though he says (Laws of Forbidden Foods 14:1):
"The general case of forbidden foods in the Torah, their measure is about an average olive..."
The Shulchan Aruch says that "some say" an olive is half an egg (או"ח 486:1 שיעור כזית יש אומרים דהוי כחצי ביצה) , but he brings no source there . His apparent source is Tosafot: "The measure of a kazzayit - some say it is half an egg".
The Mishnah Berurah and Pri Hadash say there: "The Rambam calculates a kazzayit as one third an egg". I do not know what source this comes from, and it appears to be incorrect. Rambam never equates the size of an olive to anything else, though he does say a grogeret is a third of an egg, as we have mentioned -- and he never says that a grogeret is the same as a kazzayit.
Using the equivalents given in the Laws of Bikkurim, we can give values to the common halachic measurements. We will use an average thumb of 2 cm based on the work of R' Na'eh (שיעורי-תורה,סימן ג סעיף כה, עמ' רמ"ט), and a 2.4 cm thumb based on the work of the Hazon Ish. Note that there is no listing for kazzayit, that is on purpose:
Measurements in cc's (fluid ounces): Measure "fingers" Na'eh Hazon Ish ---------- --------- ------------ --------- reviit 10.8 86.4 (2.9) 149 (5) log 43.2 345.6 597 qav 172.8 1.4 L 2.4 L omer 311.0 2.5 L 4.3 L beytsah 7.2 57.6 (1.9) 99.5 (3.4) grogeret 2.4 19.2 (0.65) 33.2 (1.1)
The Rambam gives further equivalents (Laws of Eiruvin 1:12 et. seq.) , but we will not bring them here. It is important to note that these measures are volumes and not weights, as many seem to think. Notice also that Rambam equates the measurements to the weight of a particular kind of flour, not an arbitrary weight. More proof of this concept can be found here (Laws of Hamets and Matsah 5:12):
"…and how much is the measure of halah? About forty-three and a fifth eggs - like the volume of a medium egg, not the weight."
Rambam clearly states the shiurim are by volume and not by weight. This also follows from R' Hisda's description of the reviit. Why is it, then that so many say that the measurements are in fact by weight? I believe it is for two reasons. First, shiurim are often given in ounces, without making it clear that the measurement should be in fluid ounces rather than weight ounces. Second, it is sometimes more convenient to give a measurement by weight, particularly when something is sold by weight rather than by volume.
Are chickens and olives smaller than in Talmudic times?
The Noda Biyehuda (R' Yehezkel Landau) in his commentary to the Talmud known as the Tzlach (on Pesahim 109a) compares two different methods mentioned in the Talmud for determining the beitsah. In Eruvin 80b the size of a meal is mentioned in terms of eggs. And in Pesahim 109a the reviit is given in terms of thumbs. The Noda Biyehuda writes that he carefully measured thumbs and eggs, and found they do not give the same measurements. In other words, the omer measured from thumbs did not equate to 43.2 eggs. Not only that, but he found that the measure using thumbs was twice as big as the measure using eggs. He assumed that human limbs had not changed size, and was therefore forced to assume that todays eggs are half as big as those of the days of Sages, since one must also assume that both statements of the Sages are equally true.
R' Na'eh in his book Shiurey Torah, brings many proofs from the Talmud that the Noda Biyehuda's position that eggs are smaller (or, indeed, that either people or animals have changed sizes) is not compatible with our Sages' statements. I won't bring all his proofs, as that would make this paper ten times longer -- rather, I will bring one of his more potent proofs.
He states (שיעורי-תורה,שער א, סעיף ב, עמ' א):
The Mishnah (Shabbat 76a) says, "One who takes out (of his domain) as much hay as fits in a ram's mouth (is liable)." And the Talmud there raises the objection that it was taught (that the quantity is) a grogeret! The Talmud answers, "They are the same measurement". This contests the baraitha that established the measure as a grogeret, since it seems we must say that it did not concern itself with the shrinking (of the size of) the grogeret. Because if the grogeret were to shrink, then indeed the measure (for which one would be liable) would shrink! ... and therefore if the grogeret shrank, so too would the ram's mouth shrink.
He brings many similar proofs from the Talmud itself. However, proving physical reality from within an halachic text is at best a weak proof. Therefore I wrote to many different experts in the fields of archaeobotany and archeozoology to get a definitive answer from the scientific community as to whether the chicken eggs and olives we use today are different in size from those of our Sages.
The consensus of opinion I got from the egg experts I contacted was that the eggs we eat today are probably bigger than those two-thousand years ago. Dr. Guy Barbato of Pennsylvania State University wrote me:
I can say with considerable certainty that egg size has increased since the domestication of the chicken. This has been due, mostly, for direct selection for egg mass.
In other words, we breed chickens selectively and pick the ones that lay bigger eggs, generally speaking. Over the centuries, the average egg size has increased rather than decreased. Other authorities say it has barely changed at all and the archaeological evidence appears to agree with them.
Regarding olives, I wrote to several experts. The most exhaustive and definitive answer was given me by Dr. Mordechai Kislev. He kindly sent me a reprint of an article he wrote (תחומין כרך י, תשמ"ט - "כזית -- פרי הזית כמידת נפח") years ago regarding precisely the topic I am investigating.
He mentions in the article that there are three major varieties of olive cultivated in Israel, whose sizes are different and can be categorized as "small", "medium" and "large" -- just as the Mishnah and Talmud describe the olives. Of further interest is that the Talmud says the mid-sized olive is called "agouri", meaning "one which holds onto" -- because it holds onto its oil. Of the three olive varieties grown in Israel, the middle variety is the one which gives the best oil yield! The article also mentions that all three varieties of currently cultivated olives have been found in archaeological digs in Israel from about the period of the Sages. We can be quite confident that today's Israeli olives are not substantially different from those of ancient times.
These three varieties are the "nabali", averaging about 5cc; the "suri" at 3cc and the "malisi" at 1.75cc. These are indeed the "olives" mentioned in the Talmud, and therefore the measures with which we should be concerned.
Practically speaking
From observation of real eggs, figs and olives one fact seems clear: eggs are bigger than figs, which are bigger than olives. In other words, kazzayit is the smallest measure and beitsah the biggest.
The two shitot (methodologies) I mention above, Na'eh and Hazon Ish, should also be discussed. I have measured my thumbs at 2.4 cm. I am an average-sized man, and I assume that my thumbs are close to "average". In fact, the original standard for the measure of an "inch" (2.5cm) was the width of a man's thumb.
R' Na'eh uses a 2cm thumb in his calculations, which is small for an adult man, but about average for an adult woman. Even if women are included in the "average thumb", 2cm is not reasonable -- the width should be more like 2.25cm. In any case, given that it is possible Hazal would have included women in the measurement (because some obligations, like kiddush and the four cups of Passover apply to them as well), we need to consider both measurements. When it comes to Torah obligations and prohibitions, we must be strict when there is a matter of doubt, or when presented with two otherwise reasonable alternatives. How so?
With respect to kiddush, the obligation is to say it over a cup which contains at least a reviit of wine ( (Laws of Shabbat 29:7) and Sh"A O"H 275). If the cup did not contain at least a reviit, one did not fulfill the mitsvah of kiddush. However, saying kiddush over wine is a Rabbinic mitsvah, so one may be lenient and use the smaller reviit.
Regarding the Passover seder, the obligation is to drink four cups of wine, each cup containing a reviit of mixed wine (Laws of Hamets and Matsah 7:11), which is up to three parts water and one part wine. One fulfills his obligation bedi`avad (post facto) if he drank the majority of such a cup; however, the actual obligation is to drink the entire cup. And at the time of the blessing, there must be at least a reviit of wine in the cup. Here as in kiddush, it is a Rabbinic mitsvah so we can use the smaller reviit.
Regarding matzah, the requirement is to eat no less than a kazzayit. I have seen opinions ranging from "an entire sheet of machine-made matzah" to "two-thirds of a sheet". So what is it, given what we have determined?
To answer this, I took three sheets of machine-made matzah, measured and weighed them. Each (17.5cm x 18cm x 3mm) matzah weighed 39g, and the powder resulting from grinding it in a mortar and pestle occupied 75cc. So the density of the matzah was 0.52, or about half that of water, which seems reasonable. Since the medium-sized kazzayit is 3cc, a kazzayit is only one-twenty-fifth of the sheet! Even allowing that the matsah is half as dense as water and so perhaps we should use twice as much -- that only amounts to one-twelfth of a sheet of matzah. This is considerably less than what most modern authorities say one should eat (based usually on the Noda Biyehuda and using weight rather than volume).
Let us assume for the sake of argument we are not certain that our kazzayit measurement is what the Sages meant. If we use a grogeret of matsah, we will definitely fulfill having eaten a kazzayit. Using the Hazon-Ish grogeret of 33cc, one fulfills the obligation of matzah by eating 0.44 matzah, or less than half! Of course, that is ten times more than the calculation based on actual olive sizes!
From the Talmudic sources and the scientific research, it seems that the "kazzayit" is an average Israeli olive. That would be the variety called "suri", whose average size is 3cc as mentioned before.
Though the Talmud states that the beitsah is a medium-sized chicken's egg, it seems the beitsah as we have calculated it, is larger -- whether by Na'eh (58cc) or Hazon-Ish (100cc) -- than the current average egg size, which is about 47cc.
I used to think this meant the "Talmudic egg" was just a standard measure divorced from actual chicken eggs, but what the Rambam says about "medium chicken eggs" made me rethink this issue. I looked on the USDA web site for information on eggs, and found that the medium grade, "Large", is 24 oz for 12 eggs, or 2 oz per egg (on average), which is about 57cc. The highest grade is "Jumbo", which is 30 oz for 12 eggs or 2.5 oz per egg (on average) or about 71cc. This translates to an approximate range of 57cc to 71cc. per standard North American chicken egg. Note that the standard eggs vary a great deal! In any case, this range certainly includes the Na'eh beitsah of 58cc, and is almost as big on the top end as the Hazon-Ish beitsah. The "average" size of 47cc includes smaller eggs -- the most commonly used egg, however, is the "large" or 57cc (avg.) egg.
It is interesting to note that the middle of the size category, "large" egg is almost exactly the size of R' Na'eh calculation. In order to accept the Hazon-Ish egg size of 100cc, we would have to use huge, mutant eggs which nobody has ever seen! By experiment one can verify Hazal's statement that a person's throat can hold no more than one beitsah. One "large" egg is as much as one can hold at one time. Regarding the statement in Keritot that the throat can hold no more than two kazzayit, we can resolve the contradiction either of two ways:
- A beitsah applies to food that is soft (like applesauce) and can fill all the volume of the throat -- but the kazzayit applies to hard food which can not be swallowed easily at once (like crackers).
- Or we might say the beitsah refers to the maximum possible amount one can swallow at once, whereas the kazzayit refers to the amount one can comfortably swallow.
Conclusion
The Sages gave us measurements in units which would be handy and familiar to all -- common foods which everyone knows. They did not expect we would walk around with apothecary scales or calipers, but that we would exercise common-sense and good judgement.
The size of a kazzayit is about 3cc, which is a little less than one teaspoon -- approximately the size of the first joint of your thumb. The evidence is overwhelming for this. The beitsah is the size of a USDA "large" egg. It has no particular relationship to the kazzayit, except that it is more than twice as big.
Based on my measured actual thumb-widths, the reviit should be 150cc rather than 86cc, but this forces the beitsah to be at the very top end of the egg-size scale rather than the "average". Since we know the beitsah corresponds well to a reviit measured by 2cm thumbs, we have to say that in fact a reviit is really just over 3oz (86cc). So how can we answer the Noda Biyehuda's argument? Our own measurements agree with his! One possible answer is that the "thumbs" are not thumbs on their own, but measured as they are commonly used to measure -- by pushing one up against the other (דחוק). In such a case, the width will be smaller and perhaps a 2cm average thumb is possible.
Nevertheless, until mashiaH comes and these matters are finally resolved, it is best to be cautious and use the large 5oz (150cc) reviit for Torah obligations, such as ensuring we are certainly required to make a final berachah; and use the small 3oz (86cc) reviit as a maximum to drink if we want to be certain we don't need to make a berachah or for kiddush for example.
I hope this exposition helps all of us understand halachic measurements more completely, and allows us to fulfill our Creator's commandments more fully.
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