Sunday, March 22, 2015

Kezayis Season

Pesach is rapidly approaching, which means that it's nearly time for people to obsess over the size of a kezayis. The monograph that I wrote on the evolution of the kezayis is by far the most popular piece that I have ever published - if you haven't seen it, you can download it at this link. Here are some follow-up posts on the topic:

Matzah/Maror Chart for Rationalists - so that you, too, can have a chart!

The Popularity of Olives - discussing why this paper is so popular and yet hated by some.

Why On Earth Would One Eat A Kezayis?  - discussing the strange notion that one should eat a kezayis of matzah on Seder night.

The Riddle of the Giant Kezayis Defense - wondering why many people would not accept that a kezayis is the size of an olive.

Maniacal Dishonesty About Olives - exposing an error-ridden critique that appeared in Dialogue.

It's Krazy Kezayis Time! - discussing the view that one should eat a huge amount of matzah in a very short time in order to fulfill all opinions.

Meanwhile, I am off to LA for three weeks. I probably won't have much time to post, but R. David Ohsie will be publishing a fantastic series of posts about Rabbeinu Avraham ben HaRambam's treatise on Chazal and science, and Rabbi Moshe Meiselman's claim that it must be a forgery. If you're in LA, please join me at the book launch for The Torah Encyclopedia of the Animal Kingdom, at Beth Jacob, Monday, March 30th, 8-10pm (and please spread the word!)

43 comments:

  1. Dear Rabbi Slifkin,

    In one of your linked pages, you write:

    [I have lots to say about the questionable notion of "following the views of as many Rishonim as possible," and how this relates to the difference between rationalist and mystical approaches to Judaism, but I'll leave that for another time.]

    Is there a link to where you discuss this? If not, I would be interested in what you have to say on it.

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    1. I think that I did post about it, but now I can't find it!

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  2. "So do you yourself really eat such a small portion of matzah and maror?" -- "Why on earth would I, or anyone, only eat an olive-sized portion of matzah and maror? "

    Obviously, you avoided answering the question. And it's not just about Pesach. On Shabbos meal (let's say on Seuda shilishi when you are not hungry) do you eat only [today's] olive size of bread within 4 minutes in order to say Birchas haMazon? In general, do you feel you fulfill Halachik obligations when you do what you yourself feel right or when you do what mainstream of poshkim consider right?

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    1. In general, I was taught that if I have studied a topic thoroughly, I am entitled to draw my own conclusions and follow them. However, I usually try to follow mainstream halachic opinion. However, I define "mainstream" in that regard as poskim who are of a ratinalist orientation and who are thoroughly conversant with the relevant sources and arguments.

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    2. When the renowned Rabbi Natan Slifkin misspells the most inconceivable word for him to misspell (r*********t), it is a true sign he has done to much Pesach cleaning.
      o

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    3. "In general, I was taught......"
      By whom?

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  3. Speaking of "rationailist arguments" I was troubled for years by the view that one should not drink water from the Kinneret during Pesach because someone may have thrown a crust of bread in it to attract fish or may have accidentally spilled a bottle of beer in it. The argument is that hametz is assur, even in the ratio of 1 to 1000, so that water is "contaminated". Full disclosure: I AM NOT A TALMID HACHAM but I always thought to myself that "this does not make sense". This can not have been what the Hachamim had in mind when they said "1 in a 1000 is still assur". Fortunately, last week a Rav gave a quick shiur after shacharit and he related to this question. He said that Rav Ovadiah Yosef said there is no problem because the Hachamim said "1 in 1000 is assur", but NOT "1 in a billion" which is permitted. He then said Rav Lior of Kiryat Arba/Hevron also said there is no problem because the "1 in a 1000" issur is referring to keilim (vessels like pots) but not to natural bodies of water. I was greatly relieved when I heard this, thinking to myself "kol hakavod to common sense!".

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    1. As it happens, Israel no longer gets most of its water from the Kinneret. Yerushalayim and its area have usually depended on wells, and desalination accounts for a huge amount. Tracking the level of the Kinneret is still handy for measuring rainfall and water availability, but it's not as central as it used to be.

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    2. > I was troubled for years by the view that one should not drink water from the Kinneret during Pesach because someone may have thrown a crust of bread in it to attract fish or may have accidentally spilled a bottle of beer in it.

      To what lengths does one have to go? Do you have to hold your breath if you pass a bakery on Pesach? There are particles of chametz in the air.

      > He said that Rav Ovadiah Yosef said there is no problem because the Hachamim said "1 in 1000 is assur", but NOT "1 in a billion" which is permitted.

      Was 1 in 1000 meant literally? It sounds like an idiom.

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    3. http://www.mcclatchydc.com/2014/03/20/221880/israel-no-longer-worried-about.html

      Read this article from a year ago, regarding Israel's water supply. They [we] have largely eliminated perennial concern over water shortages. It is exactly this type of know-how, and similar achievements in things military, technology, agriculture, etc. - that every day create a literal sanctification of God's name.

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    4. Make sure to wrap your matzah in plastic (they wrapped it in plastic in the midbar 40 years; you thought plastic was a modern invention? That's what happens when you go to college) and don't eat more than a minimum kzayit the whole eight days).

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  4. I feel posts such as this one is really anti charedi, anti bnei torah albeit dressed up in an olive.
    You see Rabbi Slifkin himself agrees that in Judaism there is room to be machmir. He himself is machmir. See his post 2 years ago when El Al made a mistake and sold their tickets at ridiculously low prices Rabbi Slifkin posted he would reimburse the airline what's due to them even though according to the strict letter of the law he may be exempt.
    I commend him for that. He was machmir in Halacha in a situation where he feels a Jew should be machmir.
    There are others who feel that by having one more bite of horseradish they are getting in the opinions of all Poskim. And feel they similarly are being machmir in a situation where a jew should be machmir.
    So why call them "obsessed"? Why all this hate? Perhaps you want to be slightly more broad minded and understand that different Jews apply their chumros to different areas od halacha.

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    1. Where do you see hatred? I don't hate people who do this! I just think its a pointless chumra hamaviyah lidei kulah (or even issur).

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    2. And there are those rationalists who point out that you can eat as much horseradish as you want and still not be yotze the mitzvah of marror. :-)

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    3. NachumMarch 23, 2015 at 4:10 PM
      And there are those rationalists who point out that you can eat as much horseradish as you want and still not be yotze the mitzvah of marror. :-)


      Actually that's taking the mystical approach :). The rationalist approach is more legalistic and thus precedent based. Or at least that is one way of looking at it.

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    4. You see Rabbi Slifkin himself agrees that in Judaism there is room to be machmir.

      The "right" reason to be Machmir is because one analyzes the halachah and considers the position to be sound. You are then actualizing your pursuit of the truth.

      The "wrong" reason is to be worried that you didn't maybe you didn't "get" the Mitzvah or that the act didn't feel sufficiently religious, so better safe than sorry or better to distinguish yourself from your lessers.

      At least that was the rationalist training that I was given.

      I assume that Rabbi Slifkin would not want to keep the money because he felt it would be wrong, even if halachically permitted, and at "worst" this would be going beyond the minimal requirements of the law. If he did it because that he didn't fulfill the Segulah for Parnassah, then you would have caught him in a contraction.

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    5. "Actually that's taking the mystical approach :). The rationalist approach is more legalistic and thus precedent based. Or at least that is one way of looking at it."

      I disagree. Rationalism is based on scientific and historical facts. The question is not intention or some other mystical idea, but whether or not horseradish is one of the plants listed as "marror" in the Mishna. It almost certainly isn't, for several reasons.

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    6. Eli,

      As one who has criticized Rabbi Slifkin before for anti-Chareidi posts, I believe I have the right to say that you are incorrect in this case. This is an example of scientific analysis of halachic sources, and this is where Rabbi Slifkin's expertise comes into play. That his conclusions are not necessarily palatable to the Chareidi mindset does not make the posts "anti"-Chareidi.

      Having said that, I am dismayed at the disrespect some commenters show toward Rishonim and their dismissal of the integrity of Mesorah (mostly from the comments on the posts linked to above). These comments display a complete lack of humility (see the transcription of Rav Soloveitchik's famous speech from the RCA convention).

      Finally, if I may, I don't believe that the opposite of "rational" ought to be "mystical." Has this been discussed before? Mystical is mushy. I'm searching for another term ("traditional" maybe?) that connotes a greater sense of intellectual heft to the opposing view. (Of course, many of the followers of this blog believe that anything other than the "rational" approach inherently has no intellectual heft!)

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    7. "Actually that's taking the mystical approach :). The rationalist approach is more legalistic and thus precedent based. Or at least that is one way of looking at it."

      I disagree. Rationalism is based on scientific and historical facts. The question is not intention or some other mystical idea, but whether or not horseradish is one of the plants listed as "marror" in the Mishna. It almost certainly isn't, for several reasons.


      If you take a purely scientific/historical approach, then you'll have to admit that in most cases of dispute, we have no way of knowing what the true history was. So, you would have to be Machmir in almost all cases of dispute (if possible). You would also have no way of discerning what to do in cases where both sides are both Machmir and Meikil. The idea of "majority" or "great man" deciding makes absolutely no sense scientifically, but it makes perfect sense in a legal system.

      You also can't explain the phenomenon of Sha'as Had'chack. If you are trying to recapture the historical moment, then why does the fact that something is difficult have anything to do with it.

      The correct approach is not scientific, but legal. Whether we have recaptured past practices is all but impossible to know; what we know is that we are attempting to follow the traditional method for answering questions. The practices for paskening make perfect sense in a legal system and none at all scientifically.

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    8. Oh, no argument there. I just believe that there are times when history is clear.

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    9. NachumMarch 25, 2015 at 8:35 AM
      Oh, no argument there. I just believe that there are times when history is clear.


      But once you admit that the deciding factor is not historical or scientific, but rather legal reasoning, then the fact the you can prove that at one time the halacha was X, doesn't mean that X is the halacha. Horseradish for Maror is a case in point.

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  5. Regarding what MK said above about the view that somehow, it is more spiritually fulfilling to carry out the
    the maximum number of de'ot of the rishonim as possible....I have never really understood this. As I said in my previous comment, I am not a talmid hacham, so I really don't understand how the poskim came to the decisions they did. However, a reading of the TANACH does't indicate anything like this...it simply enjoins us to carry out G-d's law. My understanding is that HAZAL, in their discussions in the Talmud were trying to recreate an understanding of that law to the best of their ability because it had been lost or blurred due to exile and persecution. I recall seeing a comment in the Talmud that said (please correct me if I am wrong!) that when the split between Beit Hillel and Beit Shammai occurred, that was a day of great sadness for Am Israel. Now, we follow Beit Hillel who us usually more lenient. In fact, it is forbidden to do like Beit Shammai in things like Keriyat Sh'ma. So why is it more "spiritual" to be machmir most of the time? I agree that it seems wise to generally follow mainline p'sak, so, for instance as an Ashkenazi, I do not eat kitniyot on Pesach, but I do respect the modern view of those hold that now since we are in a time of Kibbutz Galuyot (ingathering of the exiles) this humrah ought to be abolished.
    This is why I find Rav Slifkin's writings so refreshing....he is willing to ask questions like this and to ask if being machmir on everything really means that the person doing this has more "yiryat shamayim" as a result of this.

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  6. Is any of this relevant to the size of a revi'is. I read it should be equal to 1.5 eggs. Is this an original amount or a 'worked out' amount? how much would you say a revi'is is today and why? thanks

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    1. A revi'is is 75cc, not 86cc, as R. Chaim Naeh mistakenly concluded. See here:
      http://www.yeshiva.co/ask/?id=4348

      75cc is also the shiur that was traditionally used in Europe.

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  7. Eli, it's not a matter of hatred, but of realism. While humrot based on legal views can be justified, flying in the face of reality is not. Simply measure the volume of the largest olive to be found in markets and compare that to the volume of a large egg. You will find that it is much less than 1/3, not to mention 1/2. Legal views can't change reality - at least not with any pretense to rationality. The same is true for the volume of eggs in a revi'it (1.5 eggs) compared to the 10.8 cubic etzba'ot that is directly derivable from the sugya in the Talmud. You will find that a reasonable measure for the ama and etzba is perfectly consistent with the volume of a large egg. There is no need in reality to double the volume of modern eggs to achieve a revi'it. While the shita of the Nodah Biyehuda (Tzelach) upon which the doubling is based may have been true for the eggs of his time, it is no longer true.

    Your comment about eating more horseradish to fulfill the maror requirement according to all opinions is instructive. There is no indication that the acceptable maror species mentioned in the Talmud includes horseradish - a European plant. Moreover, it has a sharp rather than a bitter taste. It was used for maror in Eastern Europe because that was the only such vegetable available in Pesach. To fulfill the mitzvah of maror, one should use a type of lettuce - as per the Talmud. While it is customary in many homes to use a combination of lettuce and horseradish, to maximize the latter and minimize or eliminate the former is to be machmir on a minhag and makil (or disregard) on the din - as R' Natan noted.

    Y. Aharon

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    1. There is no indication that the acceptable maror species mentioned in the Talmud includes horseradish - a European plant. Moreover, it has a sharp rather than a bitter taste. It was used for maror in Eastern Europe because that was the only such vegetable available in Pesach. To fulfill the mitzvah of maror, one should use a type of lettuce - as per the Talmud.

      While I do use lettuce instead of horseradish, continued use of horseradish is easily justified although it doesn't correspond to what was originally intended. Once horseradish became accepted as Maror because of the scarcity of lettuce, it make perfect sense to continue to sanction its use, if you interpret halacha as a legal system.

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    2. If maror is not available in your country, bad luck you can't perform that mitzvah. The truism that halacha is a legal system does not give you license to substitute another vegetable that is a) not bitter and b) a root.

      I don't know why some people get such a kick out of making pomo justifications for haredi obscurantist imbecility.

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    3. Gavriel mMarch 26, 2015 at 4:31 PM
      If maror is not available in your country, bad luck you can't perform that mitzvah.


      That is your view, but apparently it is was not accepted.

      The truism that halacha is a legal system does not give you license to substitute another vegetable that is a) not bitter and b) a root.

      No one made that argument. The argument was that it is insufficient to show that "practice X" doesn't correspond to the practice at "time Y" to show that it is non-halachic.

      I don't know why some people get such a kick out of making pomo justifications for haredi obscurantist imbecility.

      Not to personalize this, but my grandfather was nowhere near being a Charedi and he used horseradish (or so I seem to remember). I think that this is quite a widespread custom outside the Charedi community.

      So there is no nail here for the application of the lone hammer in your toolbox, IMHO.

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  8. david, the figure of 6 eggs per lug, or 1.5 eggs per revi'it halug is an explicit Talmudic value. The volume of a revi'it is also given in terms of cubic etzba'ot (thumb widths). The latter is derived from the equation of 1x1x3 amot (of a minimum mikva) has the volume of 40 seah or 40x24 lug. Converting to etzbaot and revi't we have: 3x24x24x24 cubic etzbaot (ce)= 40x24x4 revi'it (r). Then 10 r = 108 ce and 1r = 10.8 ce. If we take an ama as 50 cm (19.7 inches), the an etzba is (2.083 cm) and a ce is 9.042 cubic cm (cc). 10.8 ce is then 97.66 cc. There are 29.57 cc in a fluid oz., then 1 revi'it is 3.30 fl. oz. That was the volume of 1.5 eggs measured by Harav Moshe Feinstein. Others may differ, but you're on safe grounds relying on Rav Moshe's ruling - especially when it is based on actual measurement and is perfectly consistent with Talmudic values as outlined above.

    Y. Aharon

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  9. R. Slifkin -

    Have you (or anyone else) ever looked into the eggs that the Noda BeYuhda would have had access to in Prague of the 18C? Maybe they were smaller than those commonly available to us...

    This would throw off all the calculations based on his chumra.

    J .S.

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    1. That, as well as the suggestion that maybe their thumbs were larger than ours, or smaller than ours, or the olives were bigger, or the olives were smaller, or the measuring units changed, etc etc etc etc - have all been examined thoroughly, many times over, by many different people. There's no substance to any of it. It's all just typical chumrah-creep, stemming from the usual general reasons (modern affluence, the desire to make an impact in halacha, the desire to be creative, the lack of "mimetic" tradition, the influence of ballei teshuvah, the ease of printing books, the lack of central authority, etc) as well as the specific Pesach notion of competing for the biggest chumrah.

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    2. Your list of the "usual general reasons" is a useful one ... "the desire to make an impact in halacha" seems to be one that doesn't get the attention that it probably needs.

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    3. I can't find the source right now, but I wrote notes on the subject years ago. I wrote down that the Noda B'Yehuda's egg was 46 or 47 cc. He notes in his discussion, the size of the egg in his contemporary measurements.

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  10. Is the proper volume that of an olive as it once typically was (assuming we know that) or the volume as it now typically is?

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    1. We know that olives have always been about the same size, so it's not a question.

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  11. J., while my value for the ama, 50 cm (19.7 inches) that was used in my calculation of a revi'it may be a bit high, it has the advantage of reconciling the actual size of current eggs with the Talmudic calculation of the shiur of a minimum volume mikva in terms of cubic etzba'ot and revi'ot. The resulting revi'it volume of 97.7 cubic cm is consistent with the actual volume of modern large eggs. The smaller shiurim of 75 and 86 cubic cm that you referenced correspond to an ama of 18 and 19 inches, respectively. With reference to your citation, I am reluctant to rely on volume measurements that are based on weights since the bulk density of the item is what allows the conversion, and the bulk density of particles will vary with conditions. The use of the weight of a d'hram coin is based, I believe, on the Rambam's measurement for the shiur of challah. He converted that volume in egg units to the corresponding weight of flour. The bulk density of the flour is then as issue as well as the actual weight of the coin that the Rambam used. That density depends of the fineness of the grind and the extent of tamping - if any.

    J.S. I don't have information on the egg volumes in Rav Landau's (Nodah Biyehuda) 18th century Prague, but Rav Yechiel Michel Epstein (Aruch Hashulchan) living at the turn of the 20th century in Lita noted that the eggs of his day became essentially doubled in volume after the import of a hen breed that produced the large eggs. The volume is what we presumably have today.

    Y. Aharon

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    1. Y. Aharon - The Rambam in Peirush Hamishnayos (Eiduyos 1:2) equates a revi'is to 27 Dirham, so there's no need to extrapolate from flour. The Dirhams we have from then all weigh between 2.7-3 grams, which is strongly supportive of the smaller shiur.

      There's numerous other lines of evidence for a 75cc revi'is, all brought in R. Hadar Margolin's "Kuntres Shiur Harevi'is", which can be found at this link:

      http://www.dafyomi.co.il/lectures/reviis/kuntras-reviis.pdf

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  12. J. I don't have the Rambam's commentary on Eiduyot available at the moment. However, a volume measurement can't be converted to a weight without a value for the density. The density of what? If the subject of the Rambam in Eiduyot is water, then the density is 1.00 g/cc, or a volume of 73 - 81 cc according to the range of the coin weights that you gave. That would be consistent with the 75 cc volume of a revi'it that you seem to prefer. I have no problem with that if it is consistent with the volume of the labeled medium sized egg in the marketplace (Rav Moshe apparently used large size eggs for his measurement since that was the medium sized category sold - small, medium, large, extra large, and jumbo).

    In any case (as a point of information), the Rambam in his Mishne Torah hilchot Bikurim 6:13-15 states the minimum volume of bread dough that requires removing the kohanic portion (challah) is that made from 1 omer of flour or 1.8 kav. That comes to 7.2 lug, or 28.8 revi'it, or 43.2 medium egg volumes. He also gives an equivalent weight of flour in terms of what was available to him (Egyptian flour weighing 520 Egyptian zuz). You would need to know the weight of an Egyptian zuz of the Rambam's time (13th century) and make some assumption about the fineness of the flour and whether it was aerated, i.e., falling from a sifter, or compacted in order to convert the stated weight to a volume of the flour. If you had that information you could deduce the Rambam's value of the ama and etzba since the above shiur for challah is taken by him as 311 cubic etzba'ot.

    Y. Aharon

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  13. More on egg sizes and volumes (pertinent to the shiur of a revi'it). Consumer hen eggs in the US are graded by weight with the most common sizes being medium, large, and extra large (17, 51, and 24% of an average hen's production, respectively). Their weights are 49-55 g, 56-62 g, and 63-69 g, respectively. Taking average masses for each size category, we have 52, 59, and 66 g, respectively. Taking the egg density as 1.033 g/cc (as reported in a Google search), we have the corresponding volumes of 49, 57, and 64 cc. The revi'it is 1.5 egg volumes which comes to 74, 86, and 96 cc. respectively. Thus the 75 cc value that J prefers is that corresponding to an average medium size egg, while Rav Chaim Noeh's value of 86 is that of an average large egg (it is not erroneous). The average large size egg is also close to an overall average size consumer egg based on the production percent that I cited (the value that I calculated (3.30 fl. oz), based on a 50 cm ama, is slightly larger than the value based on an average extra large egg).

    Y. Aharon

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  14. There is also a question of precision. Chaza"l use kezayit as a standard unit of dry volume because it was easy to estimate. That is true if you are looking for 10-20% accuracy. It isn't if you assume you have some volume measured to the precision of a modern physics lab. Consider that the standard is a "medium-sized" olive. How accurate can that "medium" be estimated. Depending on what kind of average is being implied a 1% accuracy would imply a sample size in the thousands. In a modern grading system "Medium" olives run 105-120 olives per pound, about a 12.5% range.

    The difference between an 86cc and a 75cc reviis implies about a 4% difference in the length of an etzba. Is there any reason to suppose measurements in the time of Chaza"l were that accurate or consistent?

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    1. Mike S., I agree with your assumption and would state the case more strongly. The sages presumably intended their shiurim to be used by the average person. It is unreasonable to expect that person to accurately assess an 'average' olive or egg. He can only estimate the associated volumes based on his experience with those typical commodities. Estimating the volume of a revi'it based on 1.5 'average' volume eggs is easier than estimating the minimum shiur of matzah based on the olive. You would need to break down a matzah to olive sized pieces and build up the layers to give perhaps double the estimate of an 'average' olive (to allow for the spaces between the matzah pieces). Once you do that, you should be done. The measurements based on number of matzot per pound and the density of matzah meal are also inexact and overly stringent since there is no apparent need to break down the matzah that finely to get the weight corresponding to a given volume - just as there is no need to squeeze a piece of sponge cake to get the shiur that requires eating in a Succah (sorry about the mixed Yomtov metaphor). Moreover using a Zayit volume equivalent to 1/2 or 1/3 egg is overly conservative and unrealistic - as R' Natan has elaborated, not to mention the totally unrealistic consideration of doubling todays egg volumes. There should be no need then to force down a whole matzah (or 2) as a supposed minimum shiur (or even 1/2 a matzah). Don't rely on some anonymous blogger (i.e., me), however, but on a Posek who gives reasonable and realistic shiurim. I recall that Rav Williger of YU has a long essay on the subject.

      Y. Aharon

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  15. Sorry, I should have checked prior to my last post. The name of the Posek, a rosh yeshiva at YU and Rav of the Young Israel of Riverdale, is Rav Mordechai Willig (not Williger).

    Y. Aharon

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  16. Interesting comment on "Parsha Blog" "the gemara states that a cohen's kemitza for mincha must contain at least 2 kezaisim should make it clear that the bloated shiurim are totally off."

    Avi

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