Tuesday, September 17, 2013

Schach That is only Kosher on One Axis, and Eiruv Tavshilin a Few Days Before Yomtov.


The Chicago Rabbinical Counsel, pursuant to the psak of Rabbi Gedaliah Schwartz and Rabbi Shmuel Fuerst, has made it known that a certain commercially available fencing product is kosher to be used as Schach.  The original psak can be seen here.  However, they include a link to a caveat: it is only kosher when it is supported by some other schach other than this fencing- on bamboo, for example- and also that it lies perpendicular to the other schach.   The warning can be seen here.  If you remember your High School math, the Cartesian terms would be that this Schach is only kosher on the X axis.  If you place it on the Y axis, it will be passul.

Let's call it "X Axis Schach."

Here is a picture of the schach in use in a sukkah.

In the picture you can see a black line.  This is one of the wires that are woven through the reeds to hold them together.   A moment's thought should make it clear why this schach is only kosher perpendicular to the support bamboo.  If a moment's thought does not do it, I note the explanation below.

Unfortunately, from my examination of this product, I believe it to be mostly open, חמתו מרובה מצלתו.  It might be that since its use is limited to cases where it is perpendicular to other kosher schach, it can be assumed that between itself and the support schach there will be a total of צלתו מרובה מחמתו.  This, however, is a risky assumption, but well within the purview of reliance on one's poseik.  For skeptics, the only way to make a final determination would be to use a light meter and a flashlight in a darkened room. Rabbi Reuven Drucker, the Marah D'Asra of the Agudah of Highland Park New Jersey and Menahel of Yeshiva Rabbi Samson Raphael Hirsch in Washington Heights, is an expert in such determinations.

I was just informed that Rabbi Fishbane, head of the CRC, says that they did measure it and they found it to be tzilsa merubah.  Rabbi Fishbane is universally respected in the Kashrus World, has well established his credentials as a man to be relied upon, and I cede to his opinion.
Oddly, in the printed CRC information sheet, this schach is discussed, and the paragraph ends by saying that as in all cases, one should ensure that the schach is Tzilso Merubah.  Evidently, someone at the office was not convinced that it is mostly reed.

If the schach is placed parallel (Y Axis) to the support schach, then removing the wire would result in all the reeds falling down between the supports.  If it is placed perpendicularly (X Axis,) then even if the wire were to be removed, the reeds would stay in place.  Thus, when the fencing is parallel, the wire is the only reason the schach stays where it belongs, and under the rule of Maamid Bedavar Hamekabel Tumah the reeds are no more kasher than the wire itself.  It is like having a metal lattice holding up the schach.  (Many poskim are not concerned about maamid..)


On another topic:  Some people, not chalilah in reference to anyone who will be eating in my house this Yomtov, are obsessive about the Eiruv Tavshilin.  They are afraid someone (me) will forget to make the eiruv.    Others might themselves be worried that they will get busy and forget erev yomtov.  For those unfortunate compulsives, I have some advice.  Make the eiruv two or three days before yomtov.  As the Tur points out, his father, the Rosh, says that according to Rav Ashi, such an eiruv is kasher, and we pasken like Rav Ashi (as the basra.)  True, the Mechaber (OC 527, see, for example, here, in Seif 4 and 25 ) holds that lechatchila one should be choshesh for the shitta of Ravva (and the Maharshal that says that the Rosh's analysis is incorrect) and only rely on an erev yomtov Eiruv, but bedieved it is certainly kasher.  So for anyone taking this to heart, remember: if you make the eiruv a few days before Yomtov, or erev yomtov for the last days as well, it's kosher.  But don't make a bracha, neither now nor later on erev Yomtov.  And make sure the Eiruv food remains edible and available until Shabbos begins.


  1. Wow, Eruv Tavshilin before Sukkot: I lived in an alternative universe the last time I did that. Chag Sameach or Yom Tov Tov.

  2. I look forward to the day I can fondly reminisce about the 3 day Yomtov, too.

  3. Well we do get a taste of 3 day Yamim tovim when Rosh HaShana's 1st day falls out on Yom Chamishi. And we do Eruv Tavshilin for that. Since Rosh HaShana for all practical purposes has to be and will have to be a two day Yom Aruchta even in Eretz Yisrael, the three day Yom Tov will never completely disappear. But it is nice to start Simchas Beis HaShoeiva on Thursday night with instrumental music. It helps the Chag be more simchadick.

    Also I actually liked Shavuot with two days. One could listen to Sefer Ruth on the 2nd day without falling asleep. A 2nd day of Shavuot has its advantages. I don't miss the 2nd Seder on Pesach though. The kittel from the first night is already drenched with red wine.

  4. On a "three day Yom Tov," meaning when Yom Tov is on a Thursday and Friday, if you make the eruv on Wednesday, are you not already relying on the shittah of Rav Ashi by maing an Eruv on Wednesday for cooking on Friday? (Granted, the latter is Yom Tov Sheni, more room to be maikel I suppose. But then why not do it on Monday or Tuesday if you are nervous about forgetting.)

  5. Tal, good to hear from you. At first, I was flummoxed, but after some thought, I don't agree. If the svara is to be mevarer mana yafa, you have to do it erev YT, and it shouldn't make a difference if it's one or two yamim tovim. I think Rava would hold, even by a two day yt, that erev the first day would be appropriate. Do you have a makor to the contrary?

  6. Eliezer:

    Thanks. I will have to look into it on Yom Tov, bli neder. Acc. to the Aruch ha Shulchan you cite, it is based on a Rosh in Beitzah. What I am having trouble with is how a Wednesday Eruv works at all for Rava. (Especially if we are talking about Succos where we treat it as a true sefeikah de yoma, either one or the other is Yom Tov, not both, as opposed to Rosh ha Shanah.)

    I especially like the Aruch ha Shulchan's suggestion of making one eruv tavshillin for BOTH Sukkos and Shemini Atzeres!

    Have a very good Yom Tov.

  7. I owe you a follow up.

    1. The Rosh (Beitzah 2:1) is the one who suggests that one could make a single eruv for two Yomim Tovim when, as happened this year, there are two Thursday/Friday yomim tovim in a row.

    2. He states this AFTER he says that the nafka mina between Rava and Rav Ashi is making an eruv a few days before erev yom tov.

    3. The Beis Yosef is in doubt whether the Rosh's suggestion is only acc. to Rav Ashi (which would imply he paskens that way) or also acc. to Rava. Quite amazing that acc. to Rava, you cannot make an eruv two days before Yom Tov, but you can (acc. to one side of the BY's safeik) do so erev Sukkos for Shemini Atzeres.

    4. It seems, therefore, that Rava's understanding is that an eruv has to be on an erev Yom Tov. (Which is implied by the Mishna in Beitzah). Rava's reason is that one should make sure to set aside something for Shabbos, and that takes effect just before the festivities of Yom Tov begin. Odd thing is, perhaps one erev Yom Tov works for another.

    5. Acc. to that, it appears you are right -- when we make an eruv on a Wednesday for a Thursday/Friday two-day Yom Tov, acc. to Rava it works because it is erev yom tov -- in effect a mini version of what the Rosh suggests. So that is no proof that you can make one on Monday or Tuesday.

    6. Re your suggestion for someone who is worried he will forget to make one early, perhaps one could do so al tnai -- if you forget, then Monday's is the eruv, but if you remember, then Wednesday will be the eruv.

  8. Thank you for the methodical precis. I'll probably put it into the post before I move it to the finished product website. I do as you suggest- I make a tnai for the next yomtov with every ET.

  9. My impression was the standard psak is that we are only choshesh for ma'amid lechatchila, and would not invalidate it for that.

  10. Ohr Ganuz, a simple reading of the mechaber will show that there's nothing simple about it, since he assers a metal lattice below the schach. But I agree, most are mattir, as the Rama seemingly says befeirush. But the Chazon Ish and the Mishna Berura both encouraged being machmir (see MB סי' תרכט סקכ"ב, וסי' תרל סקנ"ט) I remember, as a child, that Reb Chaim Zimmerman, our upstairs neighbor, refused to use our sukkah until we divested it of maamidim mekablim tumah, at least directly holding up the schach.