One of the last items my father, Rabbi Berel Levy, ob”m, gave a hechsher to was bamboo schach. Why is a hechsher needed on schach?
In order for schach to be considered kosher, it must follow certain guidelines. The schach must be made from something that grows; it must be cut off from the ground and must not be considered a vessel of receiving. It must also be used to provide shade.
The schach certified by the OK is made from bamboo mats. In the Mishna and, subsequently, in the Shulchan Aruch, it states that if the mats are made to sit on (as in countries where they sit on the floor, or in countries where they sleep on mats) they would not be considered kosher for schach. In addition, if the material is used for roofing year round, it is questionable whether it would be kosher for schach.
The mats we certify are made in China. Today, in China, mats are usually made for shades and not for sitting on. They are also used as small placemats for eating, but they are not suitable at all for schach as they are not the appropriate size. The Talmud tells us that shades are considered a vessel that is mekabel tumah (subject to ritual impurity), because sometimes people wrap themselves in shades to protect themselves from the sun. Obviously this a shade made from material that can wrap around a person; a hard wooden shade would not necessarily fit into this category.
Even though it is possible that these mats would be kosher even if they were made for shades, we have instituted some changes to ensure the highest level of kashrus. First, we require the company to make mats with thicker pieces of bamboo wood every foot or so, which makes sitting on them uncomfortable and also impractical to use as a window shade.
In addition, while visiting the factory, I had the owner write up a sign, in Chinese, (to be hung up in the factory) stating that the mats being produced now are made for shade and religious purposes. To ensure that the sign stated exactly what I requested, I took a copy of the sign and showed it to various Chinese-speaking people, from hotel personnel to airline passengers on the plane ride back from the facility, and asked them to please translate the sign. It was indeed written as I requested.
In Kenya, these mats are made for use as roofing year round, which would be a problem to use as schach.
The bamboo mats are usually woven or held together by string. The string could also present a kashrus problem. The string used to tie the bamboo mat should also be made from something that is kosher for schach, so we require 100% cotton string. This is because the Shulchan Aruch tells us that a davar hamamid (literally “thing that makes stands,” i.e. a key element) that is mekabel tumah is not kosher.
What does this mean? When laying the schach on the sukkah, you usually lay it on sticks. It is not preferable to lay the schach on metal bars, however, b’di’eved (after the fact) it is acceptable. This means that the supports for the schach should only be made from something that is kosher for schach l’hatchila (in the first place). Similarly, if you were to use something non-kosher to hold together the schach, it would also present a problem. Synthetic string is not kosher for schach, hence cotton, which grows from the ground, is preferable.
How do we make sure the company is using cotton string when synthetic string is cheaper and stronger? During production, we send a mashgiach to the factory to make sure that the sign stating the mats are produced for religious purposes is displayed and to check that the string is 100% cotton. The mashgiach checks the string by burning it. If it is synthetic, the string melts and drips, but if it is cotton, then it will burn and have a pungent odor like burning hair. In addition, when the mats arrive in the United States, we take samples of the string to laboratories, like the Shatnez Laboratory, to make sure that it is 100% cotton. One year we found that the company had sent part of the shipment of mats made with string that was not 100% cotton, so we could not, and did not, certify that lot. In addtion, the OK is the only kosher supervision agency that sends a mashgiach to oversee production every time schach is produced.
Some people question the validity of using string, because there is an opinion that rope is not acceptable for schach, because it may be mekabel tumah. In the Shulchan Aruch HaRav, it is written that a rope is not mekabel tumah. Others, however, are of the opinion that rope can be mekabel tumah, because poor girls can use it as jewelry (i.e. if the rope is braided). Even among those poskim that hold that rope is mekabel tumah, they do not hold that string is in the same category as rope. Therefore, this is not pertinent to our situation because the shach is tied with a thin string and is not held together by rope. 1
If for some reason one is still not comfortable with using string, Rabbi Moshe Shaul Klein, shlit”a, from the Bais Din of Rav Wosner, shlit”a, suggests putting X-shaped support sticks underneath the mats to ensure that there is absolutely no question since the mats would be functional even if they were not held together by string.
The bamboo mats certified by the OK have enabled thousands of Jews to have easy-to-use, kosher schach for their sukkahs. Rabbonim and Jews all over the world use the bamboo mats to cover their sukkahs, in remembrance of the way that Hashem covered the Jews with the Clouds of Glory as they wandered through the desert.
1 See Kovetz Ohr Yisroel, Volume 49, pages 63-67, where this is discussed at length.