According to the Shaatnez testers of America

Suits and Sport jackets, (Men's/Boy's): Require testing even 100% polyester and 100% silk suits.

Why so? Isn't there a simple Sefek Sefeka? Safek if there is wool, and if there is wool Safek if there is Linen! This is even a Safek Sefeka HaMithapech. Why would they require testing?

(I'm not looking for an answer arguing against the entire practice of checking for Shaatnez)

  • Maybe it's considered "efshar levarer"? Apr 12, 2013 at 1:17
  • @ShmuelBrin even according to most the Poskim that hold you still need to check Be'efshar Levarer one doesn't need to check when it's not "Efshar Levarer BeKalut" and I don't think anything that takes a professional to check for would count as BeKalut. Apr 12, 2013 at 1:30
  • And if you'd like I can bring an exhaustive list of Rishonim and Aharonim that don't hold one must check BeEfsharim Levarer. Apr 12, 2013 at 1:33
  • Related: judaism.stackexchange.com/q/2597
    – msh210
    Apr 12, 2013 at 6:22
  • 1
    I doubt any polyester suit one could buy at a store has shatnez, but it could be away to support someone financially.
    – Ariel K
    Apr 12, 2013 at 13:49

1 Answer 1


The 100% in 100% polyester and 100% silk suits refers to the visible part of the suit.

Underneath that is an entire world of stuffing, reinforcement and other junk. The easiest place to see some of these is under the lapel; under the felt is something stiff, and it's not silk/polyester.

These hidden parts are made from whatever material the factory can buy at the cheapest price. It usually differs even from one identical suit to the next; depending on what came out of the sack next.

Shaatnez checkers will tell you that it's not at all unusual to find both wool and linen in these pieces, maybe even material made from both.

There's also the issue of the thread used for sewing on the buttons. Linen thread is still one of the strongest threads available.

BTW: Have you ever seen a zipper of 100% polyester or 100% silk?

To answer your question: There is only one Safek: Do the non-silk/polyester sections contain wool and linen?

Disclosure: My father was a Shaatnez checker for over 30 years.

  • why is the thread for sewing the button considered under the issur, I would think that maybe since it does not cloth you and therefor does not count. Apr 17, 2013 at 10:06
  • @YaakovPinsky - the Halacha is that a large piece of cloth that has a wool thread on one side and a linen thread on the other side is still Shaatnez, even if one wants to use the middle "clean" piece. Apr 17, 2013 at 10:16
  • How is that only one safek?
    – Double AA
    Apr 17, 2013 at 13:38
  • @Danny Schoemann - is that derabanan or deorita? Apr 17, 2013 at 14:58
  • 1
    @DannySchoemann No it's two safeiks: Did he hide linen? Did he hide wool? (We can go back and forth, but you're the one who thinks he has the right understanding. So why is it one safek not two?)
    – Double AA
    Apr 18, 2013 at 6:23

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .