Shatnez - Yom Tov Purchases

QUESTION: Shatnez awareness when purchasing new clothing for Yom Tov:

May a linen shirt be worn under a wool jacket or wool sweater? Is this included in the issur of shatnez (prohibition of mixing linen and wool)?

ANSWER: Shulchan Aruch (YD 300:4) writes that it is permissible to wear a wool shirt on top of a linen shirt and even to tie them together, so long as they are not sewn together. However, Shulchan Aruch cites a stricter opinion that forbids tying the shirts together with a permanent knot. 

The Rema adds that it is proper to be strict not to wear wool on top of linen (or vice versa) if you cannot remove one without first removing the other. For example, one should not wear woolen socks on top of linen socks, since it is not possible to remove the linen without first removing the wool. The Talmud Yerushalmi explicitly prohibits this because on a Rabbinic level this is considered as though the two garments are attached. Although the Beis Yosef writes that we do not follow the ruling of the Yerushalmi, the Shelah (cited by Pischei Teshuva 300:6) writes that one should be strict about this, since there is no indication that the Bavli disagrees with the Yerushalmi.

Regarding our original question, it would depend on whether it is possible to remove the linen shirt without first removing the wool sweater or jacket. The Shach (300:10) explains that this is theoretically possible because one can first slip their hands out of the sleeves of their outer wool garment. They can then remove the linen under garment while still wearing their outer wool garment. This can be easily done with an outer loose or stretchable wool sweater. The same would also apply to wool tzitzis under a linen shirt. This is permitted, since the tzitzis can be easily removed while still wearing the linen shirt. However, if the shirt and sweater are tight and this cannot be done, although the simple reading of the Poskim in Shulchan Aruch (Shach, Taz, Levush) do not indicate that there is a problem, the Shevet HaLevi questions whether the above leniency applies (see Shevet Halevi 2:170 and 9:226). 

____________________________________________________

The Gerald & Karin Feldhamer OU Kosher Halacha Yomis is dedicated to the memory of Rav Yisroel Belsky, zt"l, who served as halachic consultant for OU Kosher for more than 28 years; many of the responses in Halacha Yomis are based on the rulings of Rabbi Belsky. Subscribe to the Halacha Yomis daily email here.