19. 70% polyester, 30% wool. If a piece of fabric is made of threads which are in turn made mostly of one type of fiber and partially of another type, e.g., 70% camel wool [whose name is similar to sheep wool (תוי"ט פ"ט כלאים מ"א )] or polyester or the like [even if its name is not similar to sheep wool (תשב"ץ ח"ב סי' ד', הג' רע"א יו"ד סי' רצ"ט )] and 30% sheep wool, the fabric is not considered to be made from sheep wool since the sheep wool is botul berov and one may sew the fabric with linen (שו"ע סי' רצ"ט ס"א ).
20. Wool is distinguishable. Some say this is only true if the wool fibers are not distinguishable in the fabric, but if they are distinguishable [even only to an expert, but as they are, without unraveling or singeing the thread (מו"ר מלבושי ישע פ"ב הע' ל"א )], they are not botul berov, even though they are the minority (שו"ת תשב"ץ ח"ב סי' ד', שו"ת שבט הלוי ח"ז סי' קע"ג ). This is because in any mixture of issur and heter, if the issur is distinguishable, it is not botul even if it is the minority (כעין מה שמבואר ברמ"א יו"ד סי' צ"ח ס"ד ).
21. Others say even if the sheep wool is distinguishable it is botul. They hold this is not the normal application of bitul berov found throughout halochoh since wool and linen alone are each muttar. Rather, the reason for this heter is that the issur of shaatnez only starts after the threads are spun. If there are different types of fibers in a thread, the thread is viewed as if it was spun from the majority material, not the minority. Hence, even if the minority of wool fibers are distinguishable, one may sew those threads with linen thread (שו"ת נודב"י מהדו"ת סי' קפ"ו, ערוה"ש יו"ד סי' רצ"ט ס"ד, ח זו"א יו"ד סי' קפ"א סק"ט, שו"ת מנח"י ח"ו סי' קט"ו ).
22. 60% polyester, 30% wool, 10% linen. If a thread is mostly made up of a different material and partially made up of even wool and linen, we follow the majority and the entire thread is considered to be made from the other material and is not shaatnez. Even if the other material only nullifies either the wool or linen, but not the two together, e.g., 45% polyester, 25% wool, and 30% linen, the entire thread is considered to be made from the other material; it is not shaatnez (שו"ע סי' רצ"ט ס"א ) and may be sewn with either wool or linen.
23. It should be pointed out that these halochos are just some general rules about threads or fabrics composed of different materials. One should not derive from here that any garment that has a minority of wool or linen does not need to be checked. Even if the fabric itself is not shaatnez, several garments have additional threads, fabrics, lining, or pieces of cloth which are shaatnez. Besiyato dishmayo, in the next issue we will give several examples.
