Parshas Noach 5787
בכורות כב.
"מצא מין את מינו וניעור"
Our Gemara discusses one who purchases ציר (brine from a fish when it is salted) from an עם הארץ and must be concerned that it is טמא. Water was added to this ציר, which was then used as a dip and sometimes as an ingredient to flavor other cooked foods. One who wishes to be מטהר this ציר may perform השקה by touching it to the water of a mikvah. If the mixture consists mostly of water, השקה is effective because it is a valid method to be מטהר the water. If the fish brine is the majority and the water is a מיעוט, the mixture is not טמא anyway, since fish brine is merely the זיעה of the fish and is not considered an אוכל. The water is בטל to the fish brine and is not ר' ירמיה .טמא explains that this applies only when the ציר is used as a dip. If it is added to a pot containing other water, the water in the ציר, although previously בטל and considered טהור, combines with the other water and may become the majority over the fish brine, causing the mixture to be טמא. This principle is known as "מצא מין את מינו וניעור" - a מין can find its like מין and be reawakened, joining with the other like מין to become the רוב. A similar principle applies to פסול מים mixed with כשר מים. The (או"ח ס' ק"ס) שו"ע states that water used for tasks such as washing dishes is פסול for נטילת ידים. The (משב"ז ס"ק ה') פרי מגדים explains that if this מים פסולין falls into מים כשרים it does not need to be בטל בששים. As long as the מים כשר is the רוב even by a כל שהו, the פסול water is בטל and the mixture may be used for נט"י because something whose prohibition does not depend on טעם does not require ששים. The משנ"ב brings this להלכה and adds that this water may be used to complete the שיעור רביעית required for נט"י.
The (שו"ת או"ח ר"ז) מהר"ם שיק was asked whether one must be חושש that water dripping from his hands after the first נטילה which has become טמא through contact with his hands, will render the טהור מים in the cup טמא. Based on a ראב"ד the מהר"ם שיק answers that when נט"י is required because of טומאת ידים the water is not considered טומאה ממש. Otherwise, after the first pouring, the water on one’s hands would render the water used for the second נטילה tamei, making it impossible to purify one's hands. Rather, it is considered a לכלוך בעלמא and does not render the second water טמא. If it falls into the kosher מים it is בטל. The second נטילה is generally required to rinse away the water from the first נטילה which has become טמא through contact with one’s hands. However, the שו"ע states that if one pours a רביעית over his hands at one time, a second נטילה is unnecessary. The משנ"ב explains that a רביעית of water acts like a מקוה and is מטהר so the first water does not become טמא and does not need to be rinsed off. Since today’s washing cups generally hold more than a רביעית, the שאלה is not relevant in such cases. The מנהג of the חזון איש was to pour a רביעית or more on each hand without pouring a second time. Others maintain that even when more than a רביעית is
1) עיין קהילות יעקב ב"ק א' (2) חו"מ שעח:א( poured each time, one should still pour twice.