In Parshas Acharei Mos the Torah commands us in the mitzvah of ki’sui hadam – covering the blood after a bird or a chaya (wild animal) is shechted. The mitzvah does not apply to beheimos (farm animals).
There is a machlokes as to the appropriate time to make the berachah on the mitzvah of ki’sui hadam. The Rosh, in the sixth perek of Chullin (Perek Kisui Hadam), quotes the Behag that says the proper time to recite the berachah on this mitzvah is after the blood is already covered. Although generally a berachah is recited prior to the performance of a mitzvah (over la’asiyason), regarding the mitzvah of ki’sui hadam we are unable to recite the berachah prior to its performance. The Rosh explains that this is because this mitzvah is actually a part of the mitzvah of shechitah; it is the conclusion of the mitzvah. Therefore, after the shechitah (prior to the covering of the blood), one is in the middle of a mitzvah, and one should not recite a berachah in the middle of a mitzvah.
The Rosh agrees with the Behag that one should not make a berachah in the middle of a mitzvah. However, he argues with the Behag regarding the nature of the relationship that the mitzvos of shechitah and kisui hadam share. The Rosh says that the mitzvah of kisui hadam is a separate mitzvah, and not a conclusion to the mitzvah of shechitah. Therefore, one should recite the berachah of kisui hadam prior to covering the blood, in accordance with the general rule of over la’asiyason.
The Bais Halevi, whose yahrzeit is this month, (teshuvos, chelek 2 siman 14) points out an apparent contradiction in the opinion of the Rosh. Regarding the proper time to recite the berachah on washing one’s hands, there is a machlokes as to whether the berachah should be recited prior to drying one’s hands or after they are already dried. The Or Zaruah (siman 79) and the Hagaos Ashrei (Berachos 2:11) are of the opinion that one should only recite the berachah after they have dried their hands. The Rosh, in Pesachim 1:10 and in Berachos 3:34, says that one should recite the berachah prior to drying one’s hands. The opinion of the Rosh regarding ki’sui hadam was not to make a berachah in the middle of a mitzvah. He only argued that one should make the berachah on kisui hadam between the shechitah and the covering because it was a separate mitzvah, not in the middle of the mitzvah. Since the drying of one’s hands is surely not a separate mitzvah from the mitzvah of washing one’s hands, the time in-between washing and drying should be considered “in the middle of a mitzvah.” To be consistent with his ki’sui hadam opinion, the Rosh should have stated that one not recite the berachah until after he dried his hands, when the mitzvah is complete.
The Bais Halevi answers that we must properly define what is considered to be “in the middle of a mitzvah.” In order to be considered the middle of a mitzvah, a functioning initial part of the mitzvah must have been completed. In the example of the mitzvah of shechitah and kisui hadam, the shechitah is functioning and complete after the shechitah regardless of whether the kisui hadam is ever completed. The shechitah is affective, and one may eat the meat even if the blood is never covered. Thus, if kisui hadam and shechitah were viewed as one mitzvah, we would consider the time after the shechitah to be in the middle of a mitzvah.
Whereas regarding the mitzvah of washing one’s hands, the time after the washing (until they are dried) is not considered to be in the middle of the mitzvah, because, without drying one’s hands the washing is not affective. One may not eat until he has dried his hands. Therefore, the time after one washes his hands before they are dried is not considered to be in the middle of the mitzvah, since a functioning part of the mitzvah has not yet been completed. Although a certain aspect of the mitzvah has technically begun, we consider this point to still be the beginning of the mitzvah. As a result, the Rosh is consistent in saying that one should make a berachah prior to drying his hands.