This week’s learning is sponsored by Helen Danczak. “My dear Uncle Phil passed on August 27 with family at hand. He was the kind of Uncle that the kids (of all ages) gravitated to. I am not alone in saying he was my favorite uncle. He is missed. May his neshama have an aliyah.”
Masechet Avodah Zarah
Masechet Avodah Zarah is sponsored by the Talmud class of Congregation Beth Jacob in Redwood City, CA, in honor of the Hadran staff who make learning possible.
Want to dedicate learning? Get started here:

Avodah Zarah 68
Summary
Today’s daf is sponsored by Terri Krivosha in memory of her mother, חני מנדל בת שימה פיגה וירחמיאל הכהן, on her second yahrzeit. She was an eshet chayil whom we miss and think of every day.
Rabbi Shimon and Rabbi Meir dispute whether a mixture is prohibited when the forbidden component imparts a bad taste to the permitted food. Ulla and Rabbi Yochanan differ on the scope of the dispute between Rabbi Shimon and Rabbi Meir: Ulla holds that they disagree when the forbidden item initially gives a good taste and only later turns bad, while Rabbi Yochanan holds that they disagree in a case where the bad taste is immediate. A challenge to Ulla’s view is raised and resolved. The Gemara then asks whether Rabbi Yochanan holds that they disagree in both scenarios, but the question remains unresolved.
Rav Amram raises a difficulty with Rabbi Yochanan’s view, noting that this debate is absent from the Mishna. After further searching, he identifies what seems to be the same dispute in Mishna Orlah 2:9. Rabbi Zeira, however, rejects the connection, explaining that the prohibition there rests on a different principle. A braita is then brought that directly supports Rabbi Yochanan: it describes a dispute between Rabbi Shimon and the rabbis regarding two leavening agents — one of truma, one of chullin — each potent enough to leaven dough on its own. Since adding both would cause over-leavening and produce a bad taste, this proves that there is indeed a debate in cases where a prohibited item imparts a bad taste. The braita lists another disputed scenario — when both leavening agents are added simultaneously. Abaye explains the need for this case: it was brought to clarify Rabbi Shimon’s position that even when the prohibited agent initially aids leavening, if it acts in tandem with the permitted agent, it is not considered to have been beneficial to the dough initially, and therefore, the dough is permitted.
A case is brought where a mouse fell into a barrel of beer, and Rav prohibited the consumption of the beer. Some assumed Rav ruled like Rabbi Meir, prohibiting mixtures even when the forbidden element imparts bad taste. Rav Sheshet instead interprets Rav’s decision as a special stringency regarding sheratzim (creeping creatures), and two objections to this reading are resolved. Rava rejects Rav Sheshet’s explanation and holds that if a prohibited item imparts bad taste, the mixture is permitted, and suggests either that the halakha is not in accordance with Rav, or that Rav held the mouse imparted a good taste to the beer.
This week’s learning is sponsored by Helen Danczak. “My dear Uncle Phil passed on August 27 with family at hand. He was the kind of Uncle that the kids (of all ages) gravitated to. I am not alone in saying he was my favorite uncle. He is missed. May his neshama have an aliyah.”
Masechet Avodah Zarah
Masechet Avodah Zarah is sponsored by the Talmud class of Congregation Beth Jacob in Redwood City, CA, in honor of the Hadran staff who make learning possible.
Delve Deeper
Broaden your understanding of the topics on this daf with classes and podcasts from top women Talmud scholars.
New to Talmud?
Check out our resources designed to help you navigate a page of Talmud – and study at the pace, level and style that fits you.
The Hadran Women’s Tapestry
Meet the diverse women learning Gemara at Hadran and hear their stories.
Avodah Zarah 68
שֶׁאֵין רְאוּיָה לְגֵר — אֵינָהּ קְרוּיָה נְבֵלָה.
and any carcass that is unfit even for a ger toshav to consume, e.g., one that turned rancid and is unfit for consumption, is not called an unslaughtered carcass with regard to its prohibition.
וְרַבִּי מֵאִיר, הָהוּא לְמַעוֹטֵי סְרוּחָה מֵעִיקָּרָא, וְרַבִּי שִׁמְעוֹן — סְרוּחָה מֵעִיקָּרָא לָא צְרִיכָא מִיעוּטָא, עַפְרָא בְּעָלְמָא הוּא.
And what can Rabbi Meir respond to this? He could say: That verse is written to exclude meat that was rancid at the outset, i.e., that was not fit for consumption even before the animal’s death, due to a defect in the animal. By contrast, a carcass that was fit for consumption when the animal died and was consequently rendered forbidden remains forbidden even when it becomes rancid. And Rabbi Shimon could counter that meat that was rancid at the outset does not need specific exclusion by the verse, as it is considered as mere dust and does not fall under the category of an unslaughtered animal carcass.
אָמַר עוּלָּא: מַחְלוֹקֶת שֶׁהִשְׁבִּיחַ וּלְבַסּוֹף פָּגַם, אֲבָל פָּגַם מֵעִיקָּרָא — דִּבְרֵי הַכֹּל מוּתָּר.
§ Ulla says: This dispute between Rabbi Meir and Rabbi Shimon is with regard to a forbidden food that enhanced the flavor of a dish when it first fell into it and subsequently detracted from its flavor. In this case Rabbi Meir deems the dish forbidden, since the forbidden food enhanced its flavor at the outset. But in a case of forbidden food that detracted from the flavor of the dish at the outset, everyone agrees that it is permitted.
אֵיתִיבֵיהּ רַב חַגָּא לְעוּלָּא: יַיִן שֶׁנָּפַל לְתוֹךְ עֲדָשִׁים, וְחוֹמֶץ שֶׁנָּפַל לְתוֹךְ גְּרִיסִין — אָסוּר, וְרַבִּי שִׁמְעוֹן מַתִּיר. וְהָא הָכָא דִּפְגַם מֵעִיקָּרָא הוּא, וּפְלִיגִי!
Rav Ḥagga raised an objection to the opinion of Ulla from a baraita: Forbidden wine that fell into lentils, or forbidden vinegar that fell into split beans, renders the food forbidden. And Rabbi Shimon deems them permitted. But here it is a case where the forbidden food detracted from the flavor of the dish at the outset, and the tanna’im disagree.
אָמַר עוּלָּא: חַגָּא לָא מִידָּע יָדַע מַאי קָאָמְרִי רַבָּנַן, תְּיוּבְתָּא קָא מוֹתֵיב? הָכָא בְּמַאי עָסְקִינַן? כְּגוֹן שֶׁנָּפַל לְתוֹךְ גְּרִיסִין צוֹנְנִין וְהִרְתִּיחָם, נַעֲשָׂה כְּמִי שֶׁהִשְׁבִּיחַ וּלְבַסּוֹף פָּגַם, וְאָסוּר.
Ulla said: Ḥagga does not know what the Sages say, yet he raises an objection? Here we are dealing with a case where the vinegar fell into the cold split beans and one subsequently heated them, in which case it becomes like a forbidden food that enhanced the flavor of the mixture and subsequently detracted from it, as vinegar enhances the flavor of cold split beans, and it is consequently forbidden according to Rabbi Meir.
וְרַבִּי יוֹחָנָן אָמַר: בְּפוֹגֵם מֵעִיקָּרָא מַחְלוֹקֶת.
And Rabbi Yoḥanan says: The dispute between Rabbi Meir and Rabbi Shimon is with regard to a case where the forbidden food detracts from the flavor of the permitted food from the outset.
אִיבַּעְיָא לְהוּ: בְּפוֹגֵם מֵעִיקָּרָא מַחְלוֹקֶת, אֲבָל הִשְׁבִּיחַ וּלְבַסּוֹף פָּגַם — דִּבְרֵי הַכֹּל אָסוּר, אוֹ דִּלְמָא בֵּין בָּזוֹ וּבֵין בָּזוֹ מַחְלוֹקֶת? תֵּיקוּ.
A dilemma was raised before the Sages: Does Rabbi Yoḥanan mean that the dispute is with regard to a case where the forbidden food detracts from its flavor from the outset, but if it enhanced it at first and subsequently detracted from it, everyone agrees that it is forbidden? Or, perhaps he means that the dispute is both in this case and in that case. The Gemara comments: The dilemma shall stand unresolved.
אָמַר רַב עַמְרָם: אֶפְשָׁר אִיתָא לְהָא דְּרַבִּי יוֹחָנָן, וְלָא תַּנְיָא לַהּ בְּמַתְנִיתִין?
Rav Amram said: Is it possible that there is substance to this statement of Rabbi Yoḥanan, i.e., that there is disagreement with regard to a case where the forbidden food detracts from the flavor of the permitted food from the outset, but it is not taught in the Mishna?
נְפַק דָּק וְאַשְׁכַּח, דְּתַנְיָא: שְׂאוֹר שֶׁל חוּלִּין שֶׁנָּפַל לְתוֹךְ הָעִיסָּה, וְיֵשׁ בּוֹ כְּדֵי לְהַחְמִיץ וְהֶחְמִיצָה, וְאַחַר כָּךְ נָפַל שְׂאוֹר שֶׁל תְּרוּמָה אוֹ שְׂאוֹר שֶׁל כִּלְאֵי הַכֶּרֶם וְיֵשׁ בּוֹ כְּדֵי לְהַחְמִיץ — אָסוּר, וְרַבִּי שִׁמְעוֹן מַתִּיר.
Rav Amram went out, examined the Mishna, and discovered that this dispute is taught in a mishna (Orla 2:8): In the case of non-sacred leaven that fell into the dough, and there is enough of it to cause the dough to become leavened, and the dough indeed became leavened, and subsequently leaven of teruma, or leaven of forbidden diverse kinds planted in a vineyard, fell into this dough, and there is enough of it to cause the dough to become leavened, the dough is forbidden, because the forbidden leaven is considered to have contributed to the process of the leavening. But Rabbi Shimon deems the dough permitted, because the additional leaven has a negative impact on the dough, which was already leavened.
וְהָא הָכָא, דִּפְגַם מֵעִיקָּרָא הוּא, וּפְלִיגִי!
Rav Amram comments: But here it is a case where the forbidden substance detracted from the flavor of the dough at the outset, and Rabbi Meir and Rabbi Shimon disagree, as a mishna that is not attributed explicitly to a tanna represents the opinion of Rabbi Meir.
אָמַר רַבִּי זֵירָא: שָׁאנֵי עִיסָּה, הוֹאִיל וּרְאוּיָה לְחַמֵּעַ בָּהּ כַּמָּה עִיסּוֹת אֲחֵרוֹת.
Rabbi Zeira said: Dough is different, because even if the additional leaven is detrimental to its flavor, in any event the dough is enhanced, since it is suitable for leavening several other batches of dough with it. The more it is leavened, the more it is enhanced in terms of this purpose.
תָּא שְׁמַע: שְׂאוֹר שֶׁל תְּרוּמָה וְשֶׁל חוּלִּין שֶׁנָּפְלוּ לְתוֹךְ הָעִיסָּה, בְּזֶה כְּדֵי לְהַחְמִיץ וּבְזֶה כְּדֵי לְהַחְמִיץ וְחִימְּצוּ — אָסוּר, וְרַבִּי שִׁמְעוֹן מַתִּיר. נָפַל שֶׁל תְּרוּמָה תְּחִלָּה — דִּבְרֵי הַכֹּל אָסוּר. נָפַל שֶׁל חוּלִּין וְאַחַר כָּךְ נָפַל שֶׁל תְּרוּמָה אוֹ שֶׁל כִּלְאֵי הַכֶּרֶם — אָסוּר, וְרַבִּי שִׁמְעוֹן מַתִּיר.
The Gemara suggests another source for the statement of Rabbi Yoḥanan: Come and hear that which is taught in a baraita: In the case of leaven of teruma and non-sacred leaven that fell into the dough, if this one was sufficient to cause the dough to become leavened and that one was sufficient to cause the dough to become leavened, and they both cause the dough to become leavened, it is forbidden. Rabbi Shimon deems it permitted. If the leaven of teruma fell in first, everyone agrees that it is forbidden. If the non-sacred leaven fell in first and subsequently the leaven of teruma or of diverse kinds that were planted in a vineyard fell in, this is also forbidden; but Rabbi Shimon deems it permitted.
וְהָא הָכָא, דִּפְגַם מֵעִיקָּרָא, וּפְלִיגִי! וְכִי תֵּימָא: הָכָא נָמֵי
The Gemara comments: But here it is a case where the forbidden substance detracted from the flavor of the dough from the outset, and they disagree. And if you would say: Here too,
כִּדְרַבִּי זֵירָא, תָּא שְׁמַע מִסֵּיפָא: הַיַּיִן שֶׁנָּפַל לְתוֹךְ עֲדָשִׁים, וְחוֹמֶץ שֶׁנָּפַל לְתוֹךְ גְּרִיסִין — אָסוּר, וְרַבִּי שִׁמְעוֹן מַתִּיר. וְהָא הָכִי נָמֵי דִּפְגַם מֵעִיקָּרָא, וּפְלִיגִי!
this can be explained in accordance with the explanation of Rabbi Zeira that dough is different because it is enhanced in any event, come and hear a refutation of that explanation from the latter clause of the same baraita: Forbidden wine that fell into lentils or forbidden vinegar that fell into split beans renders the food forbidden. And Rabbi Shimon deems them permitted. And here also, it is a case where the forbidden substance detracted from the flavor of the dough from the outset, and they disagree.
וְכִי תֵּימָא, הָכָא נָמֵי כִּדְשַׁנִּי לֵיהּ עוּלָּא לְרַבִּי חַגָּא: כְּשֶׁהִשְׁבִּיחַ וּלְבַסּוֹף פָּגַם, וּמִי פְּלִיגִי כְּשֶׁהִשְׁבִּיחַ וּלְבַסּוֹף פָּגַם? וְהָא קָתָנֵי: נָפַל שֶׁל תְּרוּמָה תְּחִלָּה — דִּבְרֵי הַכֹּל אָסוּר!
And if you would say: Here too, it can be explained as Ulla responded to Rabbi Ḥagga, that the baraita is referring to a case when the vinegar enhanced the flavor of the split beans and subsequently detracted from it, e.g., where it spilled into cold split beans and then they were heated, this cannot be said, as do they actually disagree in a case when the forbidden substance enhanced the flavor of the permitted food and subsequently detracted from it? But isn’t it taught in the first clause of the baraita that if the leaven of teruma fell in first, before the non-sacred leaven, everyone agrees that it renders the dough forbidden, as it enhanced the flavor of the dough at the outset, even though the flavor was subsequently detracted from by the non-sacred leaven?
אֶלָּא לָאו שְׁמַע מִינַּהּ, בִּפְגַם מֵעִיקָּרָא מַחְלוֹקֶת? שְׁמַע מִינַּהּ.
Rather, must one not conclude from it that the dispute is with regard to a case where the forbidden substance detracted from the flavor of the food from the outset? The Gemara affirms: Conclude from it that this is so.
הָנֵי תְּלָתָא בָּבֵי דְּקָתָנֵי, לְמָה לִי? בִּשְׁלָמָא בָּבָא דְּסֵיפָא, קָא מַשְׁמַע לַן: בְּפוֹגֵם מֵעִיקָּרָא מַחְלוֹקֶת. מְצִיעֲתָא נָמֵי, הִשְׁבִּיחַ וּלְבַסּוֹף פָּגַם — דִּבְרֵי הַכֹּל אָסוּר.
The Gemara asks: With regard to those three clauses that the baraita teaches concerning different cases, why do I need all three of them? Granted, the last clause, concerning the wine spilling into the lentils, teaches us that the dispute is with regard to a case where the forbidden substance detracts from the flavor of the food from the outset. The middle clause, with regard to the case where the leaven of teruma fell in first, also teaches a novel halakha, which is that in the case of a forbidden substance that enhanced the flavor of the food and subsequently detracted from it, everyone agrees that the mixture is forbidden.
אֶלָּא רֵישָׁא לְמָה לִי? הַשְׁתָּא, וּמָה סֵיפָא דְּלָא קָא מַשְׁבַּח כְּלָל, אָסְרִי רַבָּנַן, רֵישָׁא דְּקָא מַשְׁבַּח מִיבַּעְיָא?
But why do I need the first clause, concerning the case of non-sacred leaven and leaven of teruma falling into the dough together? It could have been inferred from the other two clauses that the dough is forbidden, in the following manner: Now that in the case of the last clause, where the forbidden substance does not enhance the permitted food at all, the Rabbis deem it forbidden, is it necessary to say that it is forbidden in the first clause, where the forbidden substance enhances the food’s flavor at first before detracting from it?
אָמַר אַבָּיֵי: רֵישָׁא לְרַבִּי שִׁמְעוֹן אִצְטְרִיךְ, וְהָכִי קָאָמְרִי לֵיהּ רַבָּנַן לְרַבִּי שִׁמְעוֹן: עִיסָּה זוֹ רְאוּיָה לְהַחְמִיץ בִּשְׁתֵּי שָׁעוֹת, מִי גָּרַם לָהּ שֶׁתַּחֲמִיץ בְּשָׁעָה אַחַת? אִיסּוּר.
Abaye said: The first clause is necessary to teach that Rabbi Shimon deems it permitted. And this is what the Rabbis said to Rabbi Shimon: This dough was fit to become leavened in two hours if the permitted leaven had fallen into it alone. What caused it to become leavened in one hour? The forbidden leaven. Therefore, the dough is forbidden.
וְרַבִּי שִׁמְעוֹן? כְּשֶׁהִשְׁבִּיחוּ, שְׁנֵיהֶם הִשְׁבִּיחוּ; כְּשֶׁפָּגְמוּ, שְׁנֵיהֶם פָּגְמוּ.
And Rabbi Shimon could respond that when the two types of leaven enhanced the flavor of the dough, they both enhanced it, not only the forbidden leaven; and when they subsequently detracted from it, they both detracted from it. Therefore, it is permitted.
לְרַבִּי שִׁמְעוֹן, לִיצְטָרֵף הֶיתֵּר וְאִיסּוּר בַּהֲדֵי הֲדָדֵי וְלִיתְּסַר!
The Gemara asks: Even according to the opinion of Rabbi Shimon, let the permitted leaven and the forbidden leaven combine together and render the dough forbidden, since Rabbi Shimon concedes that if the permitted food was initially enhanced by the forbidden substance it is forbidden.
רַבִּי שִׁמְעוֹן לְטַעְמֵיהּ, דְּאָמַר: אֲפִילּוּ אִיסּוּר וְאִיסּוּר נָמֵי לָא מִיצְטָרְפִי,
The Gemara responds: Rabbi Shimon conforms to his standard line of reasoning, as he says that even a forbidden substance and another forbidden substance do not combine to render a mixture forbidden. Accordingly, a forbidden substance and a permitted substance certainly do not.
דִּתְנַן: הָעׇרְלָה וְכִלְאֵי הַכֶּרֶם מִצְטָרְפִין, רַבִּי שִׁמְעוֹן אוֹמֵר: אֵין מִצְטָרְפִין.
The Gemara comments: This is as we learned in a mishna (Me’ila 18a): If orla and diverse kinds planted in a vineyard fell into a permitted substance, and neither one is sufficient in its own quantity to render the mixture forbidden, they combine to render it forbidden if together they are of a sufficient quantity. Rabbi Shimon says: They do not combine, and each forbidden substance is treated individually. Here too, since when the forbidden leaven enhanced the dough, it was not sufficient to enhance it by itself, the permitted leaven does not combine with it to render the dough forbidden.
הָהוּא עַכְבְּרָא דִּנְפַל לְחָבִיתָא דְּשִׁיכְרָא, אַסְרֵיהּ רַב לְהָהוּא שִׁיכְרָא. אַמְרוּהָ רַבָּנַן קַמֵּיהּ דְּרַב שֵׁשֶׁת: נֵימָא קָסָבַר נוֹתֵן טַעַם לִפְגָם אָסוּר?
§ The Gemara recounts an incident involving a certain mouse that fell into a barrel of beer. Rav deemed that barrel of beer forbidden. The Sages said before Rav Sheshet: Shall we say that Rav maintains that even in a case where the forbidden substance imparts flavor to the detriment of the mixture, it is forbidden? Presumably, the mouse imparted flavor to the detriment of the beer.
אֲמַר לְהוּ רַב שֵׁשֶׁת: בְּעָלְמָא סָבַר רַב נוֹתֵן טַעַם לִפְגָם מוּתָּר, וְהָכָא חִידּוּשׁ הוּא, דְּהָא מִימְאָס מְאִיס וּבְדִילִי אִינָשֵׁי מִינֵּיהּ, וַאֲפִילּוּ הָכִי אַסְרֵיהּ רַחֲמָנָא. הִלְכָּךְ נוֹתֵן טַעַם לִפְגָם נָמֵי אָסוּר.
Rav Sheshet said to them: Rav generally maintains that in a case where the forbidden substance imparts flavor to the detriment of the mixture, it is permitted. But here, in the case of a mouse, it is a novelty that the Torah prohibits the flavor from a mouse at all, as it is repulsive and people distance themselves from consuming it, and even so the Merciful One prohibits it. Therefore, although it imparts flavor to the detriment of the mixture, it is still forbidden.
אֲמַרוּ לֵיהּ רַבָּנַן לְרַב שֵׁשֶׁת: אֶלָּא מֵעַתָּה, לִיטַמֵּא לַח וְיָבֵשׁ, אַלְּמָה תְּנַן: מְטַמְּאִין לַחִים וְאֵין מְטַמְּאִין יְבֵשִׁים?
The Sages said to Rav Sheshet: If that is so, that the halakha with regard to a mouse is considered a novelty and is therefore understood to be more stringent than the norm, then a dead mouse should impart ritual impurity whether it is moist or dried out. Why did we learn in a mishna (Nidda 54b) that carcasses of creeping animals impart impurity when they are moist but do not impart impurity when they are dried out?
וּלְטַעְמָיךְ, שִׁכְבַת זֶרַע תְּטַמֵּא לַח וְיָבֵשׁ, אַלְּמָה תְּנַן: מְטַמְּאִין לַחִין וְאֵין מְטַמְּאִין יְבֵשִׁין?
Rav Sheshet responded: And according to your reasoning, in which you compare the halakhot of ritual impurity to forbidden foods, then with regard to semen, which is also repulsive, it should impart impurity whether moist or dried out. Why did we learn in a mishna (Nidda 54b) that semen imparts impurity when it is moist but it does not impart impurity when it is dried out?
אֶלָּא מַאי אִית לָךְ לְמֵימַר? ״שִׁכְבַת זֶרַע״ אָמַר רַחֲמָנָא, בִּרְאוּיָה לְהַזְרִיעַ. הָכָא נָמֵי, ״בְּמֹתָם״ אָמַר רַחֲמָנָא, כְּעֵין מוֹתָם.
Rather, what have you to say? With regard to the ritual impurity of semen, the Merciful One states: “The flow of seed” (Leviticus 15:16), meaning that the reference is to semen that is fit to fertilize. Here too, with regard to the ritual impurity of a mouse, the verse states: “When they have died” (Leviticus 11:32). The Merciful One states that the carcasses of creeping animals impart impurity only when they are similar to their state at time of their death, i.e., when they are still moist. Therefore, there is no contradiction to the claim that the prohibition against eating a mouse is a novelty and consequently applies even when it detracted from the flavor of the food into which it fell.
מַתְקֵיף לַהּ רַב שִׁימִי מִנְּהַרְדְּעָא: וּמִי מְאִיס? וַהֲלֹא עוֹלֶה עַל שֻׁלְחָן שֶׁל מְלָכִים! אָמַר רַב שִׁימִי מִנְּהַרְדְּעָא: לָא קַשְׁיָא, הָא בִּדְדַבְרָא, הָא בִּדְמָתָא.
Rav Shimi of Neharde’a objects to the assumption that a mouse is repulsive: And is it repulsive? But isn’t it served at the table of kings and considered a delicacy? Rav Shimi of Neharde’a said in clarification: This is not difficult. This statement, that a mouse is served as a delicacy, is stated with regard to a field mouse, and that statement, that it is repulsive, is stated with regard to a city mouse.
אָמַר רָבָא: הִלְכְתָא נוֹתֵן טַעַם לִפְגָם מוּתָּר, וְעַכְבְּרָא בְּשִׁיכְרָא לָא יָדַעְנָא מַאי טַעְמָא דְּרַב, אִי מִשּׁוּם דְקָסָבַר נוֹתֵן טַעַם לִפְגָם אָסוּר, וְלֵית הִלְכְתָא כְּוָותֵיהּ, אִי מִשּׁוּם דְקָסָבַר נוֹתֵן טַעַם לִפְגָם מוּתָּר, וְעַכְבְּרָא בְּשִׁיכְרָא אַשְׁבּוֹחֵי מַשְׁבַּח.
Rava said: The halakha is that if the forbidden substance imparts flavor to the detriment of the mixture, it is permitted. But with regard to a mouse that fell into a barrel of beer, I do not know what the reason was that Rav deemed it forbidden. I do not know whether it was because he maintains that if the forbidden substance imparts flavor to the detriment of the mixture it is forbidden, and if so, the halakha is not in accordance with his opinion, or whether it was because although he maintains that if the forbidden substance imparts flavor to the detriment of the mixture it is permitted, a mouse that falls into beer enhances its flavor.
אִיבַּעְיָא לְהוּ:
A dilemma was raised before the Sages: