We’re in chapter 7, whose subject is the gid hanasheh — the sciatic nerve, forbidden ever since Yaakov wrestled the angel (Bereishit 32:33). But by daf 97 the Gemara has widened its lens to a question that sits at the very heart of kashrut:
When a forbidden food is mixed or cooked into permitted food, when does the whole thing become forbidden — and when is the forbidden part “nullified” so the food stays permitted?
The idea powering the whole page is טַעַם כְּעִיקָּר — “taste is like the essence.” A forbidden food doesn’t forbid only through its physical substance; it forbids through the flavor it imparts (noten taam). That gives two very different ways a mixture can end up permitted:
97a builds the taste route; 97b builds the sixty route — and then stress-tests it on the gid, the udder, and a non-kosher egg.
The opening answer. Cheilev (forbidden fat) is different from the gid: its flavor permeates throughout the animal (mefaʿpeaʿ). The nerve barely gives taste of its own — a live debate on the previous daf — so the two aren’t automatically judged alike.
The challenge — R’ Yochanan and the goat. Rabba bar bar Chana reports a real case in the synagogue of Maon: a young goat was roasted together with its cheilev. R’ Yochanan ruled, “Peel it and eat it until you reach the fat.” Startling — if flavor permeates everything, the whole goat should be forbidden! The lesson: roasting doesn’t drive flavor through the way boiling does.
Three resolutions for why the goat wasn’t forbidden throughout:
Rava’s move — from a difficulty to a principle. Rava was troubled by a baraita: a pot used for meat shouldn’t be used for milk, and if it was, the milk is forbidden if the absorbed meat imparts flavor — likewise teruma absorbed in a pot renders later non-sacred food sacred if it imparts flavor. Fine for teruma, he says: a kohen may taste and check. But meat-in-milk — who tastes it? No Jew is allowed to. R’ Yochanan’s kilkhit ruling answers it: here too we rely on a gentile cook to report whether flavor was imparted.
The summary rule. Rava lays out the whole framework: sometimes we rely on a Jew tasting, sometimes on a gentile cook tasting, and sometimes — where neither works — on sixty.
Sorting the cases. When the foods are different types (min b’she’eino mino) and a permitted Jew can taste — e.g. teruma with non-sacred food — a Jew tastes. When the mixture is potentially forbidden to all Jews — meat-in-milk — a gentile cook tastes. But when they’re the same type (min b’mino) and flavor can’t be told apart, or no gentile taster is available, we fall back on sixty times as much permitted food.
The salted-thigh dispute. Thighs were salted with the gid still inside in the Exilarch’s house. Ravina forbids; Rav Acha bar Rav Ashi permits; asked to decide, Mar bar Rav Ashi says, “My father permitted it” — ruling leniently. Then Rav Acha bar Rav presses Ravina on his reasoning. The hinge is Shmuel’s “maliach k’rotcha, kavush k’mevushal“ (salted is like boiling-hot, marinated is like cooked). The Gemara reasons that “boiling-hot” here means like roasting, not like boiling — and since roasting doesn’t drive the nerve’s fat through the thigh, salting shouldn’t either. This is a difficulty (קַשְׁיָא) for Ravina’s stringency.
What joins the count of sixty? Rabbi Chanina: you measure against the broth (rotev), the sediment/spices (kipah), the pieces (chatichot), and the pot itself — all of it combines to nullify. (Two readings of “the pot”: the pot’s own volume, or what the pot absorbed from the permitted food.)
How to estimate the forbidden flavor. R’ Abbahu in the name of R’ Yochanan: assess the forbidden food “as though it were onion or leek (kaflot)” — gauge how strongly that would flavor the dish. R’ Abba pushes back: why not assess it as pepper, which never nullifies (not even in a thousand)? Abaye answers: the Sages determined nothing imparts flavor more strongly than onion and leek — so that’s the yardstick.
The tricky trio — gid, udder, egg. Rav Nachman gives the counting rules: a gid is nullified in sixty and is not itself counted; an udder (kachal) cooked with meat — the milk is nullified in sixty and the udder is counted with the meat; a non-kosher egg is nullified in sixty and is not counted.
The udder, taken apart. R’ Yitzchak son of Rav Mesharshiyya sharpens it: even with sixty-to-one, the udder itself stays forbidden (the meat drives flavor into the milk inside it), and if that udder later falls into a second pot it forbids that pot too — unless there’s sixty against the whole udder. Rav Ashi recalls a dilemma from Rav Kahana’s study hall — do we measure against the udder’s whole volume or only the milk that came out? — and the Gemara concludes we measure the whole thing, because the Sages effectively treated the udder like an intrinsic piece of non-kosher meat (chatichah d’neveilah).
Does an egg even give taste? Rav Idi bar Avin needles Abaye: people call something tasteless “mere egg-water (mei beitzim)” — so how can a forbidden egg impart flavor at all? Abaye begins to answer (“here we are dealing with…”) — and the sugya carries into 98.
| Term | Meaning |
|---|---|
| גִּיד הַנָּשֶׁה — gid hanasheh | The sciatic nerve, forbidden to eat (Bereishit 32:33). Gives little taste of its own. |
| חֵלֶב — cheilev | Forbidden fats. Strong flavor — the paradigm food that “gives taste” and permeates (mefaʿpeaʿ). |
| טַעַם כְּעִיקָּר — taam k’ikar | “Taste is like the essence” — forbidden flavor forbids, not just substance. The core idea of the daf. |
| נוֹתֵן טַעַם — noten taam | “Imparts flavor.” Whether a food noten taam decides whether it forbids the mixture. |
| קַפִּילָא אֲרַמָּאָה — kapeila arma’a | A gentile cook — relied on to taste a doubtful mixture that no Jew may taste. |
| בִּיטּוּל בְּשִׁישִׁים — bittul b’shishim | Nullification in sixty. The fallback ratio when taste can’t be assessed. |
| מִין בְּמִינוֹ / מִין בְּשֶׁאֵינוֹ מִינוֹ | “Type with its own type” vs. “type with a different type” — same food (flavor undetectable → use the ratio) vs. different foods (a taster can help). |
| מָלִיחַ כְּרוֹתֵחַ / כָּבוּשׁ כִּמְבוּשָּׁל | “Salted is like boiling-hot / marinated is like cooked” — Shmuel; can salting transfer flavor like heat? |
| רוֹטֶב / קִיפָּה / חֲתִיכוֹת | Broth / sediment (spices & bits) / pieces — all counted toward the sixty, along with the pot. |
| כָּחָל — kachal | The udder — meat that contains milk; special counting rules, treated like intrinsic non-kosher meat. |
| בָּצָל וְקַפְלוֹט — batzal v’kaflot | Onion and leek — the Sages’ benchmark for the strongest flavor-giver, used to estimate a forbidden food. |
| חֲתִיכָה דִּנְבֵלָה — chatichah d’neveilah | “A piece of carrion” — a piece treated as intrinsically forbidden; how the Gemara ends up classifying the udder. |
| מֵי בֵּיצִים — mei beitzim | “Egg-water” — proverbial for tasteless; raised to question whether an egg imparts flavor at all. |
A field guide to every sage named on 97, using the title tells (Rav = Babylonian Amora; Rabbi = Tanna or Eretz-Yisrael Amora; Rava/Ravina live in Bavel despite the -a ending). Where a minor figure’s details are thin, that’s flagged rather than invented.
A forbidden food is judged by the flavor it gives — so a mixture is permitted either when a reliable taster tastes nothing forbidden, or, when tasting can’t help, when there is sixty times more permitted food than forbidden.
Tomorrow (6 Aug 2026): Chullin 98 — Abaye finishes the egg-water answer, and the sugya presses on into the mechanics of bittul b’shishim and the rule of the “piece that itself becomes forbidden” (chatichah naʿasit neveilah).