New York (VINNEWS/Rabbi Yair Hoffman)  There is a well-known minhag, brought down in the Rema (Orach Chaim 494:3), to eat milchig foods on Shavuos. Many reasons have been offered. Among the most famous is the one cited in the Mishnah Berurah (494, sk 12) in the name of earlier sources: when Klal Yisrael stood at Har Sinai and received the Torah, they received with it the laws of basar b’chalav. Until then, their utensils were not kashered for meat, and they could not slaughter, salt, nor prepare meat in time for the seudah. They therefore ate milchig on that first Shavuos. What more fitting moment, then, to sit down once again and review — or perhaps to learn anew — the halachos of meat and milk that were given to us on this very day?  Perhaps this might be good material for Shavuos night learning.  Much of this was prepared with the aid of a remarkable sefer called Aizer LaShulchan.  So, even though it is Shavuos, in the spirit of Pesach, let’s ask four fundamental questions. [Feel free to print out and study].

• First: did the meat and milk in fact mix, and through what mechanism?
• Second: did taste actually transfer from the one to the other at the point of contact?
• Third: was that taste a nosein ta’am l’shvach — a flavor that improves — or nosein ta’am lifgam — one that spoils?
• And fourth: was the taste that traveled a full, first-degree flavor, or was it only nat bar nat — a secondhand taste of a taste?

Each of these four questions contains its own sugya, its own debates of the Rishonim, and its own practical applications. The Beis Yosef, the Rema, the Shach, the Taz, the Magen Avraham, and the Pri Megadim build the entire structure of Yoreh Deah simanim 87 through 97 upon them.

Question #1: The Mechanism — How Did They Mix?

Cold Touching Cold

When a piece of meat and a piece of cheese come into contact while both are cold, nothing is absorbed from one into the other. A simple rinse suffices (see Shulchan Aruch Yoreh Deah 91:1). Should cold milk fall upon cold meat that has cracks or grooves, the milk may need to be scraped out of those grooves, as the Mechaber elaborates in YD Siman 91:7. Even where scraping is required, the concern is only d’rabbanan; min haTorah, only meat and milk actually cooked together are forbidden.

Meat and cheese resting beside one another — even touching — when both are cold are wholly permitted. There is not even a rabbinic concern, since the fire is not involved. But when one is hot and the other cold, the matter is disputed. The Rema (105:3) and the Shach (sk 9) hold that one peels off the k’dei klipah — the outer layer — of the cold piece. The Taz (sk 5) is more stringent and forbids the entire piece where there is no significant hefsed merubeh.

Bishul — Cooking Together

Meat and milk cooked together are forbidden min haTorah. “Bishul” in this context means cooking together in a kli rishon — the primary vessel on the fire — or even in a kli rishon that has been removed from the flame, so long as it remains yad soledes bo, the temperature from which the hand instinctively recoils.

Where one of the two foods is hot from a kli rishon and the other cold, the principle is tata’ah gavar — the lower item dominates (Chullin 91b; Shulchan Aruch 91:4). Cold milk that falls into hot meat renders the meat forbidden. Hot meat that falls onto cold milk leaves the meat muttar with the removal of klipah, since only a slight surface flavor seeps in.

Iruy — Pouring from a Pot

The Rishonim disagreed whether iruy mi-kli rishon — pouring from a hot vessel that was on the fire — cooks the food onto which it lands as the kli rishon itself does. The accepted halachah is that an unbroken stream of pouring does cook the lower food and forbids it min haTorah.

Where the stream has been broken, the Shach holds the flavor still penetrates fully though it does not technically cook, leaving only an issur d’rabbanan. The Magen Avraham holds that once the stream is broken, klipah suffices, and even that is only a chumra d’rabbanan.

Kli Sheni

The Gemara establishes that a kli sheni — a secondary vessel into which food has been transferred — does not cook (Shabbos 40b; Chullin 108a). Some Rishonim hold that since it does not cook, it also does not transfer flavor at all.

The Rashba and others hold that while it does not cook, it does transfer flavor. The Shulchan Aruch ruled stringently l’chatchilah and leniently b’di’eved in pure cold contact. The Maharshal maintained that a kli sheni transfers no flavor whatsoever, while the Taz ruled not to be lenient absent hefsed merubeh.

The Shach brings the many Rishonim who hold that a kli sheni transfers no taste, and rules accordingly: absent significant loss, one is machmir to peel klipah in earthenware vessels and in the food itself. The Rema is lenient — a kli sheni transfers no flavor at all — while the Maharshal is stringent, and the Magen Avraham treats this stringency as if it were a Torah-level concern for one who actively cooks. Some authorities further hold that even a solid piece of food sitting within a kli sheni absorbs and transfers as it would in a kli rishon — davar gush being a sugya of its own.

Tzli — Roasting

When meat is roasted with cheese, the absorbed taste spreads only k’dei klipah — the depth of a thin peel. But where the meat is fatty (shamen), the entire piece of cheese soaks up flavor, and the meat soaks up flavor in return, so that the issur disperses throughout the entire piece. The Taz disagrees on this point. Where the issur has dispersed, one requires shishim — sixty times the volume of permitted food — to be mevatel the forbidden taste. The same applies in reverse where it is the cheese that is fatty.

The Rema rules that ein anu beki’in — we are no longer expert in determining when meat is considered fatty — and we are therefore always stringent to require shishim for any flavor that comes through tzli, even absent hefsed merubeh. Leniency is permitted only in cases of real loss. The Shach (105:17–18) clarifies that even with this chumra, we do not extend it to claim a lack of expertise regarding sidkei basar — the cracks in fatty meat themselves.

All of the above applies where both pieces were hot, or where the lower piece alone was hot, since the roasting then enabled the meat to take in flavor through hadachah or absorption. Where only the upper piece was hot, klipah suffices, just as in bishul.

A forbidden item can sometimes be returned to a permitted state through tzli after the fact. This avenue is open only when the item itself is not the forbidden substance but merely carries an absorbed forbidden flavor that roasting can draw out. Where the item itself is the issur — for example, where permitted meat was cooked together with non-kosher meat and never rinsed — tzli cannot help. However, where the absorbed forbidden taste is a fatty substance, the flavor can be drawn out through tzli just as it would from any forbidden item, and the same applies even by bishul.

Regarding basar b’chalav specifically — a piece of meat that absorbed milk flavor through a permitted means — the Shach is stringent and forbids it even through tzli in fatty cases, though the milk’s taste has not actually dispersed through the meat. The Taz holds there is no distinction here from other forbidden foods, since meat which was cooked without milk is not itself basar b’chalav mamash. Even with the Shach’s chumra in fatty matter, the Shach (105:17–18) himself does not extend the principle of ein anu beki’in to the cracks in the meat.

The poskim further disagreed whether tzli even rises to the level of bishul for basar b’chalav. Some hold the issur is min haTorah, while others rule it is only d’rabbanan, since the pasuk specifies cooking and not roasting.

Tigun — Frying

The poskim likewise disagreed whether tigun — frying — qualifies as bishul for basar b’chalav. The Pri Megadim’s position is to be machmir absent hefsed merubeh. Frying in a substantial quantity of oil, where the food sits within the oil itself, disperses absorbed flavor throughout all of the oil exactly as cooking does. Where the oil is minimal, the rule turns on whether the piece was actually fried in oil. According to Rashi, the juice that emerges from the meat follows the rules of broth in bishul. According to Rabbeinu Tam, the distinction depends on whether broth actually runs out of the meat, and the case is treated either as bishul or as tzli — even with only a small amount of oil involved, as the Beis Yosef explains in the relevant passage of siman 105.

Melichah — Salting

Salting follows the rules of tzli and produces both absorption and emission of flavor. With regard to basar b’chalav, however, melichah is forbidden only mid’rabbanan, since it is not the ordinary mode of cooking (see Chullin 97b; Shulchan Aruch 91:5). The reach of the forbidden flavor is k’dei klipah. In fatty cases, the issur spreads through the entire item and shishim is required. The Shulchan Aruch holds that even in fatty cases the spread is only klipah, but the Shach (105:28) holds that in melichah we do not invoke the leniency that removes the basic prohibition.

In our day, salting a minimal amount — a k’mo nemalah, an ant-like quantity — is not considered like tzli. But where one salts in this way in order to cook the meat immediately, the Rema (91:5) writes to be stringent. Anything salted k’melichah l’kadeirah — the salting done to draw out blood for cooking, even a light salting — falls under this rule. The Beis Yosef discusses the matter in siman 105, in the passage beginning V’inyan tzli.

The forbidden taste seeps into every crack, and shishim is required to be mevatel it. The Shulchan Aruch holds that even in hefsed merubeh one is machmir in melichah, and where the permitted food has absorbed flavor, the entire permitted food is forbidden, since it has mingled with the gufo of the issur. The Shach (105:28) holds that in melichah we do not say the permitted food removes the underlying prohibition.

Kevishah — Pickling

Pickled food has the halachic status of cooked food: kavush k’mevushal (Chullin 97b; Shulchan Aruch 105:1). Meat that was pickled in milk renders both wholly forbidden. Kevishah is defined as twenty-four hours of soaking together. Some hold that pickling in a davar charif — a sharp substance — produces the same effect after only twenty-four minutes. With brine, all agree that the entire item is forbidden in the time it takes for fire to bring the brine to a boil — the same span required to peel off the outer layer immediately. Regarding vinegar, some hold that brine acts faster; the Shach holds that the kulah applies only to drawing flavor out, not to joining two flowing substances together. Pickling in items forbidden min haTorah produces a Torah-level prohibition; for basar b’chalav, kevishah is only d’rabbanan, since it is not the normal mode of cooking.

Davar Charif — A Sharp Item

A davar charif — onion, garlic, radish, and the like — draws absorbed flavor outward through forceful pressure, such as the pressure of a knife (duchka d’sakina). When one cuts an onion with a fleishig knife, the absorbed flavor disperses through the entire onion. The spread of forbidden taste through a cold item is normally limited to klipah, leaving the remainder muttar; but the Rema is stringent and forbids the entire item ab initio (see Yoreh Deah 96).

Question #2: Did Taste Actually Transfer?

Where meat and milk became mixed but were not cooked, they are not rendered forbidden unless taste can actually be discerned in the mixture. Where meat was cooked in milk and the matter is tested through tasting, and a kafeilah — an expert chef or taster — reports no taste of milk, the meat is permitted. The Shulchan Aruch (98:1) defines who qualifies for this purpose. The Rema holds that in our times we no longer rely on tasting altogether. Instead, if there is shishim of the meat against the milk, the meat is muttar. Chazal established this ratio on the assumption that taste will not register where the permitted food outweighs the forbidden by sixty to one.

The reason tasting is admissible even where both flavors are of the same min is explained by Rabbi Akiva Eiger in his Teshuvos (Mahadura Kama, siman 6). All the Rishonim agree that without permitted substance to be mevatel the issur, the food is forbidden, since one does not rely on the absence of taste. The Rema’s position in our day is that the heter operates through bittul, since Chazal’s measure of shishim means that flavor is not felt once the permitted food outweighs the issur sixty to one.

Chaticha Na’asis Neveilah

Where a k’zayis of meat was cooked in milk and itself became a chaticha na’asis neveilah — a piece that has become wholly forbidden — and that piece was then cooked with other meat, shishim is required against the entire piece, not merely against the half-zayis of cheese that originally caused the prohibition. With other issurim — for example, where a k’zayis of meat and a half-zayis of forbidden meat are cooked together with other meat — the Rishonim divide. Some say shishim is measured against the whole k’zayis of meat that absorbed the issur, while others hold that the rule of chanan does not apply, and shishim against the half-zayis itself suffices (see Chullin 100a).

Im Yesh L’Mochaso

Where that piece was then cooked a second time with shishim against the original forbidden item, the Gemara records divergent views. According to those who reject chanan, where the absorbed flavor yesh l’mochaso — can be squeezed back out — the first piece reverts to its original permitted status. According to those who hold asur l’mochaso — that the absorbed flavor may not be squeezed out because the permitted food has taken on forbidden taste — the piece is still permitted, but on different grounds. The halachah is the subject of dispute, and the poskim’s practical psak is to be stringent. The view that does apply chanan also holds asur l’mochaso, as the Gemara works out in Chullin 108a. The Gemara there asks how one could possibly say yesh l’mochaso: what is unique about a chaticha na’asis neveilah? After all, the very name “chaticha na’asis neveilah” arose through bishul itself, and so the same should permit yesh l’mochaso. See further in the Pri Megadim (siman 92:10).

The Acharonim disagreed as to why asur l’mochaso. The Maharam of Lublin and others held that because the forbidden flavor was originally absorbed in that piece, it is forever “that piece.” Until squeezing has removed the issur, it retains its forbidden status — and so even if it later absorbed something else and the original flavor was wholly destroyed, the forbidden taste may yet remain. The Pri Megadim (siman 92:11) rules clearly that as long as no one has actually tasted any flavor, we treat it as if no flavor is there; once a kapelan has tasted and there is no flavor of the issur, the halachah follows the Maharam of Lublin.

Question #3: L’Shvach or Lifgam?

A forbidden taste that has gone bad inside the permitted food does not render the food forbidden: nosein ta’am lifgam mutar (Avodah Zarah 67b; Shulchan Aruch 103:5). When something assur was cooked in a pot and twenty-four hours have since passed without use, the absorbed flavor is considered spoiled. Permitted food cooked in that pot afterward is not forbidden. The same applies to basar b’chalav: meat cooked in a milchig pot twenty-four hours after milk was last cooked in it is not forbidden — provided the other relevant conditions are met.

Where one has a pot whose history is unknown — where it is uncertain whether the pot has been used within the past twenty-four hours — the assumption is that it has not been used bnos yomo and is therefore eino ben yomo.

Davar Charif Once More

The poskim disagreed whether a davar charif retains its eino ben yomo leniency after twenty-four hours. The accepted view is to be stringent, since a sharp substance replaces the spoiled flavor with a fresh and improved one — achaliyei l’shvach. One who cooks a sharp food in a pot eino ben yomo therefore renders the food forbidden k’dei klipah. Likewise, one who cuts a davar charif with a forbidden knife eino ben yomo renders the sharp food forbidden k’dei klipah. Some hold the entire item is forbidden.

Question #4: A Full Ta’am or Only Nat Bar Nat?

Meat cooked together with milk — or cooked in a pot in which milk had just been cooked within the time that taste still transfers — receives a full, first-degree taste of the milk and is forbidden, absent shishim. Meat cooked together with a davar parve that was earlier cooked in a milchig pot, however, is not forbidden. This is nat bar nat: the milk gave taste to the pot, the pot gave taste to the pareve food, and the pareve food alone is what came into contact with the meat. The transfer is one step too removed to forbid (see Shulchan Aruch 95:1).

Absorbed Flavor Without Liquid

Where forbidden flavor has been absorbed into something — food or vessel — and that item then comes into contact with a permitted item without any liquid between them, even with both hot, the permitted item is not necessarily rendered forbidden. Absorbed taste does not always emerge without a liquid medium. The matter turns on three variables: whether the absorbed flavor is regular taste or actual fatty substance (shumno); whether the flavor is absorbed within food or within a vessel; and whether the item now being touched is food or a vessel.

A Quick Reference

What follows is a practical summary of the rules for how absorbed taste spreads without liquid:

Flavor absorbed in food → touching food: If the flavor is lean, the touched food is permitted (Shulchan Aruch 105:7). If the flavor is fatty, the touched food is forbidden (Shulchan Aruch 105:7).

Flavor absorbed in food → touching a vessel: If the flavor is lean, the vessel is permitted (Taz 105:16). If the flavor is fatty, the matter is disputed. The Beis Hillel (92:15; 105:15) is lenient; the Bach (Yoreh Deah, Beis Shmuel siman 105) disagrees, and many Acharonim are stringent — see Darkei Teshuvah 105:143.

Flavor absorbed in a vessel → touching food: If the flavor is lean, one removes klipah (Shach 105:23). If the flavor is fatty, the matter is doubtful (Shach there). The stricter view applies specifically to fatty substance in oily food where there is no certain absorbed flavor; where there is moisture and even a small amount of fat throughout, and one wishes to peel off only k’dei klipah l’chatchilah, the Shach’s reasoning extends further, as the Maharshal questioned the Maharsha and as the Shach writes end of siman 94.

Flavor absorbed in a vessel → touching another vessel: If the flavor is lean, the second vessel is muttar (Rema 92:8). It is even permitted l’chatchilah, though some Acharonim forbid l’chatchilah. If the flavor is fatty, it is likewise permitted, as is clear from the Taz (92:3) where he speaks of mafladin — that there is fat present — and yet permitted vessel-touching-vessel. The Pri Megadim writes similarly (105:22).

Issur itself (not absorbed flavor) → touching a vessel: If lean, some hold one removes klipah — see the Chazon Ish on the Shach (94:8). If fatty, the vessel is forbidden, since those who were lenient permitted only what sat in oil; with an actual fatty substance, the matter is wholly forbidden.

Issur itself → touching food: If lean, hadachah suffices (Shulchan Aruch 105:4). If fatty, the food is forbidden (Shulchan Aruch 105:5).

A Closing Thought

This is the skeleton of a sugya that fills many pages of Mechaber, Ramah, Shach, Taz, Pri Megadim, and acharonim. Every word above opens onto further machlokes, further chumros, further kulos in cases of hefsed merubeh. The Rema (Yoreh Deah 87:3) reminds us that the prohibition of basar b’chalav is so foundational that the very utensils used for the one must be kept entirely separate from those used for the other — a separation that, more than perhaps any other halachic detail, marks the daily rhythm of our homes.

When we sit down  on Shavuos, the milchig spread on the table is not only a remembrance of how we ate on the morning the Torah was given. It is testimony that the Torah we received included these very halachos.

The author can be reached at [email protected]