A Dairy Dilemma: Of Hard Cheese Complexities and Pizza Perplexities
One of the most famous associations with the upcoming holiday of Shavuos is the time-honored traditional custom of consuming dairy products; a minhag that is actually codified in halacha by the great Rema, Rav Moshe Isserles, the authoritative decisor for all Ashkenazic Jewry. He cites the ‘prevailing custom’ of eating dairy items specifically on Shavuos (Orach Chaim 494: 3).
As Shavuos is the only Yom Tov with such a directive to eat dairy products, it has become almost customary to pontificate on the topic of the halachic prohibition of mixing meat and milk and the mandated waiting period between them. Commonly addressed is the issue of hard cheese, the one dairy item that requires a similar six hour wait after consumption. This article attempts to focus on this key issue, and hopes to clear up any confusion on the topic.
This prohibition, although not mentioned in the Gemara, nevertheless dates back to the days of one of the greatest Rishonim, the Maharam M’Rottenberg (Shu”t Maharam M’Rottenberg 615). It seems that a while after he ate a piece of hard cheese he reported that he still felt the residue of the cheese in his mouth. He concluded that hard cheese shares similar properties with meat, and therefore maintained that is proper to wait a corresponding amount of time after eating such cheese before partaking in a meat meal, as one normally would between meat and dairy.
Although some authorities, including the Maharshal (Chullin, Ch. 8: 6 - who was extremely adamant that no one else has to wait due to the Maharam’s personal account), felt that the Maharam only mandated this for himself as a personal stringency, nevertheless, most decisors understood that the Maharam was introducing a new halacha, meant for all of Klal Yisrael. In fact, this is how the Rema rules (Yoreh Deah 89: end 2) and followed by virtually all later authorities that it is appropriate to wait a commensurate amount of time after eating hard cheese as one would wait after eating meat. However, it is important to note that the Rema himself qualifies that this halacha is intrinsically a chumra, and “one may not yell at anyone who does not follow it”.
Defining Hard Cheese
So, what exactly constitutes “hard cheese”, and thus necessitate a waiting period? As with many other halachic issues this is debated by the authorities. The accepted conclusion is that if one’s cheese fits into one or more of the following categories, then it would be considered “hard cheese” and thus requires a full waiting period:
- That it is aged six months (Parmesan would usually fit this category).
- It is “holey” as a result of production (As in “Holey Swiss Cheese!”).
- It is an extremely fatty and greasy cheese (Making the taste linger much longer).
- It is very strong and sharp (Limburger would be a good example of this).
Any cheese that does not meet at least one of these requirements, for all intents and purpose, is considered soft cheese and would only entail rinsing and cleaning of the mouth and hands before eating meat. This is the halachically mandated three-step process of kinuach - palate cleansing by eating a hard food item (ex. cracker), rechitza - hand washing, and hadacha - rinsing out of the mouth (Yoreh Deah 89: 2).
There are also those who follow the standard understanding of the Zohar (Parshas Mishpatim pg. 125: 1; cited in Biur HaGr”a, Yoreh Deah 89: 11) and wait one hour after eating any dairy product. Others customarily wait a half-hour, even though there is no actual specific known source for this. There are different rationales offered to explain this, most based on the Talmudic dictum of 'M'Palga Karov Karu Lay', 'From halfway is already considered close', meaning by waiting at least a half hour, it is as if one waited an hour. Additionally, there are those who are also strict with making Birchas HaMazon between a dairy and a meat meal. This is a tremendous dispute among halachic authorities, whether Birchas HaMazon is required after eating dairy foods before being allowed to eat meat. However, everyone agrees that it is indeed required if one actual hard cheese.
American and Yellow Cheese
The standard everyday cheeses used for grilled cheese, cheese toasts and pizza etc., [American, Yerushalayim, Mozzerella, Achuza, Gush Chalav etc.] would not seem to fit any of the above criteria and would not require a waiting period. And, in fact, the majority of contemporary authorities including Rav Aharon Kotler, the Chazon Ish, Rav Yosef Eliyahu Henkin, and Rav Moshe Feinstein rule that they are not considered halachic hard cheese. Rav Aharon related that most people nowadays do not know what real hard cheese is - a cheese that needs a “rib - eisen” (sharp grater) to cut off pieces. This would exclude our common cheeses, which can easily be pulled apart with our bare hands.
But if it’s so simple, why are there people who claim that one must wait after eating any sort of semi-hard cheese? Some even take this a step further and assert that it is Minhag Eretz Yisrael to wait a full six hours after eating pizza! What is the basis for such a position?
Minhag Eretz Yisrael?
The answer is based on a few enigmatic statements and responsa by several contemporary Gedolei Eretz Yisrael - Rav Shlomo Zalman Auerbach zt”l, Rav Yosef Shalom Elyashiv zt”l and Rav Shmuel Halevi Wosner zt”l.
Rav Shlomo Zalman Auerbach is quoted as ruling that one must wait the “full count” after eating the Israeli “Yellow Cheese” (Yerushalayim, Achuza, Gush Chalav, etc.). Rav Elyashiv and Rav Wosner both wrote responsa asserting similarly, that although not fitting the “hard cheese” criteria established by earlier authorities, nevertheless, one should still wait after these cheeses. Following their lead, several other authorities rule stringently as well. Consequently, many people, especially in Eretz Yisrael, maintain that one should wait after eating these cheeses.
However, if one would properly and thoroughly analyze the actual responsae of these Gedolim, he might conclude rather differently.
Finding out Rav Shlomo Zalman Auerbach’s authentic opinion is easier said than done. His opinion is quoted in no less than six separate sefarim (!) each relating conflicting and contradictory accounts of what his ruling actually was. The varied accounts include a lenient ruling on this topic, namely that these “yellow cheeses” are not considered hard cheese at all. It would therefore seem incongruous to be stringent exclusively on account of his reportedly machmir opinion.
Rav Wosner wrote his responsum on this topic (Shu”t Shevet Halevi vol. 2: 35) over forty-five years ago, stating that he personally was stringent, as (at the time) it was impossible to tell how long the cheeses were aged, since there was no manufacturer’s dating code printed on it. Since it was possible that the “yellow cheese” sold was aged for six months, he was machmir. However, nowadays, with the actual manufacturing date printed on every package, one can easily see if this cheese was aged for six months or not. In fact, more recent accounts of Rav Wosner’s opinion are that one does not have to wait after eating these “yellow cheeses”.
As for Rav Elyashiv’s responsum (Kovetz Teshuvos vol. 1: 58, 2), he definitely does rule that one must wait after eating such cheese. But his reasoning has puzzled many. Rav Elyashiv writes that one must be stringent, for the taste of these “yellow cheeses” are charif v’chazak - “sharp and strong”, terms which many would only associate with such strong cheeses as Limburger, Gold Cheddar, and Roquefort. Several later authorities, including Dayan Yisrael Yaakov Fischer zt”l, Ra’ava”d of the Bada”tz Eidah Charedis of Yerushalayim, have been perplexed by Rav Elyashiv’s words, since “yellow cheese” as we know it is neither sharp nor strong tasting. Interestingly, Rav Elyashiv's talmid muvhak Rav Yosef Efrati shlit”a writes (Shu”t Yissa Yosef, Orach Chaim vol. 2: 120) that Rav Elyashiv was stringent on “yellow cheese” only due to chumra and minhag, but held that m’ikar hadin one does not need to be stringent, and especially not in Chutz La’aretz. A similar sentiment was expressed by Rav Elyashiv’s son in law, Rav Ezriel Auerbach shlit”a (cited in Kuntress Sheilos U’Teshuvos Ketzaros B’Inyanei Issur V’Hetter pg. 20: 26), that even though m’ikar din one does not have to wait six hours for such cheeses, nevertheless, the minhag is still to wait.
Additionally, the Ben Ish Chai (Year 2: Parshas Shelach 15) over a hundred years ago, related that Minhag Yerushalayim is to be lenient with such “hard cheeses”. Moreover, as mentioned previously, the great Chazon Ish (cited in Orchos Rabbeinu vol. 3, pg. 77: 34 & Maaseh Ish vol. 5: pg. 22), final arbiter for much of Eretz Yisrael, ruled that nowadays, unless a cheese is aged for a full year, it is not considered “hard cheese”, and our “yellow cheeses” most definitely do not meet that criterion. In conclusion, although many in Eretz Yisrael are indeed stringent, the claim that the prevailing custom in Eretz Yisrael is to wait after “yellow cheese”, seems unsubstantiated. In fact, to quote mv"r Rav Yaakov Blau zt”l of the Bada”tz Eidah Charedis (to this author) on this topic, “to wait after yellow cheese is a chumrah bli ta’am”!
One of the recent sevaros that some claim to be machmir is that nowadays, with modern day chemicals etc., cheese can be “aged as if 6 months” in a relatively short time, and therefore the common “yellow cheese” is considered as if it was already aged 6 months, and consequently is halachic hard cheese.
The only problem with this beautiful logic is that it turns out that it is not exactly true! Several years ago, this author visited Tnuva’s main cheese-making factory in Israelwith three renowned kashrus and halachic experts, mv”r Rav Yonason Wiener, Rav Mordechai Kuber, and av”m Rav Manish Spitz. The Tnuva factory cheese specialists explained that this rationale does not hold water, and no additional chemicals or enzymes are used to “speed up” the basic cheese process, which is pretty much the same as it always was - sitting and ageing in a “salt water bath” for varying periods of time.
This is echoed by renowned kashrus expert Rav Yisrael Halevi Belsky zt”l, who was also the chief Posek for the OU (Shu”t Shulchan HaLevi vol. 1, Ch. 22, 1, Appendix s.v. gam), who uses very sharp terms to disprove the claims of the machmirim based on this erroneous rationale.
The Tnuva expert also informed us that the “yellow cheese” average processing time is only 18 days! This was later confirmed to this author by Rav Yaakov Blau zt”l, who headed the Bada”tz Eidah Chareidis Hashgacha. He added that standard “yellow cheese” is not aged for more than 25 days; nowhere near the six month mark. So even if the standard “yellow cheese” continues to age in the fridge and store shelf, it still has a long way to go to reach six months. This is why Rav Blau zt”l called waiting after its consumption a “chumra bli ta’am”!Asimilar ruling is cited by Rav Yisrael Yaakov Fischer zt”l after he learned the actual ins and out of “yellow cheese” processing, that there is no requirement to wait 6 hours after its consumption.
A Cheesy Hetter
Pizza and other melted cheese favorites, actually have an additional consideration to be lenient, even if actual hard cheese is used. The Yad Yehuda (Yoreh Deah 89: Pirush Hakatzar 26)rules that if hard cheese is melted, then it no longer retains the status of hard cheese and one is not required to wait after eating it. Although not unanimously accepted, (as the cheese’s taste remains unchanged even in its melted form), and there is some contemporary debate as to his exact intent, whether he was referring to cheese melted into or onto a food, nevertheless, several later authorities follow this ruling as well. They assert that one may definitely rely on this leniency regarding pizza since it is made with melted Mozzarella or “yellow cheese”.
In conclusion, although there are those who are stringent, on the other hand, there is strong basis for the generally accepted custom of not waiting six hours after grilled cheese and pizza. Yet, these days when it’s popular to use all types of exotic ingredients in gourmet cooking, it may be worthwhile to check your cheese packaging very carefully!
This article was adapted from an original Hebrew version, published in Kovetz Ohr Yisrael (vol. 62: Nissan 5771), and later in this author’s recent sefer M’Shulchan Yehuda. To obtain a copy of that full version, with its extensive sources and footnotes, or for any questions, comments or for the full Mareh Mekomos / sources please contact the author at: firstname.lastname@example.org.
This article was written L'zechus for Shira Yaffa bas Rochel Miriam v’chol yotzei chalatzeha for a yeshua teikif umiyad.
Rabbi Yehuda Spitz serves as the Sho’el U' Meishiv and Rosh Chabura of the Ohr Lagolah Halacha Kollel at Yeshivas Ohr Somayach in Yerushalayim. He also currently writes a contemporary halacha column for the Ohr Somayach website titled “Insights Into Halacha”. http://ohr.edu/this_week/insights_into_halacha/.
 This topic has been addressed by many - see the relevant commentaries to the Rema’s comment, especially the Machatzis Hashekel (Orach Chaim 494 s.v. h”h),Mishnah Berura, (ad loc. 14 & 15), and Kaf Hachaim (ad loc. 63), as well as Rav Moshe Feinstein zt”l’s Shu”t Igros Moshe (Orach Chaim vol. 1: 160), Rav Yaakov Kamenetsky zt”l’s Emes L’Yaakov on Tur and Shulchan Aruch(Orach Chaim 494 s.v. v’nohagin) and Rav Shlomo Zalman Auerbach zt”l’s Halichos Shlomo (Moadim vol. 2, Ch. 12, Orchos Halacha 1 and 35 and Dvar Halacha 10). There is even a recent sefer, Meta’amei Moshe, who lists 149 (!) different reasons for this minhag. Actually, several Rishonim, including the Kol Bo (72 and in Orchos Chaim - Tefillas HaMo'adim 13) and the Melamed HaTalmidim (pg. 121b) predate the Rema on this by several centuries, yet their mention is that of eating 'milk and honey' together in order to be yotzei the pasuk in Shir HaShirim (Ch. 4: 11)'dvash v'chalav tachas leshonecha', that the Torah is compared to milk and honey. Interestingly, other Rishonim, Rav Avigdor HaTzarfati (pg. 478) and Rav Yitzchak Isaac Tyrnau (Tirna) in his Sefer HaMinhagim (Hilchos Shavuos, Haghos 49) both write a different reason to eat milchigs on Shavuos. The pasuk that describes the holiday of Shavuos (Bamidbar, Parshas Pinchas Ch. 28, 26) states that one should bring a 'm incha ch adasha la'Hashem B ashavuoseichem' of which the first letters spell – 'meichalav' – with milk, implying that milk products should be eaten on Shavuos. This minhag is also mentioned by the Terumas Hadeshen (Leket Yosher pg. 103) and Maharil (Minhagim pg. 85), yet, it was not until the Rema codified this minhag in halacha that it became widespread. See also Rabbi Eliezer Brodt’s excellent recent 'The Mysteries of Milchigs' (Ami Magazine, May 12,, 2013 ppg. 88 – 93).
 This also cited by the Mordechai (Chullin 627) and the Hagahos Ashiri (glosses to the Rosh to Chullin 105). On a historical side note, the Maharam M’Rottenberg, was niftar in captivity after being unjustly imprisoned, in order to force the resident Jews to pay an exorbitant ransom to fill the Emperor's depleted coffers. The Maharam refused to allow himself to be ransomed, fearing that it would set a dangerous precedent of rulers holding Rabbis captive and forcing the unfortunate Jews to pay the price. Indeed, a short while after his passing, the Emperor attempted to do the same for the Maharam’s prized pupil, the Rosh, who only narrowly avoided capture, escaping to Spain.
 Issur V’Hetter (40: 8 s.v. vay), Beis Yosef (Orach Chaim 173 s.v. v’yesh machmirim), Darchei Moshe (Yoreh Deah 89: 2), Shach (ad loc. 17).
 Including the Shach (Yoreh Deah 89: 15), Taz (ad loc. 4), Pri Chodosh (ad loc. 16), Levush (ad loc. 2), Pri Megadim (ad loc. Mishbetzos Zahav 4 and Sifsei Daas 15 & 16), Machatzis Hashekel (ad loc. 15),Chochmas Adam (40: 13), Yad Yehuda (Yoreh Deah 89: Pirush HaKatzar 26), Chida (Shiyurei Bracha ad loc. 13), Atzei HaOlah (Basar BeChalav Ch. 3: 16), Chaguras Shmuel (Yoreh Deah 89: 18), Kitzur Shulchan Aruch (46: 11), Zivchei Tzedek (Yoreh Deah 89: 27), Aruch Hashulchan (ad loc. 11), Mishnah Berurah (Orach Chaim 494, Shaar HaTziyun 15), and Kaf Hachaim (Yoreh Deah 89: 46 and 47).
 Since the whole waiting period after hard cheese is based on the waiting period after meat, one may not wait less time after eating meat than he would after eating hard cheese - Shach (Yoreh Deah 89: 17).
 There are several halachic dispensations due to this. See for example, Maadanei Hashulchan (Yoreh Deah 89: Matamei Hashulchan 11).
 Issur V’Hetter, Shach, Pri Chodosh, Pri Megadim, Machatzis Hashekel, Chaguras Shmuel (ibid.), Ben Ish Chai (Year 2: Parshas Shlach 15). See Shu”t Shulchan Halevi (vol. 1:Ch. 25 s.v. u’beair).
 Issur V’Hetter, Taz, Pri Megadim, Atzei HaOlah, Zivchei Tzedek, Kaf Hachaim (ibid.), Chasam Sofer (Gloss to the Taz).
 Aruch Hashulchan (ibid.).
 Taz, Pri Megadim, Chaguras Shmuel, Kitzur Shulchan Aruch (ibid.), However, see Chasam Sofer, Atzei HaOlah, and Yad Yehuda (ibid.).
 The Zohar writes that everyone should wait between dairy and meat meals “one meal or one hour”. Although there are many interpretations offered for this enigmatic remark the most common one is that “one hour” is referring to mandating a waiting period of one hour even after eating dairy. Several authorities, including the Pri Chodosh, actually rule like this, and the Shulchan Aruch himself, in his Beis Yosef commentary, implied this way as well. Yet, when it came down to the practical ruling, the Shulchan Aruch did not mandate following the Zohar’s view. Other authorities who rule this way include the Pri Toar (ibid.), Shulchan Hatahor (Orach Chaim 173: 2), and Shu”t Kol Gadol (64). See also the Chida’s Shiyurei Bracha (Yoreh Deah 89: 13) and Shu”t Teshuvos V’Hanhagos (vol. 2: 390) who cite waiting an hour as a proper minhag. Yet, several authorities, including the Pri Chodosh, Pri Toar, Ya’avetz (Mor U’Ketziah, end Orach Chaim 173) and Aruch Hashulchan (Yoreh Deah 89: 11) qualify this ruling, that the one hour waiting period does not apply before eating fowl.
 Gemara Kiddushin (12a). There are many authorities who apply that klal to waiting a half hour after eating milchigs. See Matteh Reuven (186), Shu”t Maharshag (vol. 1: Yoreh Deah 13 s.v. amnam), Shu”t Divrei Chachamim (Yoreh Deah 1: 3 - quoting Rav Yaakov Kamenetsky zt”l), Shu”t Teshuvos V’Hanhagos (vol. 2: 390), Shu”t Shraga HaMeir (vol. 7: 105, 2), Netei Gavriel (Shavuos Ch. 31: 5), Shu”t Maa danei Melachim (85: 3), Shu”t Mishnah Halachos (vol. 10: 135), Halichos Shlomo (Moadim vol. 2: Ch. 12, footnote 49), Kovetz M’Beis Levi (on Yoreh Deah, pg. 35: 15), and sefer Minhag Yisrael Torah (Orach Chaim vol. 3, 494: 8 s.v. v’hinei).
The Magen Avraham (Orach Chaim 494: 6) rules that unless one ate hard cheese, which would require a full 6 hour wait, one need not have the dairy dishes and following meat dishes as separate meals. Thus, no Bentching is required. Many authorities follow the Magen Avraham’s ruling, and do not require Birchas Hamazon between a dairy and a meat meal. However, many other decisors, including the Shiyurei Knesses Hagedolah (ad loc. 3, cited in Darchei Teshuva Yoreh Deah 89: 14), and Shla"h (Shavuos, Ner Mitzvah, 8), disagree and mandate Bentching. The Ba’er Mayim Chaim (Parshas Vayera Ch. 18: 8, cited in Pischei Teshuva vol. 3, 287: 1) even maintains that the Magen Avraham's opinion must have been a printing mistake and that certainly one may not eat milk and meat as part of the same meal. To add another wrinkle, anyone who follows the Zohar’s view of waiting even after dairy would undoubtedly require Birkas Hamazon as well, as he maintains a higher degree of separation. Still, others, ardently defend the Magen Avraham’s position, and refer to this bentching as a “chumra yeseira”. Additionally, if it were truly a printing mistake, the Magen Avraham's son in law, Rav Moshe Yekusiel Kaufman Cohen, would have corrected it in his comprehensive sefer on halacha and minhag, Chukei Chaim. Yet, instead he rules exactly as his father-in-law did (Os Shin, 2, Dinei Chag HaShavuos: pg. 112a) "d'eino tzarich lehafsik b'Birkas Hamazon im aino ochel gevina kasheh, v'yizaher likach mapah acheres". This is also the final ruling of the Aruch Hashulchan (Yoreh Deah 89: 9) and Mishnah Berurah (Orach Chaim 494: 15). The chumrah to bentch after milchigs is also noticeably absent from the Chochmas Adam, who only cites the lenient ikar din. Still, many later and contemporary authorities rule that one should bentch after milchigs if at all possible, even though it may not be required by the letter of the Law.
 These Gedolim include Rav Aharon Kotler (cited in Kitzur Shulchan Aruch - Pfeiffer, on Basar Bechalav, vol. 1, Kuntress Habiurim pg. 138), the Chazon Ish (Orchos Rabbeinu vol. 3, pg. 77: 34 & Maaseh Ish vol. 5: pg. 22; he holds that the cheese must be aged for a full year to be considered hard cheese; for a possible explanation see Shu”t Maadanei Melachim 87 and 88), Rav Yosef Eliyahu Henkin (printed in the forthcoming Shu”t Gevuros Eliyahu vol. 2, Yoreh Deah 13; he holds one only needs to wait one hour), Rav Moshe Feinstein (cited in Shu”t Mishneh Halachos vol. 16: 9), the Ba’er Moshe (Pischei Halacha on Hilchos Kashrus pg. 108), Rav Yisroel Yaakov Fischer (Shu”t Even Yisroel vol. 9: 68), Rav Moshe Halberstam (cited in Shu”t Shav V’Rafa vol. 2: 26), Rav Ben Tzion Abba Shaul (cited in Sefer Hakashrus Ch. 10, footnote 122; he holds one only needs to wait one hour), Rav Chaim Pinchas Scheinberg (cited in Shu”t Shav V’Rafa vol. 2: 26; but maintains that this hetter is ‘b’dieved’), Rav Chaim Kanievsky (cited in sefer Nezer Chaim, Devarim Nochachim 124), Rav Ovadiah Yosef (Shu”t Yabea Omer vol. 6, Yoreh Deah 7: 4 and Shu”t Yechaveh Daas vol. 3: 58; he maintains that the whole din is essentially a chumrah), the Rivevos Efraim (cited in sefer Yigal Yaakov footnote 247), Rav Yisrael HaLevi Belsky (Shu”t Shulchan HaLevi vol. 1, Ch. 22: 1), Rav Asher Weiss (Minchas Asher al HaTorah, Shemos 61: 2), and Rav Dovid Feinstein (cited in Shu”t Vedibarta Bam 212, pg. 561 s.v. v’shamaati) .
 See Megillas Sefer (on Basar BeChalav 89: 5 s.v. uvagvinos) who proves this from Gemara Shabbos 121b.
Including the Maadanei Hashulchan (89: 30 and Shu”t Maadanei Melachim 89 & 90), the Mishneh Halachos (Shu”t vol. 16: 9), the Mishnas Yosef (Shu”t vol. 9: 184), and the Avnei Yashpei (Shu”t vol. 6, 112: 2), all of whom say that they follow the psak and rationales of these Gedolim to rule stringently with “yellow cheese”. The Minchas Yitzchok was also quoted as saying “yesh makom l’hachmir” (cited in Shu”t Teshuvos V’Hanhagos vol. 2: 388).
 SeferHakashrus (Ch. 10: 50, footnote 126) quotes Rav Shlomo Zalman as being stringent as the high fat percentages used in modern day “yellow cheese” causes the taste to linger much longer, similar to real hard cheese. Yet, Me’ohr HaShabbos (vol. 3, Teshuvos - 38: 1) cites a different (albeit ultimately erroneous - see later on) reason entirely why Rav Shlomo Zalman was machmir, as nowadays, with modern day chemicals etc., cheese can be “aged as if 6 months” in a relatively short time, and therefore the common “yellow cheese” is considered as if it was already aged 6 months.Yet, two other reliable sources,Rav Aharon Pfeiffer’s KitzurShulchanAruch(on Basar Bechalav, vol. 1, Kuntress Habiurim pg. 138), and in KovetzMoriah(Teves5756, PiskeiHalachosshel HaGaon Rav Shlomo Zalman) both report that Rav Shlomo Zalman maintained that “yellow cheese” is not considered hard cheese, and no waiting period is required. However, they relate that he personally was indeed stringent. The HalichosShlomo(Moadim vol. 2, Ch. 12; 13, footnote 50) tries to synthesize all these accounts and opines that Rav Shlomo Zalman originally only mandated waiting after real hard cheeses. But, in his later years, after “it became difficult to tell the differences between cheeses”, he became more stringent and ruled as well for others. The only problem with this is that in Shu”tShavV’Rafa(vol. 2: 26), Rav Shmuel Auerbach shlit”a is quoted as saying that his father, Rav Shlomo Zalman, held that there is absolutely no reason to be stringent with ‘yellow cheeses” at all. This is also similar to what Rav Shlomo Zalman's son-in-law, Rav Zalman Nechemiah Goldberg shlit”a personally told this author, that his shver was only makpid on real 'Kashkeval' cheese, and not the ‘yellow cheeses” at all. This was further confirmed to this author by his son, Rav Aharon Goldberg, who actually stayed with and ate with Rav Shlomo Zalman in his final years. On the other hand, to further complicate matters, Rav Ezriel Auerbach shlit”a, was quoted as saying that his father always waited six hours after eating “yellow cheeses”. Quite fascinatingly, in the recently published Maadanei Shlomo (on Dalet Chelkei Shulchan Aruch), Rav Shlomo Zalman’s talmid, Rav Yerachmiel Fried (author of Yom Tov Sheini Kehilchaso) writes that he noted to Rav Shlomo Zalman in his lifetime that there were differing accounts of his true psak [which he writes that he really held that there is no issue but nevertheless the minhag in his house was indeed to wait], and concludes that Rav Shlomo Zalman did this on purpose; that he did not want to take a public stance and be machria one way or the other.
 See Shu”t Mishneh Halachos (ibid. s.v. uvadavar) who although ruling to be machmir like Rav Elyashiv and the Shevet Halevi’s psak, nevertheless concludes that if there are manufacturing dates printed on the cheese packaging, one may indeed rely on them. See also Kovetz M’Bais Levi (vol. 6: 5755- from Rav Wosner’s Beis Medrash) who concludes that one does not need to wait after “yellow cheese”. This is also corroborated (in Shu”t Shav V’Rafa ibid.) by Rav Shmuel Berman, (the Steipler Gaon’s son in law) who related that Rav Wosner told him explicitly that one does not have to wait after such cheeses.
 Shu”t Even Yisrael (vol. 9: 68, 2), Shu”t Shulchan Halevi (vol. 1, Ch. 22: 1), Shu”t Shav V’Rafa (ibid., quoting Rav Yonason Wiener).
 The Chazon Ish’s nephew (and Rav Elyashiv’s son in law) Rav Chaim Kanievsky shlit”a (see footnote 14) rules this way as well. See Shu”t Maadanei Melachim 87 & 88 for a possible explanation.
 Interestingly, Rav Blau zt”l related that he personally was stringent on waiting six hours since his rebbi did, and therefore he was beholden to as well, even though he held that there was no halachic reason to do so.
 As cited in Halichos Even Yisroel (pg. 230, footnote 21 s.v. v’seeper). This was seemingly the basis of his psak in Shu”t Even Yisroel (vol. 9: 68).
Yad Yehuda (Yoreh Deah 89 Pirush Hakatzar 26). However, there is some contemporary debate as to his exact intent. See Rabbi Doniel Neustadt’s Daily Halacha Discussion (pg. 238: 22), Rabbi Binyomin Forst’s The Laws of Kashrus (Ch. 8: 2, 96), and Kovetz Ohr Yisrael (vol. 6: pg. 89, s.v. ulam).
Including the Ben Ish Chai (ibid.), Rav Yosef Shalom Elyashiv (ibid.), Badei Hashulchan (pg. 63, Biurim s.v. v’chein), Avnei Yashpei (ibid.), and the Maadanei Melachim (Shu”t 91). They all write that there is no difference between melted or solid hard cheese concerning the waiting period.
 Including the Atzei HaOlah (Basar BeChalav 3: 17, Chukei Chaim 16), Rav Dovid Feinstein (cited in Shu”t Videbarta Bam (end 212, s.v. v’shamaati), Rav Ezriel Auerbach (cited in Kashrus in the Kitchen Q & A - Teshuvos pg. 216), Rav Yisrael Halevi Belsky (Shu”t Shulchan HaLevi ibid. s.v. zos), and in Kovetz Pri Temarim (vol. 5, pg. 128: 82).
Disclaimer: This is not a comprehensive guide, rather a brief summary to raise awareness of the issues. In any real case one should ask a competent Halachic authority.
L'iluy Nishmas the Rosh HaYeshiva - Rav Chonoh Menachem Mendel ben R' Yechezkel Shraga, Rav Yaakov Yeshaya ben R' Boruch Yehuda.