The waiting period between meat and milk (the six hours), meat left between the teeth, the milk→meat order, and separating the table (Shulchan Aruch, Yoreh De'ah 89 — 4 seifim)
אָכַל בָּשָׂר, אֲפִלּוּ שֶׁל חַיָּה וְעוֹף, לֹא יֹאכַל גְּבִינָה אַחֲרָיו עַד שֶׁיִּשְׁהֶה שֵׁשׁ שָׁעוֹת. וַאֲפִלּוּ אִם שָׁהָה כַּשִּׁעוּר, אִם יֵשׁ בָּשָׂר בֵּין הַשִּׁנַּיִם צָרִיךְ לַהֲסִירוֹ. וְהַלּוֹעֵס לְתִינוֹק צָרִיךְ לְהַמְתִּין.
The waiting period after meat: One who has eaten meat — even of a wild animal or fowl — may not eat cheese after it until he has waited six hours. And even if he has waited the required time, if meat remains between the teeth, he must remove it. And one who chews [meat] for [feeding to] a child must [likewise] wait. (Gloss of the Rama: if he then finds meat between his teeth and removes it, he must rinse his mouth before eating cheese. And some say that it is not necessary to wait six hours, but that as soon as one has cleared the table and recited birkat ha-mazon, it is permitted by means of kinu'ach and hadachah; the widespread custom in these lands is to wait one hour after meat and then eat cheese, provided one has also recited birkat ha-mazon after the meat. And some are scrupulous to wait six hours after meat before cheese, and that is the proper way to act.)
Shulchan Aruch, Yoreh De'ah 89:1LEVEL 01
Hebrew text of the Mechaber and the Rama with a flowing English translation. The 4 seifim, the two reasons for waiting, the one hour or the six hours, meat between the teeth, the milk→meat order, separating the table, key concepts and practical cases.
📖 StudyLEVEL 02
In-depth pilpul: the sugya of Chullin 105a, the two te'amim (Rambam vs Tur/Rashi), the machloket over the one hour and birkat ha-mazon (Tosafot/Rabbenu Tam against Rif/Rambam), hard cheese, the Zohar, kinu'ach and hadachah, חקירות and נפקא מינות, debates among Shach / Taz / Pitchei Teshuva.
📖 StudyLEVEL 03
Comparative tables (six hours / one hour / immediate), golden rules, classic pitfalls (meat between the teeth, hard cheese, the milk→meat order), mnemonic and memorization of the 4 seifim.
📖 StudyLEVEL 04
The practical halacha according to the Shach, Taz and Pitchei Teshuva, then the Sephardic poskim (Yabia Omer, Yalkut Yosef, Or LeTzion) and the Ashkenazi poskim (Iggrot Moshe). Note: the Shulchan Aruch HaRav does not cover this siman — psak level, not "Daat HaRav."
📖 StudyThe Shulchan Aruch (YD 89:1) rules that one must wait six hours after meat before eating cheese or any dairy food. The Rama also reports a more lenient Ashkenazi practice (one hour, after clearing the table and reciting birkat ha-mazon), but concludes that « some wait six hours, and that is the proper way to act ». The Sephardic practice, and that of many Ashkenazim today, is to wait six hours. For the exact duration you must observe (according to your community), consult your Rav.
The Talmud (Chullin 105a) and the Rishonim give two reasons for waiting after meat: the fatty taste of meat lingers a long time in the mouth (Rashi/Tur), and small pieces of meat can remain between the teeth (Rambam). Neither of these factors exists after milk: this is why seif 2 permits eating meat immediately after cheese, provided one rinses the mouth (kinu'ach) and inspects it — except after a hard cheese, in which case one waits as one does after meat (Rama). For the practical halacha, consult your Rav.
Yes. Seif 4 (with the Rama's gloss) teaches that it is forbidden to cut cheese — even cold — with a knife normally used for meat, and vice versa. The Rama concludes that « all Israel has already adopted the custom of having two knives, of marking one as a sign — the custom is to mark the dairy one — and one must not alter the custom of Israel ». One must also clear the table of bread crumbs and not eat cheese on the tablecloth that was used for meat. For the practical halacha, consult your Rav.