Hard Cheese?

Is is true that one must wait 6 hrs after eating hard cheese?

Shalom!

Thank you for your question.

Indeed, just as one is required to wait between eating meat and dairy, one may also be required to wait a period of time after eating “hard cheese” before one is permitted to eat meat. This is because the taste and fatty residue of hard cheese lingers in the mouth for quite some time.

One must indeed wait six hours after eating hard cheese before eating meat.

There is much discussion as to which cheeses are to be considered “hard cheeses.  There are also cheeses in which the producers add ingredients to artificially speed up the process of aging, giving the cheese a taste of aged cheese. Therefore, Harav Fried Shelitta says for example, sharp cheddar, Emmental, Kashkabal, Maccabi blue, Original Tsafed cheese, Parmesan, Gouda, and Camembert, all have a taste of hard cheese, and many have taken on this stringency to wait six hours. 

One can be lenient with hard cheeses that was eaten when it was melted, such as on pizza, same too 'beshat hadchak' in a pressing situation like erev Shabbos one can be lenient, and the halacha is like when eating regular cheeses that one needs to do "Kinuach Ve'hadacha" as will soon be explained. Sefardic Jews do not generally keep the stringency of waiting six hours after hard cheeses and they merely  do "Kinuach ve'Hadacha" which means to eat a parve food like bread — not flour, dates, or leafy vegetables — and then to wash out one's mouth by drinking water and check that one's hands are clean from any dairy residue. They can then eat meat. Some are stringent to wait half an hour in between.

Rema, YD 89:2,11; Aruch Hashulchan , YD 89:11; Kitzur Shulchan Aruch 46:11; Kaf Hachaim , YD 89:46,48; Shach, YD 89:15; Taz , YD 89:4; Chochmat Adam 40:13; Yad Yehuda 89:26, 30; Darkei Teshuva 89:43