Several weeks ago, we had discussed that if one eats a Kezayit (an olive’s volume) of food whose blessing is “Shehakol” within approximately four-and-a-half minutes, one must recite the “Boreh Nefashot Rabbot” after-blessing (printed in most Siddurim).
Furthermore, we have explained that in order to recite an after-blessing after drinking a beverage, one must drink at least a Revi’it (approximately 81 cc or 2.8 fluid oz) at one continuous time. However, if one drank less than this amount and paused between sips, one does not recite any after-blessing at all.
Regarding the after-blessing on ice cream, if we consider ice cream to be a food item, if one ate a Kezayit of ice cream in approximately four-and-and-a-half minutes, one would recite a “Boreh Nefashot” after-blessing. However, if we consider ice cream a liquid/beverage, one would not be able to recite an after-blessing since one would not be able to consume a Revi’it of the ice cream in one shot.
Indeed, this idea is subject to a great debate among the Acharonim, for some maintain that ice cream is considered to be a food item (at least with regards to dairy ice cream) and this, one would recite a “Boreh Nefashot” after-blessing after eating it. This is indeed the opinion of Hagaon Rabbeinu Ben Zion Abba Shaul zt”l (quoted in Ohr Le’Zion, Volume 2, Chapter 14). On the other hand, Hagaon Harav Aharon Epstein zt”l rules (in his Sefer Kapei Aharon, Chapter 31 and Halacha Le’Moshe, Chapter 242) that ice cream maintains all halachic ramifications of a beverage and since it is nearly impossible to “drink” a Revi’it of ice cream in one shot, one cannot recite an after-blessing after consuming it.
Halachically speaking, Maran Rabbeinu Ovadia Yosef zt”l rules (in his Responsa Yabia Omer, Volume 5, Chapter 18 and in Chazon Ovadia- Berachot, page 146) that one should not recite any after-blessing after eating ice cream out of concern for the opinions that consider it a beverage.
Similarly, one who drinks frozen slush or a slurpee using a straw would not recite the “Boreh Nefashot” after-blessing when finished as the same halachic ramifications that apply to ice cream would apply here as well.