If a person recited Birkat Ha’mazon with the intention of resuming the meal afterward, must he then recite a new Beracha on the food or beverages he eats or drinks after Birkat Ha’mazon? This question occasionally arises when someone is needed to join a Zimun, and he recites Birkat Ha’mazon with two people with clear intent to continue eating afterward. Must he recite a new Beracha over the food he eats after Birkat Ha’mazon? On the one hand, we might say that since he did not intend to complete his meal, no new Beracha is required, as he may still rely on the Beracha he recited at the beginning of the meal. On the other hand, perhaps the recitation of Birkat Ha’mazon by definition signifies "Siluk"- one’s "withdrawal" from the meal, such that he would have to recite a new Beracha when he resumes eating.
Indeed, Hacham David Yosef writes in his work Halacha Berura (vol. 9, p. 257; listen to audio recording for precise citation) that one must recite a new Beracha upon resuming eating after Birkat Ha’mazon. Hacham David emphasizes that this applies even if one eats and drinks the same foods and beverages that were served at the meal, and even if he had clear, explicit intent before reciting Birkat Ha’mazon that he wishes to resume eating and drinking afterward. Of course, one would then recite a Beracha Aharona after he finishes eating and drinking.
Furthermore, Hacham David writes that this Halacha applies as well in a case of one who recited a Beracha Aharona with the intention of continuing to eat afterward. Thus, if a person, for whatever reason, recited "Boreh Nefashot" after drinking but had in mind to continue drinking after he recites the Beracha, he must recite a new Beracha of "She’hakol" before he resumes drinking. This applies as well to the "Beracha Me’en Shalosh" recited after eating grain products, wine or certain kinds of fruit. In all cases, the recitation of Birkat Ha’mazon or a Beracha Aharona signifies the end of one’s eating, such that a new Beracha is required when he resumes eating or drinking, even if he had planned to continue eating or drinking all along.
Summary: If a person wishes to resume eating or drinking after reciting Birkat Ha’mazon or a Beracha Aharona, he must recite a new Beracha before he resumes eating or drinking, even if he had in mind all throughout that he would continue eating or drinking.
