We learn that once the meal is considered to have been concluded, one is prohibited from eating any longer until he recites birchas hamazon. Rashi makes it clear that he cannot eat even if he should choose to make a new bracha. What is the essence of this prohibition?
The Gemara concludes that we recite the bracha of ‘borei shemen areiv’ on the fragrant balsam oil. How can we use the term ‘borei’ on an item that was produced by man (through extraction), just as we cannot apply the term ‘borei’ (borei pri hazayis)with reference to olive-oil since it is man-made (see Rashi 35b D”H zayis ikri)?