- One may not recite a blessing on a food that is not in his presence and he is not certain that it will be brought before him. If the person did recite the blessing, then even if the food was brought before him, his blessing is invalid, and he must say the formula “Blessed is the Name of His glorious kingdom for all eternity” because of his first blessing which was said in vain, and the recite the blessing anew (Shulchan Aruch and Kaf HaChaim 206).
2. However, if the food was merely closed in a cabinet and he had the ability to retrieve the food himself [that is, it was in his own control and he was not dependant on the will of others], and he took the food out of the cabinet after reciting the blessing, he does not have to repeat the blessing. Some authorities rule that even if it was not in his control but he was certain at the time of the blessing that the food would be given to him (such as when the food is in an adjacent room), he does not have to repeat his blessing. Before the fact, however, it is certainly not correct to do so (Mishnah Berurah ad loc.).