If a Person Changes His Mind and Decides Not to Eat After Listening to a Bracha

Whenever one hears a Bracha, he must answer "Amen" to the Bracha – especially after one hears a Bracha for the purpose of fulfilling his obligation to recite it, for example, if two people want to drink water, and one recites the Bracha on behalf of them both. The one who listens to the Bracha should answer "Amen." However, if, for whatever reason, he did not answer "Amen," he has nevertheless fulfilled his obligation. As long as they both had in mind that the listener should fulfill his obligation through listening, he fulfills his requirement, even though he did not answer "Amen." Interestingly, the Poskim draw an important distinction between one who answers "Amen" to a Bracha he hears to fulfill his obligation, and one who does not answer "Amen." If one does not answer "Amen," he fulfills his obligation, but he is not considered to have actually recited the text. By contrast, once a person answers "Amen" to a Bracha to which he had listened with the intention of fulfilling his obligation, he is considered to have personally recited the Bracha. He is not only credited with having recited a Bracha, but is regarded as having actually recited the words with his mouth. The practical difference between the two cases, as Chacham Ovadia Yosef explains, relates to the possibility of changing one’s mind after fulfilling his obligation by listening to a Bracha. If one answered "Amen," then he is considered to have actually recited the Bracha, and so he does not have the option of changing his mind and not eating or drinking. If he does not eat or drink after reciting "Amen," then he is in violation of reciting a Bracha in vain, even though he did not actually recite the words of the Bracha with his mouth. But if he did not answer "Amen," then he is not considered to have personally recited the Bracha, and so although he has fulfilled his requirement if he still wishes to eat or drink, he has the option of changing his mind.  

Summary: One should answer "Amen" after listening to a Bracha. If one listens to a Bracha with the intention of fulfilling his obligation to recite that Bracha, then after he answers "Amen" he is considered to have actually recited the Bracha, and therefore he must eat the food or drink the beverage, as otherwise, he will be considered to have recited a Bracha in vain. If, for whatever reason, he did not answer "Amen," he has nevertheless fulfilled his obligation and may eat the food or drink the beverage, but he is not considered to have actually recited the Bracha, and so he has the option to change his mind and not eat or drink.

By Rabbi Eli Mansour