A person who partook of a Ke'zayit of grain products is required by Halacha to recite the Beracha of "Al Ha'miheya." If a person in such a case mistakenly recited Birkat Ha'mazon instead of "Al Ha'miheya," has he fulfilled his obligation through the recitation of Birkat Ha'mazon, or must he recite "Al Ha'miheya"?
While all Halachic authorities agree that Birkat Ha'mazon indeed covers grain products, they debate the precise parameters of this Halacha. The Shulhan Aruch (Orah Haim 208:17), based upon the position of Talmide Rabbenu Yona (the students of Rabbenu Yona of Gerona, Spain, 1180-1263), restricts this rule to grain products that have been baked, such as cake, cookies and the like. Only when one ate these kinds of foods does he fulfill his obligation even if he mistakenly recited Birkat Ha'mazon instead of "Al Ha'miheya." If, however, one partook of boiled grain foods, such as pasta, or fried grain foods, such as donuts, then he cannot fulfill his obligation through the recitation of Birkat Ha'mazon. Thus, if one mistakenly recited Birkat Ha'mazon after partaking of such foods, then, according to this view, he must recite "Al Ha'miheya."
Many other authorities, however, dispute this ruling and maintain that in all cases where one is required to recite "Al Ha'miheya," if he mistakenly recited Birkat Ha'mazon he has nevertheless fulfilled his obligation. These authorities include the Ritva (Rabbi Yom Yov of Seville, 1250-1330), the Elya Rabba (Rabbi Eliyahu Shapira of Prague, 1660-1712), the Hida (Rabbi Haim Yosef David Azulai, 1724-1806), the Kaf Ha'haim (Rabbi Yaakov Haim Sofer, 1870-1939), and the Mishna Berura (Rabbi Yisrael Meir Kagan, 1839-1933). This is, indeed, the ruling of Hacham Ovadia Yosef, in his work Hazon Ovadia (Laws of Tu Be'shvat, p. 183). Even though the Shulhan Aruch maintains that Birkat Ha'mazon does not cover boiled or fried products, Hacham Ovadia applies to this case the famous rule of "Safek Berachot Le'hakel" that one does not recite a Beracha when there is some uncertainty as to whether it is warranted. Since the Halachic authorities debate the question of whether one must recite "Al Ha'miheya" if he mistakenly recited Birkat Ha'mazon after eating boiled or fried grain products, it is preferable not to recite "Al Ha'miheya" and to rely on the view that he fulfilled his obligation through Birkat Ha'mazon.
Incidentally, it should be noted that Halacha does recognize a distinction between baked grain products and boiled and fried products with respect to a case where one mistakenly recited "Ha'mosi" instead of "Mezonot" before eating. Hacham Ovadia rules that since boiled and fried grain products do not have the appearance of bread at all, they are not covered by the Beracha of "Ha'mosi." Therefore, if one mistakenly recited "Ha'mosi" instead of "Mezonot" over boiled or fried grain products, he must recite a new Beracha of "Mezonot." If this occurred before one partook of other grain products, however, then he has fulfilled his obligation through the recitation of "Ha'mosi" and does not recite a new Beracha.
Summary: If a person mistakenly recited Birkat Ha'mazon instead of "Al Ha'miheya," he has nevertheless fulfilled his obligation and does not need to then recite "Al Ha'miheya." If a person mistakenly recited "Ha'mosi" before eating a "Mezonot" food, then if the product was baked, such as cake, cookies and the like, then he has fulfilled his obligation and does not recite a new Beracha of "Mezonot." If the food was boiled such as pasta or fried such as donuts then he must recite a new Beracha of "Mezonot."
