סימן נו סעיף ו
אֲפִלּוּ אִם סִיֵּם כָּל הַבְּרָכָה בְּטָעוּת, אֶלָּא שֶׁנִּזְכַּר תּוֹךְ כְּדֵי דִּבּוּר וְתִקֵּן אֲמִירָתוֹ, כְּגוֹן שֶׁלָּקַח כּוֹס מַיִם אוֹ שֵׁכָר קָסָבַר שֶׁהוּא יַיִן וּבֵרַךְ בּוֹרֵא פְּרִי הַגָּפֶן, וְנִזְכַּר מִיָּד שֶׁהוּא מַיִם אוֹ שֵׁכָר וְסִיֵּם שֶׁהַכֹּל נִהְיָה בִּדְבָרוֹ, וְכָךְ הָיְתָה אֲמִירָתוֹ, בּוֹרֵא פְּרִי הַגָּפֶן שֶׁהַכֹּל נִהְיָה בִּדְבָרוֹ, יָצָא.
Even if you completed the entire berachah erroneously, but you became aware [of your mistake] at once and you corrected the recitation; for example, if you took a glass of water or beer, and, thinking that it is wine, you said the berachah, Borei peri hagafen and you discovered immediately that it was water or beer, and you concluded [by saying the words] Shehakol ni'yah bidevaro, you said in fact: Borei peri hagafen—shehakol ni'yah bidevaro—you have fulfilled your obligation.3This leniency applies only in the case of those berachos which are of Rabbinic origin. Not so with Birkas Hamazon, which is mandated by Torah law. Consequently, if after eating bread, you mistakenly begin to say Baruch ata … al ha’eitz ve’al peri ha’eitz, and then discovered your error and continued hazan es ha’olam, you must start from the beginning, with Baruch ata ….
But if you mistakenly said Al hamichyah after eating bread, you need not repeat from the beginning, but may continue with hazan es ha’olam, since michyah and mazon, sustenance and nourishment, are synonymous. (Mishnah Berurah 209: 6)
תנא דבי אליהו כל השונה הלכות בכל יום מובטח לו שהוא בן העולם הבא שנאמר הליכות עולם לו אל תקרי הליכות אלא הלכות (נדה ע"ג.)