If someone accidentally made a bracha with an uncovered head, was he yotzi or does he have to say it over?
What about if someone davened Mincha or bentched with an uncovered head by mistake?
Although one should be careful to make all berachos with a head-covering (kippah), if a berachah is recited without covering one’s head the berachah is valid, and is not repeated.
The same applies for all prayers.
Even (some of) those authorities who write that there is no obligation to wear a kippah all the time, rule that one must do so when reciting a berachah (Kol Bo 11; Or Zarua 2:43; Tur, Orach Chaim 8; Rabbeinu Yerucham; Taz 8:3).
One must therefore be careful to cover one’s head when making a berachah (see also Orach Chaim 91:4, and Mishnah Berurah 91:10).
However, there is no question that a berachah recited without a head-covering remains valid, and cannot be repeated.