Commentary for Berakhot 71:12
ומי גרע ממלח וזמית דתנן על המלח ועל הזמית אומר שהכל נהיה בדברו אצטריך סד"א מלח וזמית עביד אינש דשדי לפומיה אבל קמחא דשערי הואיל וקשה לקוקיאני לא לבריך עליה כלל קמ"ל כיון דאית ליה הנאה מיניה בעי ברוכי:
Is, then, [barley-flour] of less value than salt and brine? For there is a teaching: Over salt and brine one says "...By Whose word all things exist." It was necessary ; for otherwise it might have entered thy mind to item, the rest being accessory; consequently it is established that there is a circumstance where oil requires a benediction. say that salt or brine a man is accustomed to convey to his mouth [with his food, and therefore a benediction is required], but since barley-flour is injurious by creating tape-worms no benediction should be uttered at all ; therefore he teaches us that since there is some enjoyment therefrom, it is necessary to pronounce a benediction.