There is a common misconception regarding the recitation of the Beracha of "Shehakol" when one is uncertain which Beracha a food requires. Many people mistakenly think that anytime they eat a food over which they do not know which Beracha to recite, they can simply recite "Shehakol." This is incorrect. It is true that after the fact, a person who recited "Shehakol" over any food may then eat the food without reciting another Beracha, even if the food actually requires a different Beracha. This does not mean, however, that anytime a person is uncertain about the Beracha he should recite "Shehakol." As the Gemara in Masechet Berachot says, "Yelech Esel Hacham" one must consult with a Rabbi for guidance regarding the proper Beracha. If a person is unsure which Beracha to recite, he should simply pick up the telephone and call a Rabbi to find out the Halacha, rather than relying on the Beracha of "Shehakol."
The use of "Shehakol" as a last resort in situations of doubt applies only to foods regarding which the Halachic authorities are uncertain, or if there is a debate among the Halachic scholars which has not been definitively resolved. In such circumstances, we recite the Beracha of "Shehakol" in order to satisfy all opinions. But if a definitive Halachic ruling exists, and a person is unaware of which Beracha to recite due to ignorance, he has a Halachic obligation to find out the proper Beracha, and he should not rely on the Beracha of "Shehakol."
This misconception is, unfortunately, quite widespread. In fact, I recall once praying in a synagogue where a man was called to the Torah and could not remember which Beracha to recite over the Torah reading and so he recited the Beracha of "Shehakol"! This individual thought that "Shehakol" was the "cure all" Beracha, for all situations requiring any Beracha. This is obviously incorrect. Even after the fact, "Shehakol" is effective in fulfilling ones obligation only with regard to food, and, according to some opinions, with regard to smelling fragrances, as well.
Summary: If a person is uncertain which Beracha should be recited over a certain food he wishes to eat, he must consult with a Rabbi to determine the proper Beracha; he should not recite "Shehakol." The Beracha of "Shehakol" is effective only after the fact, if one mistakenly recited it over a food requiring a different Beracha. We recite "Shehakol" in situations of uncertainty only if the Halachic authorities themselves cannot definitively determine the proper Beracha.
