As we all know, before drinking beer, coffee or tea one recites the Beracha of "She'hakol." At first glance, however, this issue appears to be subject to a debate among the Rishonim (Medieval Halachic authorities). The Shulhan Aruch (Orah Haim 102:10-11) cites two views concerning a case of one who drinks the liquid in which a fruit or vegetable had been boiled. According to the Rosh (Rabbenu Asher Ben Yehiel, Germany-Spain, 1250-1327), since this liquid contains a strong taste of the actual fruit or vegetable, it is considered akin to the actual fruit or vegetable with respect to Berachot. Hence, in the view of the Rosh, one who drinks this liquid would recite "Bore Peri Ha'etz" if it had been used with a fruit, or "Bore Peri Ha'adama" if it had been used for boiling a vegetable. Other authorities, however, disagreed, and claimed that such liquid is no different from regular fruit juices and thus requires the Beracha of "She'hakol."
Seemingly, then, the issue of which Beracha one recites over beer, coffee and tea the liquid in which one had boiled barley (in the case of beer), coffee beans or tealeaves hinges on this debate. According to the Rosh, it would appear, one who drinks these beverages does not recite "She'hakol," but rather the Beracha that is normally recited on the barley (either "Mezonot" or "Ha'adama"), coffee beans ("Ha'etz") or tealeaves ("Ha'etz").
In truth, the Rosh was himself was asked to clarify his position with respect to beer. As recorded in his published responsa (4:15), the Rosh conceded that beer requires the Beracha of "She'hakol," despite its having been produced by cooking barley. He presented two reasons to explain why the case of beer differs from other beverages produced by boiling a fruit or vegetable. Firstly, the standard processing of barley does not conclude in its grain form; the process normally continues to the stages of grinding and baking. A basic rule of Berachot dictates that when a food is eaten before its final stage of processing, it is "downgraded" with respect to its Beracha. Hence, since beer is produced from barley that has yet to reach its final stage of processing, it requires the general Beracha of "She'hakol," rather than earning the special Beracha of "Mezonot" or "Ha'adama." Regarding fruits and vegetables, by contrast, no further processing is entailed once the fruit or vegetable is picked, and thus one who drinks the liquid in which a fruit or vegetable was boiled recites "Ha'etz" (in the case of a fruit) or "Ha'adama" (in the case of a vegetable).
Secondly, the Rosh writes, when beer manufacturers cook the barley, they do so for the purpose of producing the liquid, and not so that the barley will be cooked. Since this process was done with the particular intent of producing a liquid, it requires the standard Beracha recited over liquids "She'hakol." When, however, a person boils a fruit or vegetable in order to cook the fruit of vegetable, the liquid is considered part of the fruit and vegetable and thus requires the Beracha of "Ha'etz" or "Ha'adama."
This second contention of the Rosh can be easily applied to the cases of coffee and tea, as well. When one cooks coffee beans or tealeaves, his intent is to produce flavored water, and not to produce cooked beans or tealeaves. Accordingly, even the Rosh would concede that one who drinks coffee or tea recites the Beracha of "She'hakol," and this is indeed the ruling of Rabbi Moshe Halevi in his work Birkat Hashem (7:52; listen to audio for precise citation). Interestingly, however, he writes that if one mistakenly recited "Bore Peri Ha'etz" or "Bore Peri Ha'adama" over tea or coffee, he has nevertheless fulfilled his obligation and should not then recite "She'hakol." Regarding beer, however, if one recited any Beracha other than "She'hakol" he must recite "She'hakol" before drinking.
This discussion reflects the complexity and intricacy of the laws of Berachot, and how even seemingly obvious and self-evident Halachot are in fact based upon detailed and complicated analysis and debate.
Summary: One who drinks beer, tea or coffee recites the Beracha of "She'hakol." However, if one mistakenly recited over tea or coffee the Beracha of "Bore Peri Ha'etz" or "Bore Peri Ha'adama," he has nevertheless fulfilled his obligation and is not required to recite "She'hakol."
