Just as the Beracha of "Ha’mosi" recited over bread covers all foods eaten during the meal, similarly, the Beracha of "Ha’gefen" recited over wine covers all beverages drunk subsequently. Therefore, if one drinks wine and then water, he does not recite "She’hakol" over the water, as the water was covered by the Beracha recited over the wine.
Furthermore, the Beracha of "Ha’gefen" recited over wine immediately before a meal covers the wine that one drinks during the meal. Normally, one who drinks wine during a meal must recite "Ha’gefen" before drinking, because "Ha’mosi" does not cover wine. Although it covers other foods and beverages, wine has a special status and is not covered by "Ha’mosi." However, if one drank wine immediately before a meal, such as on Shabbat, when Kiddush is recited over wine before the meal, he does not then have to recite a Beracha over wine he drinks during the meal. As long as he frequently drinks wine during a meal, the Beracha he recited over wine at Kiddush covers the wine he subsequently drinks during the meal.
There is a debate among the Halachic authorities as to whether the Beracha recited over grape juice also covers other beverages. Rav Yosef Shalom Elyashiv (Jerusalem, 1910-2012), as cited in the work Ve’zot Ha’beracha, maintained that the Beracha of "Ha’gefen" recited over grape juice does not cover other beverages, because grape juice does not have the same special stature as wine. Hacham Ovadia Yosef, however, vehemently disagreed with this ruling, and maintained that the Beracha of "Ha’gefen" always covers other beverages, regardless of whether it is recited over wine or grape juice. He contends that the stature of grape juice is equal to that of wine, as evidenced by the fact that it can be used for Kiddush and Habdala. As such, the Beracha recited over grape juice is no different from the Beracha recited over wine, and in both cases, it covers other beverages.
Summary: One who drinks wine during a meal must recite "Ha’gefen" before drinking, because the Beracha of "Ha’mosi" does not cover wine. On Shabbat, however, when Kiddush is recited just before the meal, the Beracha recited over wine at Kiddush covers the wine drunk during the meal. When one drinks wine or grape juice and then drinks other beverages, he does not have to recite a Beracha over the other beverages, because the Beracha of "Ha’gefen" over the wine covers the other beverages.
