Wine

Is it true that one does not recite a blessing on any drinks when also drinking wine?

Shalom! 

Thank you for your question. 

Yes. Both bread and wine can exempt other foods from the need for a blessing before one eats them. Bread and wine are also the only foods that were assigned their own unique blessings; all other foods are grouped together under one of several blessing “categories.” 

Because bread (“the basic staple of life”) and wine (“gladdens the heart of man) are prominent foods our sages decreed that the blessing on bread will cover most foods and the blessing on wine will cover most drinks. (Although, because yogurt and ice cream are a safek whether wine exempts them, one should first recite Shehakol on a toffee.) 

So too, just as the bracha rishona recited before bread and wine exempts other foods and drinks consumed along with them, the bracha achrona recited after bread and wine exempts other foods that were eaten, as well. As such, Birkat Hamazon covers everything eaten during a meal (including wine) and al hagefen covers all drinks that were consumed along with wine (when Birkat Hamazon is not recited).

In order for the blessing over wine to properly exempt other drinks, one must drink some wine and not merely hear the blessing being recited. Ideally one should drink a “Melo lugmov” (cheek full) of wine (40cc). One who did not drink a 'Melo Lugmov' should endeavour to recite a “shehakol” on some other food to exempt other drinks that one wishes to consume. If there is no such foods then one should try to find someone who didn't drink any wine, who can exempt him with the Bracha of Shehakol. if either options are not possible then one can indeed consume other drinks without a blessing even if one did not drink 'Melo Lugmov' of wine. But one who did not drink any wine must recite a blessing on the other drink(s).

There is some dispute of grape juice is considered to be like wine for these purposes, and therefore, one who merely drank grape juice (even more than 'Melo Lugmov' should endeavour to recite a “shehakol” on some other food to exempt other the drinks that one wishes to consume, or find some one to exempt him. In a case that no such options are available, than one can indeed consume other drinks without a blessing even if one did not drink 'Melo lugmov' of wine.

 Berachot 41b; OC 174 with commentaries.