The grape tree that is Malchut, stretches out three branches that represent the three columns and the three Patriarchs that connect us to holiness.
The wine connects us to the holy and help us draw light and joy like a bride rising with love to receive her groom and his light. Then the grapes on the grape tree gets ripped and get filled with the good and old wine that Jacob connected Chassadim to it.
Those who make the meal blessing, Birkat Hamazon, with wine should add water to the wine before they come to the third blessing , ‘רחם יהוה אלהינו על ישראל’, that asks for mercy on Israel and Jerusalem. As we learned, wine represents the Light of Chokmah and judgments in Malchut and without water that is chassadim we can not draw mercy to Malchut.
This was the message that the wine Stewart delivered to Joseph through his dream. See DZ 2774 #84.
Daily Zohar # 2776 – Balak – Why we put water in the wine