Blessing any and all wine found before quaffing is highly recommended for the hit point increase.
Raiding the Wine Cellar will yield a large amount of wine, some of which may be blessed.
Consuming blessed wine when your HP is full will result in a permanent +5 to HP.
Caution! There is currently a bug (?) where if you increase your max HP to the point where the health bar resches the map in the upper right-hand corner of the screen, the bar will suddenly reduced in size by two thirds. It is not yet known whether this means that the hit points themselves are reduced or that the health bar is merely rescaling to fit in the space. Further testing is required.