What a fantastic little article from The Economist.
Beer, they suggest, may have emerged in an attempt to make wild barley edible by mixing it with water and fruit. The thick beer produced in this way would be just as nutritious as bread, in addition to being slightly alcoholic.
On occasion, wine was also diluted with seawater. According to Pliny the Elder, one of several Roman authorities on wine, this was done “to enliven the wine's smoothness”. But water was not the only additive.
Pepys also refers several times to “sack-posset”, a medicinal brew of sack, sugar, spices, milk and beaten eggs that was traditionally served at weddings in early colonial America.