Here is an article from the University of Adelaide on Medieval drinking as a part of the daily diet:
Three examples of temperance from the sixteenth century make the exceptions that prove the rule. The Venetian Alvise Cornaro promoted temperance in word and deed. He wrote a book, Discourses in favour of a sober life, in which he advocated a diet of extreme renunciation, confirmed by his own example; he drank only not quite .4 of a liter of wine a day, which is more than half a modern bottle of wine. In The Life of the Duke of Newcastle, written by his wife, the duke received praise for his temperance; she wrote, "In his diet, he is so sparing and temperate, that he never eats nor drinks beyond his set proportion." His set proportion was three glasses of beer and two of wine a day. The final exception to prove the rule was a temperance society founded at Hesse in 1600. Its members agreed to restrict their drinking to seven glasses of wine with each meal.A temperence society even I could consider joining. But what of those who were not living the sober life, but merely one of monastic relinquishment?
In medieval England the normal monastic allowance was one gallon of good ale per day, often supplemented by a second gallon of weak ale."Saint George for Merry England" indeed!