That's perhaps not the major distinction for a medieval tavern. More important is whether you're talking beer, or "small beer".
"Small beer" is low-alcohol beer, sometimes served unfiltered (and thus kind of porridgey). The point here was that the water supplies were none-too-good, but you don't want to drink full beer all day, as you'd be drunk all day. Small beer is brewed long enough for the alcohol to kill off microbes, but not enough that you're stumbling around soused all the time.
And thus the name Drinkwater. Because insisting on drinking water just stood out that much. In the London cholera epidemic the folks working at a brewery in the area around the tainted well were unaffected, because if you were working at a brewery then why drink
water?
St. Guinness the Stout of Brewer's Gate? I think that I've heard of him!
And his archnemesis Sir Scrumpy Jackpalsy!
I'd like to mention cider as a drink that would probably be available in taverns, particularly in temperate countries where apples are abundant. Cider was traditionally drunk pretty much throughought Western and Southwestern Europe, and since it's fermented for anywhere between 3 months and 3 years, it would be available all year.
The high acid content made it turn vinegary rather than go green. And a scrumpy or rough cider used forced fermentation - traditionally a leg of mutton was sealed into the keg with the cider, when the keg was opened, there'd be naught left but bone.
The Auld Grump
*EDIT* Mutton, or... other meat....
Dead Dog Cider
In eighteen hundred and forty-nine, in a little cider mill,
A poor old dog lay down to rest, for he was feeling ill;
He chose a most precarious perch, above the apple press,
And in his sleep he tumbled in and perished in distress.
This caused his master for to grieve, likewise his mistress too,
And so their sorrows to relieve, they sampled of the brew;
"Gadzooks," cried Farmer Afwater, "the likes I ne'er did sup;
Let's summon all the neighbors in, and bid them take a cup."
Now, here's to Dead Dog Cider, the best there is by far;
Here's to Dead Dog Cider, no moaning at the bar;
You can search this wide world over, find many a beer or ale;
But, when you've tried Dead Dog Cider – your search will be curtailed!
Now everyone that drank that night got drunk as drunk could be,
And wondered how the scrumpy had acquired such potency;
The farmer kept his council, as he took another drop,
When all at once that poor old dog came floating to the top.
A silence fell around the room, and everyone did frown,
For they recognized old Bendigo, though he was upside down;
The parson lost his color and collapsed upon the floor,
And the squire split his britches in the rush to reach the door.
Now, here's to Dead Dog Cider, the best there is by far;
Here's to Dead Dog Cider, no moaning at the bar;
You can search this wide world over, find many a beer or ale;
But, when you've tried Dead Dog Cider – your search will be curtailed!
"Oh, halt!" cried Farmer Afwater, "For in his life I vow,
He never bit man nor beast, nor will he bite ye now;
And this shall be his epitaph, 'Here lies old faithful Ben
Who perished in the cider vat, only to rise again.'"
So if you're down in Devon, and you stops off at a bar,
Just call for Dead Dog Cider, it's the best there is by far;
Refuse all imitations; you'll sleep just like a log,
You can always recognize it by – the hair of the dog.
Now, here's to Dead Dog Cider, the best there is by far;
Here's to Dead Dog Cider, no moaning at the bar;
You can search this wide world over, find many a beer or ale;
But, when you've tried Dead Dog Cider – your search will be curtailed!
Yes, when you've tried Dead Dog Cider – your search will be cur-tailed!
Written by Trevor Crozier © 1977
After the singing of Norman & Betty MacDonald,
Bristol-Birmingham, England, as learned from Anne Dodson