this item is rather large beer mug that can produce beer on demand!
what do you think as a item for the lab or in the field in adventures?
A very nice item, but remember that items cannot cast rituals, and beer created without a momentary ritual (and vis) is not nourishing.
That it's not nourishing is clear ...
But does it make you drunk (temporarily)?
Salve
Widewitt
It should.
We've always liked the "drunk until sunrise - no hangover" version of these spells and items. Usually we make them with MuAq, though, so you drink water that tastes, looks and works like wine or beer. 
could work,however you must put water into the glass to make the beer,fyi
That's how the most popular verson of this effect works, yes.
well, any liquid, really. Urine works just as well.
the quality of the liquid will determin the quality of the beer.
Nope. The quality of the liquid will determine the lasting effect on the drinkers. The quality of the wine or beer is determined by the caster's finesse.
I'm always a bit careful with items that produce food and drink as it isn't nourishing. My version of such an item would be to use two effects:
- A user activated effect to fetch/summon water from a source (like a lake). Range Arcane with the connection built into the mug/pitcher.
- A "turn this into wine" (or beer) triggered by a full mug/pitcher.
That way you get reasonable nourishing drink.
Yeah, the magic of Ars Magica doesn't work that way. And it never has, to my knowledge.
I could poor crude oil into a cup, and change it into beer with Muto Aquam effect. I could poor crude oil into a cup and make you think it is beer with an Imaginem effect targeting taste, smell and probably touch (leave sight alone, because it's just a thick stout). The first MuAq effect wouldn't cause any immediate problems, and the duration of Sun means that it probably passes out of your system before it reverts. The MuIm effect would make you believe it is safe to drink and then you'd probably get sick.
Well muto magic does have some aspects of that. A weak sickly old man transformed into a wolf becomes a weak sickly old wolf. It isn't a stretch then to say that cloudy impure water would turn into crappy beer. Or that clear mountain spring water gives you a crisp clean brew when transformed.
THANKS!
So, urine is for whiskey then? 
Oh No No No. That would be a different spell. But good clean urine would make the best whiskey. 
On a somewhat related note,what would sugar/sweet water do in the beer glass?
BUMP!!!!!!!!!!!!
Bind a Aquam/Herbam/Animal spirit to the item to power the spell and make it ritual so it becomes true liquid/food, then if the actual item spell is low enough you could make items that make real nourishing things to injest. If the spirit is powerful enough and choosen wisely, it could replenish the might quickly enough to make the item a worth pouch or flask for a traveler.
ist that possible?
With Mystery virtues you can bind spirits into items that then power Ritual spells with their Might. Given that the traveling Redcap could use a flask of infinitely clean water or a pouch that provides endless food, it may not be too impractical to go thru the effort of binding a spirit to make such a item.
"Magically created food only nourishes for as long as the duration lasts, and someone who has eaten it becomes extremely hungry when the duration expires." (pg 77, Creo)
Main sympthomes of hangover are dehydration and hypoglycemia.
I would say wour hangover will get worse if you used muto and a lot worse if you used creo.
Also: Would the spell have to penetrate to get you drunk?
who knows?