Ok, maybe a little ridiculous, but if this proofs easy to code, i think it is a great scroll.
Scrolls shouldn't be to powerfully game changing but rather fun RP potential in my opinion.
So what the Gambrinus(Jan Primus, Hertog/Duke Jan, historical/mythical figure) scroll does is auto refill all beer kegs in a certain area over a certain period of time, very handy for advies, and powerful to attract advies.
Additionally it could also slightly improve morale and or/loyalty in all regions in this area, reflecting a vast if not endless supply of beer in the area.
Also if a Tournament is held in this area, people can give out free rounds of beer.
Beer has always been an important element in many rps, especially tournaments from what i remember.
A scroll like this could offer great RP potential.
Since my idea for weather scrolls was bounced, i figured i should opt this one.