It's taken from an article about the City Restaurant on Milk Street in Cheapside.
"But about that water?" said somebody, anxiously regarding No. 6.
"Every drop filtered, even the water used for cooking," he said calmly. "I've spent the time looking at the cisterns and the kitchen; but how about the beer up at the top of the house?"
"All right," said sententious No. 4; "right as malt and hops. There's an automatic generator in the cellar, and all the beer is forced up by the pressure of a volume of carbonic acid gas on the vat, the only way to keep the Vienna Beer in condition."
Chorus: "Science is a great invention."
No. 4: "So is beer."
"Food Journal, Volume 3", 1873, page 266.
So they were serving Vienna Lager by top pressure in the 1870's. I guess something as exotic as that would count as craft keg nowadays. Don't I keep telling you that nothing is new?
The City Restaurant seems to have been a pretty famous spot:
"PERETT’S CITY RESTAURANT,
34, Milk Street, Cheapside,
Amongst other questions asked when parties are visiting the great metropolis is Where shall dine? The reply, which is becoming as familiar as household words is, Why at Perrett’s City Restaurant, where the best and cheapest dinner is served in the most unique style in the City of London ; where, also, chops and steaks are served from the silver grill. This room, as well as the dining rooms, are admitted by the public to be the most comfortable and luxuriant in the City; also will be found the most elegant luncheon bar yet fitted up.
Please note the Address!
PERRETT'S CITY RESTAURANT,
34, Milk Street, Cheapside.
Oxford Times - Saturday 04 August 1866, page 1.
That's it for now. Just a random bit of stuff I thought I'd share.