Company Names, addresses, dates¹:
(Address-1)
  George Kerwein, 124 N NW (1873-1884)
  Kernwein & Son, 124 N NW (1885-1887)
  Moritz G. Kernwein, 124 N NW (1888-1890, 1894-1900)
  Anton Danhakl, 124 N NW (1904-1910)
(Address-2)
  Ernst Loeffler, NY ave btw 1st & 2nd West (1862-1864)
  Hugle, Abner & Beyer, NY near 1st (1865-1866))
  Charles G. Mueden, NY Ave btw 1st & 2nd West (1867)
  George Kerwein, 115 NY Ave NW (1877)
  George Kerwein & Son, 115 NY Ave NW (1884)
  Moritz Kerwein, 115 NY Ave NW (1891-1894)

Notes:
George Kernwein (c.1824-1887)² was born in Germany³.
The 1867 D.C. City directory says he was the foreman at the brewery on NY Aveneue between 1st and 2nd Streets West. In later years, he's listed as owning a brewery at 124 N Street NW. Just when he took over this brewery is not clear. The City directories don't list him as a brewer there until 1873, but there is a document that says he was a brewer there in October 1871⁴. The address 124 N Street NW was also listed as his home.
Kernwein brewed Lager and Weiss beer¹.

Moritz G Kernwein (1857-1902)⁵ was George's son. He took over the brewery business, first as a partner and later as the sole owner.
I guess his father's name was well known, because even though the city directories referred to the brewery under Mortitz's name from 1888-1900, one of the bottles below refers to the brewery as "GEORGE KERNWEIN'S SON".

The address of Kernwein's brewery in the DC city directories bounces around between "124 N Street NW" and "115 NY Ave NW". These addresses are two different sides of the same city block, which is depicted below in a snippet from an 1883-84 map called "Birds-eye view of Washington City" published by A. Sachse & Co, Baltimore MD. The slanted street in front is NY Avenue, and the street 1 block behind it is N street. I'm guessing the large building in the back of that city block is 124 N Street, and the smaller (red) building in the front is 115 NY Avenue.


The city directory from 1887 lists "George Kernwein" at 124 N Street and "George Kernwein & Son" at 115 NY Avenue, so I wonder if they were planning to expand into both buildings, but when George passed away his son Moritz went back to just one building.

No other brewers were listed at 115 NY Avenue after Moritz Kernwein left it, but Anton Danhakl took over the brewery at 124 N Street after Mortitz passed away.

George Kernwein Bottles:

book # 61 (in the Stoneware section) This is a 7.5" tall stoneware blob-top bottle with a name impressed in the shoulder: imprinted on shoulder: GEORGE KERNWEIN 74

book # 62 (in the Stoneware section) This is an 8.7" tall stoneware blob-top bottle with a name painted in black letters on the front. It says: black lettering: GEORGE KERNWEIN'S SON / TRADE (bust of George Washington) MARK / REGISTERED / WEISS BEER / WASHINGTON, D.C The ceramic stopper has faint lettering that says: GEO. KERNWEIN'S SON / WASHINTON / D.C.