Company Names, addresses, dates:
  Beck, Henry, Mineral water company, Alexandria VA (circa 1864) ¹
  Pogensee, Christian, Brewery, Alexandria VA (circa 1865-1875) ²
  Pogensee & Beck, Alexandria VA

Notes:
An Alexandria Archeological report ² says that Christian Pogensee teamed with George Steuernagel and opened a restaurant & brewery in Alexandria VA shortly after the civil war ended, and that the brewery was no longer in operation by the mid 1870s.
An article in the Alexandria Gazette from Feb 19, 1864 said that the local bottlers were going to have to raise the price of their mineral water & cider to 50 cents per dozen (14) bottles, and it was signed by "FOGERTY & COLEMAN" and "HENRY BECK". I presume that those were 2 separate bottling companies, and that the "HENRY BECK" is the same "BECK" on the bottle below. I have no idea why it said "14" in parenthesis after the word dozen - was 14 really considered a dozen back then?
Anyway, I never found any city directory entries or newspaper articles that listed both Pogensee & Beck. The style of the bottle indicates it's pre-1880s, so I'm guessing that they were together in the mid to late 1870s.

Bottles:

(enlarge)

This is an aqua 6.8" blob-top bottle marked: front: POGENSEE & BECK / ALEXANDRIA / VA bottle: BOTTLE / NOT SOLD