I contacted Ron Fowler at hutchbook, and here is what he said:
"S. Schirmer is listed on page 322 of Mike Burggraaf and Tom Southard's book "The Antique Bottles of Iowa 1846-1915," Volume II. They list Schirmer has being in business 1884-1911. The accompanying text mentions "Sebastian Schirmer had previously been in the soda water business in the 1870s at Bellevue and around 1883 at Grundy Center. He came to Emmetsburg in 1884 and established his bottling works."
We have these two Hutchinsons catalogued for this bottling plant:
IA 149 - Emmetsburg, Palo Alton County, Iowa: S. SCHIRMER / EMMETSBURG / IA. = 2 leaf mold, aqua, 6.500" x 2.375" with round (oval) plate mould, W F & S MIL. 204 on back heel, blank base, round base, Rare (less than 10 known).
IA 150 - Emmetsburg, Palo Alton County, Iowa: S. SCHIRMER / EMMETSBURG / IA. = 2 leaf mold, clear, 6.750" x 2.500" with round (oval) plate mould, blank back, blank base, round base, Rare (less than 10 known).
The identical engraved plate mould was used for IA 149 and IA 150.
A close examination of your bottle suggests it is a third variant. The spacing on the letters in the front plate mould are different from IA 149 and 150, and your bottle has an "S" on the base. We are cataloguing your bottle as IA 151. That said, in order to complete the catalog entry, would you please respond with the bottle's height and diameter dimensions."
Pretty cool! I also cleaned it up this weekend, so I'll post some pictures this evening after work. I used a combination of oxalic acid and the brass trick, and it took out most of the blue stains.
This is a shot in the dark, but do you still own this bottle? This is a bottle from my 3rd great-grandfather's company. Sebastian Schirmer was the son of a beer brewer, and his soon-to-be wife didn't want anything to do with a beer brewer, so starting a soda pop bottling company was the compromise. I'd to purchase it as a keepsake.