From the OHS PC Database, derived from A Guide to North American Organbuilders by David H. Fox (Organ Historical Society, 1991) —

Johann Georg [John George] Pfeffer. Born April 23, 1823 in Stetten am Hohenzollern, Germany; father of Robert, Anthony, George, and Eugene Pfeffer.

He immigrated to the United States, 1854; in New York City, New York, 1854-c. 1856; in Hamilton, Ontario, Canada until May, 1857; briefly in New York City, New York; in Cleveland, Ohio; in St. Louis, Missouri, by October 1858; acquired Wilhelm Metz shop of St. Louis, Missouri, 1864; established J. G. Pfeffer & Son of St. Louis, Missouri, 1882; retired 1900; sold the business to Kilgen firm, 1909; died April 4, 1910 in St. Louis, Missouri.

Sources:

• Orpha Ochse, The History of the Organ in the United States (Bloomington: Indiana University Press, 1975), 306.
• Organ Handbook 1986 (Richmond, Va.: Organ Historical Society), 19.
• Donald T. Petering, John George Pfeffer, St. Louis Organbuilder, Master Thesis, Concordia College, River Forest, IL, 1979.

See also: Geo. Kilgen & Son, Inc.