The Lemp Brewery, a brick complex covering almost 14 acres with more than 20 buildings dating from 1874 to 1912, grew from the work of German-born Adam Lemp, who introduced lager beer in the United States. After learning brewing from his father in Germany, Lemp opened a grocery in St. Louis in 1838 and brewed lager beer in the back. At a time when Americans were accustomed to ale, which fermented in only a few days, lager beer, preferred by German immigrants, required lengthy aging in a cool environment. Lemp recognized that the naturally cool cave system beneath St. Louis could be used for this process, and rising demand led him to abandon the grocery and focus on brewing, hauling beer south to Cherokee Caves at Broadway and Cherokee for aging. Soon after William Lemp took over management from his father in 1864, he began construction of the first phase of the brewery complex. By 1870, Lemp was the largest brewery in St. Louis and, until Prohibition, controlled the lion's share of the city's brewery market.