By 1848, Carl Hilmar Guenther (1826-1902), master millwright, had completed his apprenticeship in Germany and immigrated to the U.S.. In search of opportunities and a good grist mill site, he journeyed south from Wisconsin to New Orleans, and then west to Texas. In 1851 he bought land and water rights on Live Oak Creek near Fredericksburg. After six months of construction, his mill was operational, but a flood destroyed the first dam. One month after the floor the mill was working again.
Ox drawn wagons loaded with harvested crops converged on the mill in the mornings, and after the farmers' business was completed the men remained to visit with each other. The mill became a center of social life in the Hill Country community.
Guenther was granted U.S. Citizenship in gillespie County in 1854. He married Dorothea Pape in 1855. They lived in a home near the mill and were eventually the parents of seven children.
In 1859 Guenther chose a site about one mile from the center of San Antonio as a new site for his mill operation. Guenther mills soon became the Pioneer Flour Mills, an enterprise which became a flourishing business in Texas and the Southwest.