In 1861, at age 20, Koch began working as foreman of the tinshop for the hardware firm John Pritzlaff & Company.
ɪn wˈʌn θˈaʊzənd ˈeɪthˈʌndɹɪd sˈɪksti wˈʌn, æɾ ˈeɪdʒ twˈɛnti, kˈɑːk bɪɡˈæn wˈɜːkɪŋ æz fˈɔːɹmən ʌvðə tˈɪnʃɑːp fɚðə hˈɑːɹdwɛɹ fˈɜːm dʒˈɑːn pɹˈɪtslæf ænd kˈʌmpəni.