Slot, a native of Mainz, emigrated 1850 to the USA. At first he worked as an accountant for August Krug, the owner of the pitcher Brewery in Milwaukee. In 1856 he was promoted to the management of the Krug Brewery. After the death of pitcher he married in 1858 his widow and changed the name of the brewery, which he took over in Joseph slot Brewing Company. His success grew, as he after the Great Chicago Fire of 1871 sent hundreds of beer kegs as a donation to Chicago. Many of the local breweries did not open again after the great fire and so took over the slot that market shares. The beer of Joseph slot Brewing Company was made popular with one of the most famous American advertising slogans: " The beer did made Milwaukee famous".
Slot died in 1875 in a shipwreck off the coast of England, just before he was able to visit his German homeland. His body was never recovered, but standing at the cemetery Forest Home Cemetery in the southern part of Milwaukee a cenotaph reminiscent of slot.