S.P.L. Sørensen

Søren Peter Lauritz Sørensen was born on January 9, 1868, in Havrebjerg, Zealand. Educated in chemistry at the University of Copenhagen, he was appointed director of the chemical department of the world-renowned Carlsberg Laboratory in 1901.

Investigating the effect of ion concentration on enzymatic reactions during beer brewing and protein synthesis, Sørensen recognized that expressing tiny hydrogen ion concentrations in decimals was cumbersome. In his landmark 1909 paper, he introduced the negative logarithmic notation pH (puissance d'hydrogène), alongside standard buffer solutions. His pH scale became an indispensable universal standard across chemistry, medicine, biology, and environmental science.