Josiah Gibbs revolutionized physical chemistry with his mathematics of thermodynamics and chemical equilibria, but published in an obscure journal few read. Wilhelm Ostward explained catalysis with his idea of an intermediate. Einstein figured out the cause of Brownian motion, and gave sufficient proof of atoms and molecules that all scientists accepted atomic theory. These developments led to the journal Zeitschrift für Physikalische Chemie, which still exists today. Arrhenius's ionic dissociation explained many of water's properties, and led eventually to Søren Sørensen's pH designation of acids and bases. Guest, Vincent Falcone, Head Brewer of City-State Brewing in Washington, DC, discusses pH and beer.Support the show