Cyril P. Callister Cyril P. Callister Cyril Percy Callister (16 February 1893 – 5 October 1949) was an Australian chemist and food technologist who developed the Vegemite yeast spread. The son of a teacher and postmaster, and one of seven children, he attended the Ballarat School of Mines and later won a scholarship to the University of Melbourne. He gained a Bachelor of Science degree in 1914 and a Master of Science degree in 1917. In early 1915, Callister was employed by food manufacturer Lewis & Whitty, but later that year he enlisted in the Australian Imperial Force. After 53 days, however, he
Cyril P. Callister was withdrawn from active service on the order of the Minister for Defence and assigned to the Munitions Branch, making explosives in Britain. Following the end of World War I, he married Scottish girl Katherine Hope Mundell and returned to Australia and resumed employment with Lewis & Whitty in 1919. In the early 1920s, Callister was employed by Fred Walker and given the task of developing a yeast extract, as imports from the United Kingdom of Marmite had been disrupted in the aftermath of World War I. He experimented on spent brewer's yeast and independently developed what came to be