Granville Raymond Rettew was born on April 19, 1903 in West Chester, Pennsylvania, the son of Granville Leon (1872-1934) and Jane Liggett Rettew (1873-1953). Raymond’s father was an attorney and also served as postmaster of West Chester for eight years. As a youth, Rettew was educated locally, and as a teenager, he worked for the post office and on various area farms. In September 1921, he became a day student at Swarthmore Preparatory School from which he graduated the following June. In September 1922, Rettew entered the University of Delaware to study chemical engineering, but in September 1923, he transferred to Swarthmore College where he continued his studies in chemical engineering. As a junior, Rettew changed his focus to straight chemistry, though he left the college in 1926 after neglecting his German studies, a language graduation requirement of Swarthmore. 

Following his departure from Swarthmore and after a few weeks of unsatisfying work in his father’s law office, Rettew accepted a position in Philadelphia as a chemist at the Charles E. Hires Co., which manufactured and distributed Hires Root Beer. Simultaneously, Wilmer J. Divine, Rettew’s father-in-law, who worked in Chester County’s mushroom industry, encouraged him to study the production of mushroom spawn. Eventually, in 1929, this led Rettew to join Joseph W. Strode, an acquaintance, in a mushroom spawn business, Chester County Mushroom Laboratory (CCML). Strode supplied the finances and Rettew served as technical director and administrator. Within three years, the company was the largest mushroom spawn maker in the United States. In 1931, the partners formed a subsidiary, The Premier Mushroom Co., which pioneered frozen mushrooms with Clarence Birdseye and his New Jersey firm, Seabrook Farms. In 1937, another subsidiary, Concord Foods, was founded to can mushrooms. Contacts in England led to the successful production of spawn in that country, and a branch of CCML was established near Worthing, West Sussex in 1934. During these years of corporate development, Rettew wrote a book, Manual of Mushroom Culture, originally issued in 1935 with four editions published by 1948. 

In the early 1940s, Rettew continued his studies of the chemical substances produced by mushroom fungi. In an unpublished memoir from the 1970s, he wrote that “the experience with extracting chemical substance from the fungi plus the techniques used for the production of mushroom spawn made a fine base for the study of Penicillin,” an antibiotic discovered in 1928 by Scottish physician and microbiologist Sir Alexander Fleming (1881-1955). Eventually, Rettew found “a good way to get useful quantities of Penicillin quickly.” Because penicillin was proven to cure the effects of World War II battlefield wounds and other illnesses, in 1943, the federal government stated that its production was a top priority. Rettew’s business, together with Wyeth Laboratories, began to manufacture penicillin commercially, and “the [s]pawn business was literally pushed out the back door.” By the end of June 1943, the first shipment of penicillin was delivered to the government, which controlled its distribution.

Following the war, Rettew continued in the penicillin business. In 1951, recognizing his importance, the West Chester Chamber of Commerce named him Man of the Year, which was celebrated by a banquet attended by 300 people. One year later, Rettew wrote, “We had visitors from all over the world. These visitors continued to come for many years and was one of my most enjoyable duties.” In addition, Rettew traveled to foreign countries, including Brazil, Italy, Belgium, Sweden, and England, on trips connected to the manufacture of penicillin. According to Rettew, for nine years, beginning in 1955, he did consulting on spore germination for the local mushroom industry. In addition, Rettew held several civic leadership roles in the community, including board member of the National Bank of Chester County (1956), President of the West Chester Civic Association (1958), and President of the United Fund of Greater West Chester (1963). 

Having suffered from cancer for some years and in failing health, Raymond Rettew died on June 24, 1973. He is buried in Forks of the Brandywine Presbyterian Cemetery, Glenmoore, Chester County, Pennsylvania. On July 10, 1926, Raymond married Helen Mildred Divine (1903-1986) at Westminster Presbyterian Church in West Chester. They had three children: Jeanne Ann (b. 1927), Robert Scott (1931-2004), and Gregg Laurence (1935-2018).

Raymond’s historic marker (https://www.hmdb.org/m.asp?m=8153), located at the intersection of East Chestnut Street and North Walnut Street in West Chester, reads: “A West Chester chemist, he [G. Raymond Rettew] pioneered the mass production of penicillin, the world’s first antibiotic. In 1943, with Wyeth Laboratories, his lab (a converted auto repair shop here) made and sent more penicillin to the Armed Forces than any other lab in the world, saving countless lives on the battlefields of World War II.”