William "Bill" Louis Wissmiller, age 89 of Grinnell, died on January 19, 2021 at the Mayflower Community Health Care Center in Grinnell. William was born in Paxton, Illinois, on December 11, 1931, to Gertrude and Louis Wissmiller of Gibson City, IL. He was graduated from Drummer Township High School in Gibson City, IL, and served in the U. S. Army during the Korean War from February 1952 to February 1954. On June 22, 1957, he married Theresa Jean Stine of Paxton, IL. He was graduated from the University of Illinois in 1960 with a BS degree in agronomy and continued in graduate school until he was recruited by Cargill. Bill was employed by Cargill, Inc., as a research scientist from 1960 until 1997. His employment was in Rochelle, IL, and Grinnell, IA, ending in a three-year period in Harare, Zimbabwe. Bill is survived by his wife, Jean of Grinnell; two children: Ann Cortelyou of Denver, IA, and Paul Wissmiller of Minneapolis, MN; two grandchildren: Kira and Kendall Cortelyou of Denver, IA; and two sisters and one brother in Illinois. He was preceded in death by his parents; and four brothers and a sister. Cremation has taken place at the Smith Funeral Home in Grinnell and no visitation is planned. A memorial service will be held by the family at a later time. Memorial contributions in Bill's name may be made to the Drake Community Library or to UnityPoint Grinnell Regional Medical Center and mailed in care of the Smith Funeral Home, PO Box 368, Grinnell, IA 50112. Memories and condolences may be provided to Bill's family online at www.smithfh.com.