Standing aboard his good ship Guppy, Cap’n Crunch boasted in his television debut that his cereal was “so crisp, it never uncrunches — not even in milk!”

Kids watching at home in the 1960s didn’t know it, but it took a lot of labwork to perfect that crunch. Elwood Caldwell and his team at Quaker Oats had spent months developing the cereal at the company’s Illinois research facility, after executives had brought them images of the mustachioed cartoon seaman and friends.

“We had no idea how to achieve a bowl life ... of two minutes,” Caldwell told Brandweek magazine in the 1990s, referring to the time before cereal becomes soggy. “We were just told that we had to do it.”

Caldwell would go on to become of the nation’s premier experts in cereal science, as director of research and development for Quaker, department head at the University of Minnesota and scientific director for the Eagan-based American Association of Cereal Chemists (AACC).

Caldwell, of Roseville, died on May 22 at age 95.

He packed much of his knowledge, and that of others, into an exhaustive reference book detailing the technology behind how breakfast cereal is made. But he also became a go-to resource for food scientists across the country, who took his courses and called on him with highly technical questions.

“He became very important in that field and for very good reasons,” said Jon Faubion, a Kansas State University professor who worked with Caldwell in Minnesota.

The Manitoba native got his start working as a cereal chemist in Canadian flour mills during World War II, after someone at the war office suggested a local mill needed help, said his son Keith Caldwell, of Eagan.

“They told him to go and then he ran with it and never looked back,” Keith Caldwell said.

He later took a job with Quaker and moved to Barrington, Ill., where the company had its research and development facility. He would often return home from work carrying unmarked white boxes of test cereal.

“We’d test them out and give him a thumbs up or a thumbs down,” said his son, John Caldwell. “To this day he would never tell us if we made or broke any of the major cereals that he helped produce.”

Elwood insisted the family eat oatmeal at breakfast before delving into the sugary stuff, though.

At Quaker, Caldwell helped create Instant Oatmeal and Life Cereal, and discovered new methods of keeping cereal products fresh. He also led the team working on Cap’n Crunch, a cereal unusual for its origins as a marketing idea based on the fictional character.

“We had a description of what it would look like and taste like long before an ounce of it was made,” Caldwell told Brandweek.

Another Quaker employee has been posthumously credited with inventing the cereal. Caldwell told his son John that the man worked for him.

“No single individual develops a food product,” Faubion said. “It’s a team, always.”

Caldwell moved to Minnesota in the early 1970s to become the first leader of the U’s Department of Food Science and Nutrition, a post he held for 14 years. Gary Reineccius, interim head of the department, said he adeptly managed the tricky task of merging research-focused food science and teaching-focused nutrition programs.

Outside of work, Caldwell played a number of instruments and frequently attended local orchestra concerts.

Besides his son Keith, he is survived by son John, of Atlanta, as well as several grandchildren. He was preceded in death by his first wife Irene and second wife Florence. Services have not yet been announced.