Bob Koester, who founded the influential Chicago blues and jazz label Delmark Records and was also the proprietor of an equally influential record store where players and fans mingled as they sought out new and vintage sounds, died on Wednesday at a care center in Evanston, Ill., near his home in Chicago. He was 88.
His wife, Sue Koester, said the cause was complications of a stroke.
Mr. Koester was a pivotal figure in Chicago and beyond, releasing early efforts by Sun Ra, Anthony Braxton, Jimmy Dawkins, Magic Sam and numerous other jazz and blues musicians. He captured the sound of Chicago’s vibrant blues scene of the 1960s on records like “Hoodoo Man Blues,” a much admired album by the singer and harmonica player Junior Wells, featuring the guitarist Buddy Guy, that was recorded in 1965.
Muhal Richard Abrams and other members of the Association for the Advancement of Creative Musicians, an organization formed in Chicago in 1965. The company’s recordings were not, generally, the kind that generated a lot of sales.
“If he felt something was significant, he wasn’t going to think about whether it would sell,” Ms. Koester said by phone. “He wanted people to hear it and experience the significance.”
As Howard Mandel, the jazz critic and author, put it in a phone interview: “He followed his own star. He was not at all interested in trends.”
For decades Mr. Koester’s record store, the Jazz Record Mart, provided enough financial support to allow Delmark to make records that didn’t sell a lot of copies. The store was more than an outlet for Delmark’s artists; it was packed with all sorts of records, many of them from collections Mr. Koester bought or traded for.
Charlie Musselwhite, who was a clerk at the store in the mid-1960s, told The Times in 2009, rattling off the names of some fellow blues musicians. “You never knew what fascinating characters would wander in, so I always felt like I was in the eye of the storm there.”
Mr. Mandel said part of the fun was tapping into Mr. Koestel’s deep reservoir of arcane musical knowledge.
“You’d get into a conversation with him,” he said, “and in 10 minutes he was talking about some obscure wormhole of a serial number on a pressing.”
Ms. Koester said the store held a special place in her husband’s heart — so much so that when he finally closed it in 2016, citing rising rent, he opened another, Bob’s Blues and Jazz Mart, almost immediately.
“He loved going into the studio in the days when he was recording Junior Wells and Jimmy Dawkins,” she said, “but retail was in his blood.”