During the party, Krempels played seven solos. His oldest son Doug sang a bass solo. David joined in on harmonica. Daughter Deborah McAfee - who studied at the Peabody Institute of the Johns Hopkins University - played oboe. Krempels' sister and husband joined the family in song.
In his 90 years of life, perhaps the lesson to be learned from Krempels is that like being a student of music, life too can be hard, but rewarding.
"I have one thing to thank as to why I keep going," Krempels said. "I attribute my still going on to the prayers of Jesus."
He still practices scales and arpeggios. His favorite songs to play are "America the Beautiful" and "Beneath the Cross of Jesus." The hardest part about being a teacher, he said, is transferring this motivation to his students. There are also things that cannot be taught - like the interpretation of notes. Krempels' music comes from the heart. If there's no emotion, he said there's no point in playing.
"You can get to the point where you're technically impressive but in music you never get where you're never, never concerned with interpretation," Krempels said. "If it's good music, there's always something to reach for."
Emotion poured from his fingers as he played "All the Way, My Savior Leads Me." As he struck the chords, he said he was thinking "God, you've really done it, you led me all these years."
This is the song that inspired him to marry his wife, Mary Catherine (Garns) Krempels, in 1944. They met at Eastern Bible Institute, what is now Valley Forge Christian College in Phoenixville, Pa.
Krempels said at the time, he wasn't sure that he wanted to be married because his parents had a rocky relationship.
His parents Sarah and Michael Krempels were German immigrants. He was raised in Pennsylvania and came from a family that was very active in church. Has parents introduced him to religion and music.
By age 16, Krempels was the church pianist and directing his church's orchestra. He had been taking piano lessons since he was 6, studying under the same teacher for 10 years, the late Thomas Morgan.
Bob Krempels was a music student and eventually would go on to become a faculty member at Eastern Bible Institute. His future wife was a nursing student at Eastern who would go on to teach and serve as dean of women.
He fell in love with the woman who became his wife.
He recalled spending time in his room, reading and rereading the hymn for guidance. "I was a kid in school crying out for help," Krempels said. Until eventually, "All the Way, My Savior Leads Me" led him to marriage.
He and his wife spent mornings together singing devotionals - right up until her last day. His wife had Alzheimer's disease. Krempels said the last six months of her life were tough.
"Sometimes she'd be right beside me but be miles away," he said.
Lately, Krempels has been playing for lots of funerals.
He didn't play the piano at his wife's funeral. Mary Krempels died Aug. 4, 2008 - the day after her birthday.
She was 91.
Bob Krempels hired a pianist to play some songs he arranged and some of his wife's favorite hymns - "No Other Plea" and "When I Behold Him."
According to a Herald-Mail obituary, the family arranged for a fellowship meal and open mic after her interment.
"She was more for me than a companion. She was really my soul mate," Krempels said.