Because the website for the Noonday Concerts series lists only the performers, not the details of their programs, you never know exactly what to expect when you turn up for one of these free, 40-minute concerts, sponsored by the Portland Conservatory of Music. That can be a good thing, if you like musical surprises. But without the information, you might also decide to skip a concert that you would have attended if you knew what was being played. When organist Harold Stover last performed on the series, in February, I had hoped he might play some of his own organ works, having heard a few in recitals he gave in New York before he moved to Portland in 1992. As it turned out, he devoted that program to Bach and his contemporaries, in performances so transparent and finely nuanced that I couldn’t really be disappointed in his choices.

But when he played on the series again, on Thursday, it was with a program that included three of his own scores – “Tambourine,” “Blue Prelude” and “Narodil se Kristus Pán (Variations on a Bohemian Carol)” – as well as two pieces from Camille Saint-Saëns’ last organ work, “Seven Improvisations” (Op. 150).

None of the originals Stover played are extroverted showpieces, of the sort organist-composers write to dazzle listeners with their technical prowess, or to test the limits of an organ. These were basically gentle scores, meant to draw you in, and they are filled with subtleties, both in substance and coloration, that hold your attention.

“Tambourine” is built on a dotted rhythm that runs through the entire score, and it evokes the percussion instrument for which the piece is named. But that evocation is slightly odd: Instead of giving this keyboard version of a tambourine a bright, jangly sound, Stover made it the work’s bass line, played on the organ pedals, with variations woven above it in bright flute and reed timbres.

The carol on which “Narodil se Kristus Pán” is based is presented in an unadorned, chordal reading at the start of the work, and you can immediately see the possibilities it offers for variation. Stover offered one briskly rhythmic elaboration on the theme, and another in an appealingly chromatic Baroque style. It was not clear whether these were selections from a larger set of variations, excerpted because the concerts are meant to be short, or whether they represented the full score. Either way, the performance left you thinking that there ought to be more.

“Blue Prelude,” a work Stover also played at the Portland Conservatory’s Back Cove Contemporary Music Festival, last April, is a soft-hued essay that inhabits two worlds at once. Its melodic lines are couched in blue notes – the flatted thirds that give a musical line a bluesy character – as well as figures that allude to early jazz. Yet the organ’s sound – Stover used a subdued, dark timbre, here – puts the music’s bluesiness at a distance. You hear the flatted third, but on the organ, it sounds simply like a touch of chromaticism, such as you might find in a Baroque prelude.

The Saint-Saëns selections that closed the program mirrored Stover’s own works in interesting ways. The Poco Lento movement from the “Improvisations” set is a slow, introspective essay that arises – like Stover’s “Tambourine” – from a repeating bass figure. And the set’s brisk Allegro Giocoso movement has the character of a Renaissance dance, which gives it a link to the period and harmonic language, if not quite the spirit, of the carol on which “Narodil” variations are based.

Allan Kozinn is a former music critic and culture writer for The New York Times who lives in Portland. He can be contacted at:

allankozinn@gmail.com

Twitter: kozinn