On January 29, at Boston’s Old South Church, the Musicians of the Old Post Road presented a concert of “Hidden Treasures from the German Baroque.” While not all these treasures sparkled equally, they did offer a look into the lesser-known, as well as a listen into the marvelous music-making of this ensemble.

The works that the group chose illustrate the fascinating transition from the multifaceted complexity of the late Baroque to the refined symmetry of the early Classical, a phenomenon that was particularly noticeable in the music of German composers of the time. This music also seems particularly well-suited to the performing style of the Musicians of the Old Post Road: their musicianship is delicate, almost refined, but not so fragile as to break from the currents of vibrancy that they brought to nearly every piece. Nowhere was this more apparent and appropriate than in the first piece on the program, the Quartet in C-major for traverso (Baroque flute), viola, cello, and continuo by Johann Gottlieb Janitsch. This work, a stylistic missing link of sorts between Baroque and Rococo, encloses richly layered textures within an evenly balanced structure, a compositional aesthetic to which the ensemble brought florid energy with galant restraint. Other pieces on the program tended more toward the Baroque side of the spectrum, allowing the performers to engage in expressively ornamented playing. The splendid Sonata in D Major by Johann Friedrich Fasch demonstrated just how sensitively the core of the ensemble—cellist Daniel Ryan, flautist Suzanne Stumpf, violinist/violist Sarah Darling, and harpsichordist Michael Bahmann—can play together.

One of the main attractions of the concert was that it featured two works whose scoring includes the chalumeau, the single-reed forerunner of the clarinet. The Quartet in F Major for soprano-chalumeau, violin, bassoon, and continuo by Johann Adolf Hasse, a Baroque composer who, like Janitsch, often stepped over into the next period, is a brilliant demonstration of how this unusual-sounding instrument can interact and blend with more common ones, in this case the violin and the bassoon. This is especially well displayed in the faster movements through Hasse’s nimble phrasal ball-tossing, which Darling, chalumeauist Owen Watkins, and bassoonist Marilyn Boenau handled with delightful dexterity. On the other hand, Christoph Graupner’s Trio Sonata in C Major for bass-chalumeau, bassoon, and continuo illustrates the pitfalls of choosing instruments primarily for their color. Though the low registers and the single-versus-double reed textures make for remarkable sonorities, Graupner had difficulty getting past these woodwinds’ inherent gracelessness. In fact, they would have sounded downright clumsy were it not for the skill of Watkins and Boenau, who did their best to make music out of less-than-satisfying material.

In contrast, the Concerto in G Major for traverso, bassoon, cello, and continuo by Johann David Heinichen is a model of deft and exciting antiphonal writing for two instruments with very different sounds. Unlike Graupner, Heinichen knew well how to balance the bassoon’s various registers in roles as both soloist—engaging in delightful call-and-response with the flute—and continuo, a duality that Boenau negotiated with adept musicality.

Fortunately, Graupner’s compositional skills were more than redeemed by the ensemble’s lovely performance of his Trio Sonata in d minor for traverso, viola, and continuo, the most contrapuntally sophisticated work on the program. The affective power of this solidly Baroque aesthetic was particularly brought to bear by the beautiful playing of Darling and Stumpf in the work’s largo, a true high point of the program.

The concert ended with an arrangement of J.S. Bach’s aria “Mein gläubiges Herze, frohlocke” from the Cantata Also hat Gott die Welt geliebt (BWV 68). Though somewhat out of place on the program—Bach is hardly a hidden treasure—it did allow the audience to hear all these performers to play together, providing a satisfying end to an evening of exploration.

Tom Schnauber is a Boston-based composer and is currently serving as chair of the Performance Arts Department at Emmanuel College. He holds a Ph.D. in composition and Theory from the University of Michigan.