When the Portland Piano Trio announced itself, and its ambitious educational program, 240 Strings, with a concert at First Parish Church last October, I was taken with the energy and precision of the group’s performance. The three musicians – violinist Tracey Jasas-Hardel, pianist Anastasia Antonacos, and cellist Benjamin Noyes – each brought an unassailable technique and plenty of imagination to their performances, and their interactions were those of a group that had been playing together for a decade, rather than the fledgling ensemble they were.

The trio celebrated the end of its first season with a free concert at One Longfellow Square on Monday evening. With a program that balanced the familiar and the novel – Mozart’s Piano Quartet in E-flat major (K. 493), for which violist Bryan Brash joined the ensemble, Stephanie Ann Boyd’s recent “Ancestry Variations,” and Mendelssohn’s Trio No. 1 in D minor (Op. 49) – the group built upon the strong impression it made last fall.

The ensemble’s strengths, individually and collectively, were immediately apparent in the Mozart, where Jasus-Hardel’s and Brash’s warm, rounded tone, the sumptuous depth of Noyes’ cello sound, and the crisp sparkle of Antonacos’ piano yielded an impeccably balanced texture and lively, spirited interplay.

There were times when the group’s reading veered toward a level of Romantic heftiness that may have seemed slightly anachronistic in Mozart. But this is the kind of performance that makes it hard to take sides in the music world’s perennial battles over period style.

Yes, Mozart’s sound, in its day, may have been lighter and more fleet, and the ideal, at least in theory, is to recreate the music as the composer conceived it. But as this trio and other like-minded groups regularly remind us, the music’s implications often stretch beyond the limits of the instruments available in Mozart’s day, and while it is inherently questionable to suggest that composers of past eras would have wanted a modern sound if it was available to them, it was hard to argue with the expressiveness and overall effect of this trio’s reading.

In any case, their approach was perfectly suited to the Mendelssohn, which is a model of early Romantic steaminess, offset by the kinds of bittersweet, ear-arresting themes that always enliven Mendelssohn’s work. That said, the players’ focus on those themes was carefully calibrated, and never overstated, and there were moments – one was a chromatic ripple at the very end of the slow movement – that were pure magic.

Boyd, a composer in her mid-20s, built “Ancestry Variations” (2014) on Celtic folk themes, which she has filtered through a conservative modern sensibility, with Impressionistic piano washes and gracefully harmonized string lines. I heard the trio play these variations at the Portland Conservatory’s Back Cove Contemporary Music Festival, in April, and both times it struck me as attractive and inventive, but not especially memorable. Perhaps a third hearing will be the charm.

Just before the Mendelssohn, the trio offered a glimpse of its educational work with 240 Strings, a nonprofit organization that provides music lessons to students who might not otherwise have access to them. So far, the group is teaching nine young players between the ages of 6 and 18, and most of them (from the younger end of the spectrum) were on hand on Monday to give enthusiastic performances of a couple of short ensemble pieces, and revel in an audience’s applause. They clearly enjoyed showing off their budding talents, which is as it should be.

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