The power of one to change the course of events is much on minds these days, and what works in society also can be a huge factor in music. You could hear it happen in real time Saturday night as four wind players had their say, and pianist Jonathan Biss, in the gust of a single phrase, changed the character and direction of the piece.

The gathering had a dual purpose. It was the second concert this season produced by the Philadelphia branch of Music for Food, a national initiative that raises money for food-insecurity organizations through classical concerts. The first local one in October raised enough to pay for 5,000 meals.

This one, at the First Unitarian Church near 22nd and Chestnut Streets, will allow for another 5,000 meals to be served by the Sunday Breakfast Rescue Mission, says organizer (and Curtis Institute of Music student) Cassie Pilgrim. Biss is artistic director of Food for Music Philadelphia, and a third concert is planned for this spring.

Good intentions, for sure, and the goal, presumably, is to keep expenses low through the use of modest venues. But churches aren't always the best places to hear chamber music, and the acoustic of First Unitarian was muddy, especially in the Brahms Quartet in A Major for Piano and Strings, Op. 26. It's not the composer's most memorable piece of chamber music, and the mix of Curtis Institute faculty (Biss and violist Kim Kashkashian) and students (violinist Ania Filochoeska and cellist Joshua Halpern) wasn't able to prove otherwise.

But the sequence at the end of the piece – the grand summing up, a quiet grace, and a flourish  – was emphatic and passionate.

The Beethoven Quintet for Piano and Winds had the virtue of abundant charm, an aspect the performers caught perfectly. If the wind players – Pilgrim on oboe, fellow student clarinetist Tania Villasuso, plus bassoonist Daniel Matsukawa and hornist Jennifer Montone of the school's faculty – were tempted to wallow in the beauty of their sound, Biss cured them of the notion. In this piece, he heard Beethoven's most fluid and liberating piano writing, and the philosophy played out in this interpretation in the most flattering of ways. Matsukawa was an especially fine presence here, blending with care.

Biss found details many before him have overlooked in this piece. He's so beautifully alert to finding the essence of a work's true temperament that he never lets your attention ebb. He heard the last movement as a hunt, and for it, his touch became light and his pace fleet. He was as a piece of lace, supporting the structure and setting it in motion.

The next Music for Food Philadelphia concert is scheduled for March 15 at 7:00 p.m. at
Saint Mark's Episcopal Church, 1625 Locust St. Donations of $20+, $10+ for students/seniors, collected at the door. The concert benefits Saint Mark's Church Food Cupboard. 678-447-1000, www.musicforfood.net.