This Trio comes at the end of Brahms' early chamber compositions and in many ways looks back nostalgically to his youth. First of all, the specification for "natural horn" (without valves) as opposed to the modern and more familiar valved horn was for Brahms a keen reminder of his childhood. His father had been a professional natural horn player and had instructed the young Brahms on that instrument. Second, Brahms quotes the folk song "Dort in den Weiden steht ein Haus" (There in the Willows Stands a House) in the Adagio movement, one of his childhood favorites, learned from his mother. There is some evidence that this entire, deeply emotional movement was an elegy in her memory. And last, the entire mood and tone of the piece, aided in no small part by the scoring, is evocative of nature and hunting, two of the most important themes of the Romantic movement to which Brahms was closely allied, via Schumann, in his youth. Also, mainly because of the scoring and its allusions to "occasional" rather than "serious" music, this Trio stands somewhat apart from Brahms' other chamber works. It is unique in his output, yet remains a deeply personal statement.
Instead of the usual sonata movement, Brahms opens the Trio with an expanded ternary-form Andante movement (ABABA) that alternates a longing and nostalgic melody with a faster, yearning passage. Again Brahms avoids the usual form and puts the principal section of the Scherzo into an abbreviated sonata form. It is a rousing hunting song, full of energy and good spirits. The central Trio is a Ländler, an Austrian folk dance, which adds to the rustic flavor of the entire movement. Introspective and deeply personal, the third movement Adagio is in a simple ternary (ABA), yet is complicated by Brahms' use of a fugal exposition to present the principal material. It is in the emotionally charged reprise that Brahms quotes the aforementioned folk song, to great rhetorical effect, one of Brahms' most intense compositions. As if to compensate for the Adagio, Brahms concludes the Trio with as light and rollicking an Allegro as he was capable of writing. Again the horn's hunting qualities are featured, and the Trio ends in a virtuosic tour de force for all three instruments.