Old Lyme — The December sunset was icy and austere, but beneath it in the First Congregational Church of Old Lyme, there was warmth aplenty.

Inside that acoustic marvel of a hall, Musical Masterworks staged a concert that felt like a full-body warm compress. Masterworks Artistic Director (and resident cellist) Edward Arron told the faithful that he designs each of the five programs to match the time of year, and this one was, by design, "warm and cozy."

The other theme he mentioned was friendship: The set of Dvořák miniatures performed were written to be played by the composer and friends ("it feels like there should be a fire in the fireplace," Arron said) and the Mozart Clarinet Quintet was written for Mozart's good friend Anton Stadler, with Mozart playing viola in the ensemble.

Now in its 23rd season, Masterworks runs strong on friendship, as friends meet and greet at each concert, and in this first cold-weather gathering, the faint scent of mothballs on the tweed jackets spoke of the changing seasons. And an old friend, clarinetist Todd Palmer, who performed in the first Masterworks season, was back for his umpteenth time. Arron joked, "He debuted the Dvořák."

Saturday's concert, which will be repeated at 3 p.m. Sunday, opened with Dvořák's Four Miniatures for Two Violins and Viola, featuring violinists Amy Schwartz Moretti and Aaron Boyd and violist (and Masterworks newcomer) Dimitri Murrath. The string duos and trios that punctuate the chamber programs are always intriguing, with the voicings so plainly expressed and the players standing, like a pop band.

The Dvořák set is miniatures in every way. Each built on a simple songlike idea, they sing plainly and get out. Saturday, playing the first violin, Moretti carried the tunes forward with restraint and heart, in the moving, keening octaves of the Romanze and the austere, halting beauty of the closing Elegie.

Two more lesser-known works followed. Next came "Gumboots" for Clarinet(s) and String Quartet, a 2008 composition written for Palmer and the St. Lawrence String Quartet by David Bruce. Bruce writes that he was inspired to write the two-movement quintet by the South African tradition of gumboots dancing, which grew from the time when slaves were given rubber Wellington boots to work on flooded mines. Prohibited from speaking, they learned to communicate by rattling their shackles and thumping their boots. A folk dance tradition grew from this awful legacy. The death this week of South African liberator Nelson Mandela was "a haunting and poignant coincidence," Arron explained.

"Gumboots" provided the heat amid the warmth. Opening with a slow movement, marked "tender," clarinetist Palmer and violist Murrath often doubled — and diverged — for some sonic tricks, and the very static, yet haunting minimalism gave way as Palmer, playing a bass clarinet to start, cried out in the upper register seldom employed. The dances started early, as Boyd, now in the first violin spot, tapped a rhythm and Murrath slowly churned Glass-like figures to start the engines.

The second movement of five dances was all energy and motion, sometimes in three directions at once. Irregular polyrhythms abounded, as the quintet was at its most African, and Palmer spun jumping jazzy lines, especially in the final Afro-Cuban dance, above the turbulence.

The second half opened with a hidden gem of the repertoire: Gershwin's Lullaby for String Quartet written in 1919 and unperformed as a string quartet until 1967. Throughout, the Masterworks quartet played with mutes, and one of the enduring pleasures of this venue is the acoustic shine this hall gives to muted strings.

This little lullaby swings, not rocks, the baby to sleep, and its gentle Jazz Age syncopation and bluesy lilt are pure Americana, set in this traditional Viennese ensemble. Saturday's performance was so gentle and affectionate — yes, and warm — that it left you yearning for more Gershwin for string ensembles.

Palmer returned for what Arron says is the most requested piece from Masterworks' audience members: the Mozart Quintet for Clarinet and Strings in A Major, K. 581. Written late in Mozart's output, it is sheer perfection, and the Masterworks ensemble did it justice.

The work often sets the first violin, with Moretti back in that chair, and clarinet as respondents, and Moretti and Palmer spoke beautifully. This work is so relaxed, so perfectly meshed in its wealth of melodies and its unobtrusive complexity of voicings, that when it goes well, it's hard to notice why. And Saturday, it went very well.

The middle movements, in particular, were luxurious in their beauty. The larghetto, again with muted strings, let Palmer sing a heartfelt arioso with his clarinet, so vocal and personal, it seemed the wistful voice of the Contessa in "Figaro." In response to Palmer, and in the duet sections, Moretti's muted sound was crystalline, almost fragile. In the following minuet movement, Palmer was at his sweetest emerging from the minor to defy the intensity of the opening pages with lines of pure sweetness, without the saccharine.