Mozart was in love with the sound of the clarinet. He wasn’t able to fully express on paper his adoration for the instrument until the last few years of his life when he met and befriended Anton Stadler. A close friend of Mozart’s and fellow Freemason, Stadler was one of the great clarinetists of Mozart’s time. He was Mozart’s inspiration for this piece as well as the Clarinet Concerto (K. 622). Both this piece and the concerto were written originally for basset clarinet, an instrument whose design was mostly improvisations by Stadler himself.
In the first movement, the clarinet is not the only soloist; the melody is passed throughout the quintet, highlighting the beauty of each of the stringed instruments. The Larghetto however belongs completely to the clarinet, and the muted strings allow the middle register of the clarinet to shine through. The Menuetto and Trios are very dance-like, and again the clarinet blends into the quartet taking a more ensemble role instead of a solo role. The Allegretto con Variazioni is a bit capricious, as the mood constantly changes. Near the end, an adagio section acts as an interlude to introduce the coda, which gives the piece a sparkling finish.