The sostenuto pedal – free course

The middle pedal on grand pianos is the sostenuto pedal. It is the least known, yet it offers a unique possibility: sustaining only certain notes while the others stay dry.

How it works

You play one or more notes and hold them with your fingers: their dampers are raised.
You press the sostenuto pedal: it "catches" those particular dampers in the raised position.
You release your fingers: those notes keep sounding. All notes played afterwards behave normally (damped on release), unless you also use the sustain pedal.

Key point: press the sostenuto pedal after playing the notes to be held and before releasing them.

M:4/4
L:1/8
Q:1/4=80
%%staves {RH LH}
V:RH clef=treble
V:LH clef=bass
[V:RH] z2 .[EGc]2 .[FAc]2 .[EGc]2 | z2 .[DGB]2 .[CEG]2 .[DFB]2 |]
[V:LH] "^sost."[C,,C,]8- | [C,,C,]8 |]

Here the low octave is caught by the sostenuto pedal; the right-hand chords stay crisply detached, which would be impossible with the sustain pedal.

Uses

Pedal points (held bass) under changing harmonies or detached passages.
20th-century music: Debussy (some editions), Ravel, Messiaen, Barber and Crumb use it or benefit from it.
Combination with the sustain pedal: sostenuto holds the bass, the sustain pedal changes freely above.

Beware: on many upright pianos the middle pedal is not a true sostenuto: it is often a practice mute (a felt strip comes between hammers and strings for very quiet practice) or a sustain pedal limited to the bass. On digital pianos, the behaviour depends on the model.

Tip: train the coordination: left hand plays the octave, a foot presses the sostenuto, and the right foot remains free for the sustain pedal. Some pianists use the left foot for sostenuto so that the right foot can stay on the sustain pedal.