The Romantic period can also be referred to as the era of the sustain pedal. Almost every piece by a Romantic composer depends at one time or another, and sometimes at all, on the use of the sustain pedal.

The basic reason for this change from the music of the classical period was the gradual increase in the loudness of the piano itself. With the heavily enriched harmonics of the new instruments, closed position chords in the bass, whether broken or whole, no longer sounded tolerable. Therefore composers opened chords, playing their notes successively rather than simultaneously, and used the pedal to sustain what could not be stretched with one hand.

This was actually just a development of an existing device: broken chords had long been used to provide rhythmic interest and sustained effect in keyboard music. What was new was the epiphany that the pedal now allowed spaces that were not only out of reach of a single hand, but also remarkably suited to fleeting piano tones. Beautiful new keyboard textures evolved, whose immense potentialities were continually developed up to Debussy’s time and beyond.

Two basic types of chords evolved to accompany pedaling. In the first, the chord unfolds into single notes. In the second, the chord is broken down into smaller chords, or a combination of smaller chords and single notes. Pianists should be aware of such architecture and its combinations, because while they are completely dependent on the right-hand pedal to produce their effect, the composer does not always mark them in the score. When there are no markings, the best way to determine pedaling is to reduce the open-textured strings to their closed position. Pedaling will then generally coincide with changes in harmony. In addition, harmonic factors must be taken into account so as not to create a sound that is too dense and lose the real bass.

Another reason to modify harmonic pedaling is the complexity of the right hand part. The lower sustained power of the treble compared to the bass will usually take care of this. But sometimes the sound must be diluted by means of a sort of half-pedaling that leaves the more resonant low notes still audible, and in extreme cases, the bass must be abandoned entirely and left to the listener’s ear so that the music is not muddy.

An example is Beethoven’s Moonlight Sonata, where the entire first movement is played. senzi sordini (without shock absorbers); that is, with the right hand pedal pressed without change from start to finish. On the modern piano, the results are hopelessly confusing. But with a third pedal, we can get pretty close to the effects Beethoven intended by pressing the lower notes of the piece with the middle pedal held down by the left foot throughout the movement. The right hand pedal is used as normal and switched as the harmony dictates. This allows the lower, undamped strings to act as sympathetic resonators, so that they vibrate continuously and produce a faint but audible mist of sound all the way through, through which right-hand singing can sound, as reported by the Beethoven himself, “like a voice from a vault”. (Read more about the history of the piano and the evolution of pianos.)

Various pedaling techniques may include these:

1. Press the pedal immediately after a note has been played and released simultaneously with the attack on a note, with the result that the second note joins the first in perfect legato, and without the slightest trace of blur or carryover in sound from one to another.
2. An earlier method, now used less frequently, is known as rhythmic pedaling. The pedal is depressed simultaneously with the attack and released just before a note is played. Legato may be a little less perfect, but the notes have a kind of boom due to the sympathetic vibration of the other undamped strings. This can be extremely beautiful on a slow cantabile.
3. A third type of pedaling can only be used after a silence. In it, the pedal is depressed before the note is played, with results very similar to those achieved with rhythmic pedaling.

Composers sometimes use staccato signs in combination with pedal signs. At first, this may seem like a contradiction in terms. What is meant is not that the pianist should attempt an impossible shortening of the notes, but that they should be played with the same touch and attack that is used for a staccato. This produces a slightly different tone when playing the same notes legato and pedal.

Pedal markings in romantic music should be interpreted discreetly rather than blindly followed. The pianist should try to guess what effect the composer was looking for and create that effect as close to the modern piano as possible.