As I began thinking about composing a piece for William Peterson and Pomona's new Fisk organ I found myself returning to certain intervals, mostly rising whole steps topped off by a half-step. At some point it came to me that these are the intervals of "Es ist genug" a Lutheran hymn tune written by Johann Rudolph Ahle in 1662. The melody is well-known, principally from Johann Sebastian Bach's chorale setting and from Alban Berg's quotation of that setting in his Violin Concerto. The tune is beguiling and unusual in its opening intervals and its phrase structure, which leave us floating in the key of the dominant far longer than the "central" key.

Upon further reflection, abstract intervals were out the window, and it was clear that I should use this tune as a basis for the piece. The resulting Variations on "Es ist genug" is just what the title implies. It divides into 11 short sections, each with a self-explanatory descriptive title. The progress of the melody is perceptible throughout each variation, but rather than depending on the time-honored technique of using the underlying chords as a unifying device, the piece uses the melody as a sort of serial row. Virtually all of the material in the piece is directly derived from the intervals of the melody, the one exception being the ninth variation, which quotes Bach's inspired setting and reflects Berg's poignant paraphrase. Otherwise the original melodic intervals coalesce into the chords, counter melodies, and the textures which comprise the piece.

The Prelude spins out a splashy texture based on the first five notes of the tune, which then appears in its entirety in the pedal. Scherzo treats the tune in a pointillistic and rhythmically quirky manner. Meditation similarly spreads the melody over a wide range, but sustains collections of notes into chords. In Trio the central voice plays the melody while the other two parts obsessively ruminate on the opening five notes in various transpositions and rhythmic patterns. Declamation is a short strident fanfare, which races through most of the melody only to hold on to surprising pitches. In Lullaby the melody is most straightforward in the pedal, while other versions move at different speed in the manuals. Grand and Pompous certainly is. With Growing Momentum returns to obsessive treatment of the opening intervals, in several simultaneous tempos and meters, and serves as a giant upbeat to Es ist genug: Bach's setting, with connecting lines reflecting Berg's paraphrase in his Violin Concerto. In Shimmering the melody is doubled at intervals based on the opening, while the walking bass line reflects the same intervals. The Postlude is an expansion of the Prelude, and serves to bring the piece to an exuberant conclusion.

Variations on "Es ist genug" was commissioned by Pomona College for the inaugural series of concerts featuring the College's new Fisk op. 117 organ, and is dedicated to William Peterson.