For many, César Franck’s reputation as a composer of organ music rests firmly on just a dozen pieces, the ‘Big Twelve’. These include the three late, great Chorals and the Pièce héroïque, all dating from 1868 until the year of Franck’s death in 1890. They are essentially concert works, developing monothematic material on a large canvas and designed to show off the quasi-orchestral capabilities of romantically voiced French organs.

However, there is another corpus of organ music comprising some 40 pieces, most of which were published posthumously under the editorship of Franck’s son, Georges, in 1905. These were designed as liturgical offertories, for parish organists ‘in the provinces’, whose instruments – often harmoniums – were more modest. Some of these pieces are tiny, no more than scraps. One ‘Amen’, for example, lasts a mere 15 seconds. A handful, though, are much more substantial, such as the Elévation in A major of 1859, a highly atmospheric concoction which floats along beautifully on the Voix Célestes.

There are half a dozen Offertoires which dominate the Pièces posthumes. That composed for Midnight Mass, based on the melody of the old carol Or, dites-nous Marie, is a delightful throwback to the Noëls of Dandrieu and Daquin. Other pieces, such as the Préludes pour l’Ave maris stella, were intended to be played at Vespers. Their simplicity and innocence are quite charming.

Under the hands (and feet) of Joris Verdin, playing on the Cavaillé-Coll in Saint-Omer’s Cathedral for the Ricercar label in May 2011, this widely varied compendium of music (in both quality and emotional range) is projected with a strong sense of devotional purpose, if not entirely note-perfect, creating a suitably devotional, incense-laden sense of atmosphere. The sound is slightly boxed-in, recorded at some distance, it seems, from the pipework.

In addition to the posthumous works he includes an ambitious untitled work in A major, discovered in the Bibliothèque Nationale de France, and published as recently as 1990. Dating from 1854, it is cast in five distinct sections, full of dramatic contrast, and makes a fitting end to an hour and three quarters of the younger pater seraphicus’s outpourings. For those who seek the complete Franck organ works, including Vierne’s arrangements of harmonium pieces, Audite has released a handsomely designed six-disc set of recordings dating from 2004-05. The instrument is the 1998 four-manual, 62-stop Goll situated in St Martin’s Church, Memmingen, Germany. Hans-Eberhard Ross rattles his way through the entire oeuvre with aplomb. As with Verdin, he has gone back to Georges Franck’s original edition of the posthumous pieces, instead of Tournemire’s drastically altered versions, published in the 1930s. One note of caution, though: Ross’s approach to the Chorals is on the brisk side. One yearns for more give and take, such as in Latry’s benchmark recording at Notre-Dame, Paris, for DG (nla). The Pièce héroïque, in particular, suffers from this impatience. At least Ross is note-perfect and the sound of the Goll is thrillingly spacious.