'Tis the season of overfamiliar musical comfort food, so this unusual repast from one of the Northwest's premier vocal ensembles, the all-women early music group In Mulieribus ("amongst women"), is even more welcome than usual. The last millennium contains more 12th-month music than the carols you hear at the mall and, too frequently, the concert hall. The splendid sounds on the group's glorious new CD, A December Feast ($15), all associated with December liturgical feasts on the Christian calendar, range from 13th-century works to music by contemporary composers Maurice Duruflé, Peter Maxwell Davies and Portland's John Vergin.

Half the tracks originated in the 15th century or earlier, including the most substantial: shimmering "Sederunt Principes," by the great 12th-century composer Perotin, whose mesmerizing organum technique creates a rich tapestry of interweaving vocal lines. It's probably the most beautiful sound you will hear this season. Many early music groups excel at a single style, but In Mulieribus floats through ethereal medieval and modern works as expertly as it soars over more exuberant music by the great Renaissance composers Palestrina and Tomás Luis de Victoria, and a full-throated "Personent Hodie" adeptly arranged by Craig Kingsbury.

The reverberant acoustics of Portland's St. Stephens Cathedral, where the album was recorded in 2009, produce a serene, echoey sound that, thanks to the group's precision and smart choices by director Anna Song, never lapses into blurriness or gooeyness. Unlike some groups that strive for a uniform blend that sometimes descends into mashed-potato blandness, Song so adroitly balances the voices that we can bask in their rich harmonies while at the same time hearing each distinctive voice clearly.

While you're unlikely to have heard much of this music before, you'll certainly appreciate its stirring, comforting beauty. It's the musical equivalent of a hot toddy, ideal for a season that makes us crave musical warmth with a little kick. The group will sing some of this material, along with much more music from medieval monasteries, Renaissance cathedrals, and even the 20th century, plus some traditional European carols, in concert next Tuesday. It'll be the best classical concert of the season.


7:30 pm Tuesday, Dec. 21, at St. Mary's Cathedral, 1716 NW Davis St., 283-2913. $12-$20 at boxofficetickets.com.