Bodegues Sumarroca is a family estate founded by the Sumarroca family in the Alt Penedès, centred on their holdings around Subirats and the El Rebato estate in the hills west of Barcelona. The Letargia Gran Reserva draws on estate-grown Xarel-lo alongside Macabeu and Parellada, the classic Penedès trio, planted on limestone-influenced clay soils at moderate altitude. Farming across the estate is certified organic, with cover crops and careful canopy work to preserve acidity in a warm Mediterranean climate. The 2012 season in Catalonia was generally dry and warm, giving ripe but structured base wines from fruit intended for long lees ageing.

Grapes were hand-picked and whole-bunch pressed, with the base wine fermented in stainless steel to retain freshness and varietal definition. The cuvee was then tiraged and underwent secondary fermentation in bottle following the traditional method, laid down for an extended Gran Reserva maturation on lees well beyond the minimum thirty months, developing the toast, pastry and dried-apple autolytic character the wine is known for. After many years resting horizontally, the bottles were riddled and disgorged, and finished as Brut Nature with no dosage added, preserving the wine's line of acidity and dryness.