Frontignac grapes are harvested at a minimum 14° baume of sugar ripeness, crushed into open fermenters and partially fermented on skins for a week and more to extract maximum colour and flavour. This gradual fortification of around two per cent alcohol per addition helps control fermentation and ensures seamless wine and fortification integration. To control the development of aged rancio characters and to keep the flavours fresh and balanced, batches are matured in larger oak barrels than those used for tawny ports, well seasoned oak, at least ten years of age. This allows the wine to slowly develop complexity without obvious oak flavours and characters. The final blend is cold stabilised and filtered prior to bottling.