Ca' dei Zago is the estate of the Zago family, established in 1924 and now run by Christian Zago.  Christian is besotted with naturalness and manages the property as if a self-contained biosphere.  All processes, whether it be composting, manure application (from their own cows), pruning, leaf-plucking or application of biodynamic preparations, are by hand, with the intention of producing the most natural end product.  Grapes are fermented plot by plot, using natural yeasts without temperature control, remaining on their lees until Spring.  To finish the wine, Christian bottles it with a little remaining sugar and some fine lees - col fondo - a process practised by the family since 1956, which gives this completely dry Prosecco its fine and long-lasting sparkle. The wine remains undisgorged and deposits a fine sediment and you can serve with or without (by gently pouring or decanting) the yeast.