This is an exceptional type of batch distillation plant and, since there are only a few such systems in Italy, it is visited by grappa enthusiasts from all over the world.
Using a “bain-marie” or “water bath”, as most chefs will know, means that the pot of the grape pomace is not heated directly by fire but it’s surrounded by another pot of boiling water that allows to heat the grapes gently, preventing the grappa from taking on an unpleasant smoky or burnt taste and permits a slow evaporation. Thus, retain the wine-like characteristics of the grape skins.
Their system is called “Piedmont pot still or Piedmont alembic” because this is a brevet of a local copper craftsman. This is the only bain-marie grappa distillation plant in which the grape skins that the master distiller puts in the pot don’t need to be wet using additional water or marc but they get distilled as they come with their natural moisture.
In Distilleria Gualco’s case “the alembic” holds around 200 kilos of grape skins and in just an hour produces from 10 to 15 litres of grappa of 55/65% vol.
The system, as a certificate that’s been hanging in the distillery for 100 years states, uses “Semigasogeni Autarchici” (Self-sufficient fuels) and the combustible used is the same grape-skins which have already been used to produce the grappa.