Poli Museo della Grappa

Poli Grappa Museum

Poli Distillerie

Poli Distillerie

Arguments index


The distillation process begins by filling the still boiler up with fermented grape pomace and then proceeding with their heating. The first stage allows the volatile substances, alcohol and water, to evaporate from the bulk. The ethyl alcohol, (i.e. one of the distillate's main components) boils at 78,4 °C instead of 100 °C as water does. However, being the ethyl alcohol dissolved in water, its boiling point may vary according to its concentration into water. The most the water concentration is, the highest will be the alcohol boiling point SOSTITUIRE CON ( greater is the amount of water and higher will be the boiling point). The grape pomace contains other volatile substances which evaporate and merge with the distillate. A lot of them are displeasing, therefore undesired, consequently meant to be eliminated. Thankfully, the various volatile substances of the grape pomace evaporate at different level temperatures. However, thanks to an accurate checking on distillation process, it will be possible to eliminate the unwelcome components by keeping all quality substances. This separation, or elimination of displeasing substances is named rectification and it is carried out by means of a head and tail cut on the distillate. The alcoholic steams produced by grape pomace heating are consequentely concentrated, cooled and brought to the liquid state, giving rise to the distilled product. The distillate is divided into three parts according to its components and quality: head, heart and tail. The head is the first part of the distillate getting out from the still: it mainly contains some substances giving Grappa such an unpleasant flavour, besides a small part of methylic alcohol, which is toxic, so meant to be eliminated. These substances luckily have got an evaporation point lower than the "noble" substances of Grappa, so they are the first to be produced. The skill of distillator consists in defining the right time the head of the distillate comes to an end in order to let the heart, the richest part of Grappa made of ethylic alcohol and aromatic substances come out. Moreover, the distiller must be well qualified to recognize the end of the heart and the beginning of the tail, that is the final part of the distillate containing greasy and oily substances. Summing up, the distillates are obtained through the selection of heart, rich of ethylic alcohol and pleasant aromatic substances, then taking the head and the tail away, so the starting and final parts of distillation process.

Fonte: L.S. Lenormand, L'Art du distillateur, Parigi 1817.