Rapporto tra i costituenti volanti

"Relationship between volatile components"

As part of a research programme aiming at protecting and enhancing the Grappa from Trentino, they had been analyzed the constituents quantitatively more significant of 95 samples of Grappa produced from '74 to '77, according to the local traditional distillation systems, that is à bain-marie or in small baskets with direct steam. With the use of a prior extraction of volatile constituents of the grappa with pentane and methylene chloride and subsequent extract splitting on a silica gel column, it has been possible to expand the analytical field: it has been currently possible to identify and quantify through gas chromatography with capillary column over 80 components, mainly constituted by esters, alcohols, aldehydes and acids.

It has been tried to face first of all the relations between the characteristics of Grappa, especially the olfactory ones and its weighted volatile constituents. Observations and deductions are made by taking into account the results achieved in similar surveys on beer and whiskey. It is shown analytically as the dilution of raw grappa and the subsequent cooling implies the removal of the olfactory oily component. It has been also verified as the specific chemical addition of NaBH, both in the Grappa as in the extract, implies the elimination of the olfactory characteristics typical of the marc distillates, transforming it, in regards to this latter ones, in a product similar to the wine distillate. It highlights in this way the importance of the aldehydes presence in the Grappa for its peculiarity. There are therefore interesting perspectives of study on these compounds, in particular on some unsaturated aldehydes with an individual high molecular weight and the higher alcohols, the esters and acids seem to have a secondary importance for their olfactory characteristics.

Taken from Vini d'Italia (Wines of Italy), Year XXI, n. 122, September/October 1979.