Selection, preservation and fermentation of pomace
The process of distilling Grappa is what makes it unmistakably unique, as it derives directly from a solid raw material, pomace, which contains everything left over after grape pressing: skins, stalks and seeds. The skin is what covers the grape flesh and is the part of the cluster that contains most of the aromatic substances which compose the personality of Grappa from the start of its production.
Before starting the distillation process, it is important to make sure that the pomace is fresh and well preserved. The quality of the raw material is crucial for obtaining a fine spirit because any deterioration would affect the final product. The qualities of different grapes and the process employed give rise to unique grappas with a strong personality and many nuances of bouquet and aroma.
The types of pomace that give rise to Grappa are those that contain alcohol following the fermentation process. In fact, for the production of distilled spirits, it is essential to start with a fermented product, or a substance that already contains alcohol. During the fermentation process, the sugar contained in the pomace is transformed into alcohol by yeasts. Whether or not a pomace is fermented depends on the type of wine-making process from which it is derived.
Pomace from the production of red and rosé wines is already fermented or semi-fermented, respectively, and ready for distillation. On the contrary, white wine pomace is called “virgin,” because it is not left to ferment in the must and therefore has to be fermented before starting the distillation process.
Once the pomace is fermented, the actual distillation process begins. Distillation is a physical process used to separate the volatile substances of a fermented product according to their different boiling points. In essence, through heating in alembics, the distiller vaporizes and separates the various components of the pomace and then recovers them in re-condensed liquid form by lowering the temperature.
Distillation of the pomace may be continuous or non-continuous and must be carried out with less than 86% by volume. Within this limit, the product obtained may be redistilled.
Each of the two instruments provides a distillate with different characteristics, but only the art of the master distiller allows to obtain the Grappa, the precious spirit of the Italian tradition.
Non-continuous-cycle artisan distillation
The distillation process uses non-continuous alembics, among which we have:
- Alembics with flowing steam fueled boilers
- Bain-marie alembics
- Direct fire alembics
The entire process is controlled by the master distiller who has perfect knowledge of both the raw material (pomace) and the working tool (alembic).
The distiller fills the alembic’s boiler with fermented pomace and begins to heat it, making the volatile substances – such as alcohol, water content and unpleasant substances that are to be eliminated – evaporate from the mass.
Rectification is the process by which unwanted substances are separated from the rest of the distillate. This process requires the skill and ability of master distillers who, based on their experience, can divide the distillate according to its components and the qualities of each part into head, heart and tail.
The head, the first part of the distillate that leaves the alembic, is eliminated because it contains both toxic methyl alcohol and some unpleasant and acrid odors. Thanks to its abundance of aromatic substances and ethyl alcohol, the heart – the central part of distillation – is the component from which the final product is obtained.
The last part flowing from the alembic is the tail which, because it is full of oily substances, must necessarily be eliminated.
The distillation process is complex because recognizing the beginning and end of each stage requires a skill possessed only by the most experienced distillers.
It allows distillation of large quantities of products without interrupting distillation. Basically, the distillery consists of two columns divided into “hollow” rooms. The first column is called “analyzer” the second “rectifier”. The column called analyzer has the function of concentrating the distillate product, while the column called rectifier has the function of separating the various components, i.e. the head, body and tail.
The product to be distilled, which is partly already preheated, is placed at the top of the first column and steam is inserted from the bottom of the first column water. The encounter of these two components causes evaporating elements to bond to the steam; they are thus transported to the second column, where the alcohol and water steam rise upwards.
Both the decrease in the steam temperature and the presence in the column of the intermediate plates allow to condense, as it ascends inside the column; first the heaviest components (the tails that will be discarded from the lower part of the column), then the heart, which will be harvested, and then the lighter parts (the heads that will be discarded from the top of the column).
From distillation to bottling
The product obtained at the end of the distillation stage is not suitable for human consumption due to its high alcohol content.
Subsequently, according to the characteristics the producer intends to give to the final product, the Grappa then undergoes further processes. All phases of processing are state-of-the-art, following methods developed and consolidated in Italy over centuries, and it is only at the end of this traditional process that the product acquires all the characteristics necessary to obtain the Grappa GI designation.
The process following distillation is to reduce the alcohol content, which is important because this gives the distillate a balanced taste and aroma. This operation implies diluting the distillate with water until the desired alcohol content is reached.
Depending on the manufacturer’s choices, dilution may be followed by aging, in which the Grappa is left to rest in wooden barrels. Not all the distillates undergo this treatment, as in the case of young grappas.
The Grappa production process concludes with filtration. To facilitate the process, the distillate is initially refrigerated and taken to a temperature between -4°C and 15°C. Subsequently, actual filtration begins with the elimination of the oily substances which form with the addition of water.
The Grappa becomes a transparent, crystal-clear spirit ready to be bottled.