The distilling process

The distilling process begins with noble raw materials, grains, which are initially ground in order to make a mash, and it is at this point that the starch is converted into sugar. The fermentation process then follows. Finally, the fermented mash is distilled twice and depending on the grains used, either the powerful malt wine (the base for all grain genevas) or the grain alcohol is obtained. Today St-Pol is the only distillery in the low lands that still distils grain alcohol, besides malt wine.

The well-balanced and subtle composition of these two components is responsible for the ultimate smooth and fine texture of our 100 % grain-genevas.

The distillery is equipped with a mill, two distillation columns, a rectification column and a still pot.

The Grinding

The mill is located on two floors above one another. The grains, delivered in bags, are lifted through a trapdoor to the upper floor and emptied into a rotating brushing machine in order to separate the grains from the chaff. The grains are then pulverised by the hammer mill and the resulting flour is blown into 3 hoppers with a capacity of 1.200 KGs each.

Ingredients for the malt wine are rye, malt (barley) and maize, for the grain alcohol, wheat and malt.

The saccharification of the starch

The flour is mixed with water in the mash tun - capacity 2.900 L. The mash is brought to boiling point by direct addition of steam, after which the mash is cooled down to approximately 69° C. Through the addition of malt - germinated barley - the saccharification process is induced and will continue for about 1 hour at a temperature of 61° C. The mash is then cooled down to 30° C and pumped into fermentation tanks.

The fermentation process

The fermentation room contains 4 tanks with a capacity each of 10.000 L. The cooled mash, after being pumped into the tanks, is mixed with water to reduce the sugar concentration. Without the dilution of the mash with water, the yeast would perish due to a high alcohol concentration, hence resulting in an incomplete conversion of the sugar into alcohol.

Baker’s yeast added to this mixture, results not only in the transformation of sugar into alcohol and carbon dioxide, but also in the production of other aromatic components. Fermentation lasts about 72 hours.

The distillation process

The fermented mash is pumped into a condenser where it is pre-heated before reaching the top of the distillation columns. Each of our two copper distillation columns are about 6 meters high and contain as much as 15 plateaus which provide for an equal distribution of the mash and the steam injected below.

The heating of the fermented mash causes the alcohol to evaporate (boiling point 79°C). The rising steam, used to pre-heat the mash, takes with it the volatile components, which are cooled down in the first condenser. The second cool water condenser cools to room temperature.

The residue or draff flows from the bottom of the columns into tanks. These residues are a natural and nutritious waste product that will be used as fodder for cattle.

The phlegm (first distillation) contains about 57 % vol of alcohol and flows into a measurement tank located in a sealed area. Only excise clerks are allowed to unseal this area, which they do in order to determine the exact quantity of alcohol produced. The phlegm is then pumped into storage tanks, awaiting further processing.

A second distillation process results in the conversion of the phlegm into malt wine trough a discontinuous process in a still pot, or grain alcohol through a continuous process in a rectification column. The production process for these two products is the same up until the measurement tank located in the sealed area. Only the grain recipes are different.

Reference :
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