Distillation (First and Second)
Distilling twice, the six traditional direct-fired copper pot stills, the largest on Speyside, transform the cloudy 'wash' into the crystal-clear new spirit required for maturing into the finest Glenfarclas Single Malt Scotch Whisky.
Many modern stills are heated internally by steam filled unit heaters. This method heats the 'wash' more gently, thus increasing the life span of the still. However, the final flavour can be different, and Glenfarclas continue to use traditional 'direct fired' stills.
The larger 'wash stills' are required for the first distillation and smaller 'spirit stills' for the second distillation. Characteristic of direct fired stills, each wash still has a 'rummager' fitted inside. A 'rummager' is a rotor arm, with chains lining the inside of the still. As it rotates, the wash is prevented from sticking to the still.
25000 litres of 'wash' are pumped into the wash still for the first distillation. The wash is heated to 85 degrees C. Alcohol has a lower boiling point than water, and the resulting vapour condenses back into liquid in the condensers, positioned on the outside wall of the Still House, and collected as the low wines, containing 23%abv. This accounts for 40% of the distillation, the remaining 60% being pot ale, the yeast rich residue containing 0.1% per cent ethanol. This is reduced into syrup, which can be sold to make animal feed.
SECOND DISTILLATION (Foreshots, Heart, Feints)
Foreshots ( first 5%)
Collected for the first 20 minutes of the second distillation, the foreshots contain highly volatile compounds, which would destroy the flavour balance and the quality of the final product.
Heart (next 15%) approx. 4000 litres
Starts at 72%abv.
During the next 3 – 4 hours, the crystal clear new spirit is collected. The timing of changing to the middle cut is vital and will affect the final flavour.
Feints (next 40%) approx. 8000 - 9000 litres
Starts at 60% abv.
For the next 4 – 5 hours, the remaining alcohol is collected, and mixed with the foreshots. Added to the next batch of low wines, this forms a new charge for the spirit stills, thus ensuring efficient ethanol removal.
Spent Lees (last 40%).
Once the alcohol is driven off, the remaining distilled water is treated and re-oxygenated in a treatment plant, after being discharged from the still.
Copper acts as a catalyst for ester production and precipitates lipid material, thus improving the clarity of the new spirit. Stainless steel does not offer these properties.