6.1 Commercial distillation
Once the addition of the botanicals is complete, the actual distillation begins within the copper still (Figure 4). The still is heated to a sufficient temperature to start boiling. If you recall from our laboratory still earlier, once a sufficient temperature is reached to enable a single component of the mixture to boil, this component alone boils, evaporates and condenses. In doing so, it is separated from the remainder of the mixture which has not yet reached boiling temperature.
The same principle is operating here in the production of gin, but on a much larger scale. Initially when the still is heated, the first distillate to appear is called the ‘heads’ of the run – it is quite harsh and astringent and often contains impurities so it is discarded.
The middle or ‘hearts’ of the run is the only distillate that is used by the distillery to produce their gin and it is carefully collected. A drop in the % ABV is usually an indication of the end of the hearts component of the distillation.
The final section of the run is the ‘tails’, and this is also discarded. By being selective in this way, only the finest part of the run makes it into the final gin. This does, however, mean that only small quantities of gin can be produced from a single distillation run, but the quality of this gin will be superior.
At what temperature do you think the hearts of the run distils?
As the distillate is composed primarily of ethanol, this will boil at a temperature of around 78°C.