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feints its flavour will be uncharacteristically thin and insipid and taste of raw alcohol.
After the middle-run is completed, it s important that the entire middle-run be placed in a
single container and thoroughly mixed. This, when diluted, is the finished corn whiskey.
The remaining distillate is the tails and should be collected until the still-head temperature is
about 82oC (179.5oF). The end of the tails phase can also be determined by tasting a few
drops on a spoon. When all the acrid and bitter flavours yield to a grainy watery sweet
flavour, then switch the still off. The spirit-run is complete. The tails should be transferred
to the container labeled Corn Feints where they are mixed with the heads, and are
collectively known as feints .
Do not empty the residue out of the boiler until you are sure you are satisfied with the
whiskey. If you inadvertently spoil the middle-run by misjudging the transition points
between heads and middle-run or between middle-run and tails, you can simply return the
heads, middle-run (diluted or not), and tails to the residue in the boiler and redo the entire
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spirit-run. There is no need to return the foreshots. The subsequent run can be executed
without that phase.
The spirit-run can be rerun in this manner several times if required, which is often necessary
for a novice distiller becoming familiar with the transition points. This rerun can even be
done when a significant portion of the middle-run has been consumed during evaluation. The
middle-run cut will just be smaller.
In the tables at Figures 2, 3, and 4, which are data from actual spirit-runs, you will observe
that each run records a loss of alcohol around 10-14%. This loss is almost entirely due to
alcohol left in the boiler after the still is switched off.
A fractionating still of this design does not need to sustain a loss anywhere near this
magnitude. The only reason it occurs is because the distillate that emerges after the stillhead
temperature is 82oC (179.5oF) is not usable in subsequent whiskey distillations. In other
words, above 82oC (179.5oF) the distillate is not suitable for tails and therefore cannot be
mixed with the feints.
If the tails were collected all the way up to a stillhead temperature of 97oC (207oF) the tails
would contain almost all the fusel alcohols and heavier compounds. The concern here is that
after repeated distillations where the feints are recycled through numerous spirit-runs, the
fusel alcohols would literally accumulate from batch to batch, to the extent that the feints
would become contaminated with such a high concentration of fusel alcohols that it would
pervade into the finished whiskey.
This would not only spoil the flavour of the whiskey, but would predispose the whiskey to
causing bad hangovers. A condition normally avoided when making whiskey in a high-
separation still.
However, all is not lost. If the operator were to create a fifth phase, namely the redistill
phase, all the distillate after the tails could be collected in a separate container labeled
Redistill .
The redistill could not be used in the production of whiskey, but once it had accumulated to
10 or 20 litres (2½ - 5 US gallons) it could be redistilled in the spirit still in a manner that
rectifies it to pure alcohol. The alcohol could be used to make gin, vodka, or essence-based
spirits. It could also be used as grain neutral (i.e. approximately pure alcohol) to be diluted to
40 - 50% alc/vol and blended with whiskey to adjust the intensity of its flavour. This will be
discussed later.
When the spirit-run is complete the packing in the column will be flooded with tails. These
should be thoroughly washed from the column by pouring generous quantities of boiling
water down from the top.
Next, the boiler should be drained and flushed. This can be done by attaching the drain-hose
to the bottom ball valve and leading the tube to a floor drain then opening the valve. After
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the boiler has drained it can be flushed by attaching one end of the flushing-hose to the upper
ball valve and the other to a tap with a garden-hose thread. Open the upper ball valve and
turn on the tap for a few seconds, let it drain, turn on the tap again, let it drain, and so on until
it s flushed.
Flow Rate: In the spirit-run procedures documented in Figures 2 and 3 above, the flow rates
were set very low. This was done to slow the rate that the transition points occurred to allow
novice distillers an opportunity to familiarize themselves with identifying them and
switching the phases. The low flow rate results in the spirit-run operating at a relatively high
level of separation. And, this is evident in the alcohol content of the tails (e.g. 82%). In a
gooseneck still the tails are typically between 50 and 70% alc/vol. At the relatively higher
level of separation the tail congeners are passed across while the water and fusel alcohols are
held back. In the end the same spirit is produced but with less water and fusel alcohols.
However, there is no question that there are subtle differences between whiskies distilled at
differing separation levels.
When you are comfortable with identifying the transition points and switching the phases,
you can start running the flow rates considerably faster, even to the point of having the
distillate flowing continuously from the still (i.e. not dripping). However, the foreshots
should still be taken off at no more than one or two drops per second. The heads should run
a little slower than the middle-run and tails, but many distillers run the heads at the same rate.
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