The Compleat Distiller

THE COMPLEAT DISTILLER 36
Types of Still
The Pot Still
The Pot Still is the simplest possible still, consisting of a boiler (or
evaporator) directly connected to a condenser.
The Survival Still and the laboratory retort both qualify as pot stills.
A more sophisticated pot still will have a boiler (usually electrically heated)
with a tight-fitting lid and short tube to carry the vapor to a condenser. The
alembic, with its very long spout, used air for cooling, but
modern stills usually use water cooling. This simple, straightforward design
makes the pot still attractive.
The disadvantages of a pot still are that the strength of the product can be
fairly low, and it does not do a good job of separating out the congeners.
Fig, 03-18
Typically, a pot still will produce 35% ethanol from a 10% wash. Early in the run, the concentration is
higher, starting at about 60%. The concentration drops steadily throughout the run as the ethanol is
removed from the boiler. We discuss this effect thoroughly in Chapter 4.
You can discard the first part of a run, containing the most volatile congeners, (called heads), and stop
the run when the less volatile ones (called tails), start to appear, but the middle portion of the distillate
will still contain a fairly high proportion of them. These materials help produce the true flavor of
whiskey, rum or brandy, but a more sophisticated still offers greater control over these trace
components.
The traditional Whiskey Still
You can increase the final concentration of ethanol by
re-distilling, and this is exactly what is done in
practice. Two or even three distillations are done
before the product is ready for storage and maturation.
This traditional process works well, but is time and
labor intensive. Re-designing the still can save a
considerable amount of both, by creating reflux.
Whiskey stills are large copper pots topped by
lovingly crafted copper alembics. Each distillery has
its own unique alembic design, perfected through
years of trial and error. These designs are carefully
maintained and duplicated, even down to all the dents
and blemishes. In the complex environment of a still,
very small changes can have very large effects.
Fig. 3-19
Tradition and beauty are not the only reasons for using copper. Several distilleries have tried
substituting stainless steel for copper, with bad-tasting results. Changing some of the parts back to
copper restored the proper taste. Both physics and chemistry are involved in the process.
The alembic domes are not insulated, and are deliberately left open to the air for cooling. Vapor
condenses on the inside surface to form liquid reflux, and this in turn re-evaporates, with the result that
vapor becomes stronger and the reflux weaker. This process, called "fractionating", can repeat itself
many times in a good whiskey still.