The Compleat Distiller

THE COMPLEAT DISTILLER 30
The Immersion Element
An immersion element is mounted through the side of a boiler
and is in direct contact with the liquid. Electric water heaters
use immersion elements. If the element is larger than needed,
it will require direct and sophisticated power control to avoid
surge boiling. A thermostat in the boiler will NOT prove
satisfactory. (Thermostats work in water heaters because they
operate well below the boiling point).
Fig. 3-7
Indirect Heating
An indirectly heated boiler is supplied with heat that is generated elsewhere, and then transferred to the
boiler in a well-controlled manner. Frequently, the laws of physics control the temperature and the rate
of heat transfer (for example, you cannot provide more than 100ºC with hot water. This prevents
burning in cooking, and is particularly suitable for processing botanicals or thick mashes, which might
be ruined by higher temperatures). The two main methods of indirect heating are jackets and coils.
The Bath or Jacket
The boiler is held inside another container that holds heated
liquid or steam. The arrangement can be two separate pots (like
a double boiler), or a shroud or channel permanently mounted to
the outside of the boiler. The jacket can be directly heated itself
(again, like the common double boiler), or fed with hot liquid or
steam from a separate boiler. Jacketed heating vessels are very
common in industry.
Fig. 3-8
Indirect heating
A coil of tubing is mounted inside the boiler, in direct
contact with the liquid. Hot liquid or steam flows through
the coil, heating the boiler’s contents. This arrangement
requires a separate heat source, and is also common in
industry. This is equivalent to an immersion element, but
the rate of heat transfer and the highest temperature the
boiler’s contents are exposed to tend to be lower.
Fig. 3-9