Lime oil & juice
Practical Action
The potassium (or sodium) metabisulphite is best dissolved in water in a special tank and the
solution of SO2 of known strength admitted into the lime juice casks or drums.
Settled lime juice (preserved with SO2) has been shipped successfully from the West Indies to
the UK in 250 gallon Transit-tanks which are constructed of high density polythene supported in
a steel frame.
Lime oil
The top/bottom pulp charge is distilled to obtain the lime oil. A good quality lime oil is generally
one which exhibits a low optical rotation (ca + 38°). The optical rotation decreases as the
duration of the distillation increases. Aroma/flavour quality of lime oil is associated with an
increase in oxygenated constituents. Some of the oxygenated compounds are produced during
the distillation when the lime oil is exposed to high temperatures in an acid environment.
The distillation unit should comprise of a still pot, about 750 gallons working capacity, together
with condenser and oil collection systems. Stainless steel is preferred for construction of the
equipment, as it is resistant to corrosion and non-reactive to the oil. A suitable boiler for steam
generation will be required and this should have an output of at least 500lbs of condensed
steam an hour, high pressure steam is not required. An adequate volume of steam generated at
low pressure is the main requirement.
The still contents should be warmed-up on the closed coil until distillation commences and then
the closed coil is turned off. Distillation is continued by use of the open steam coil ('sparge'),
which if lagged properly has the effect of maintaining the liquid level in the still, at about the
same height throughout the distillation. In this way the possibility of the charge overheating is
avoided. Distillation rate, and time of distillation is dependant on still and charge size.
Still cleanliness is very important. The inside of the still should be regularly scrubbed out to
avoid the build up of lime residue on the walls and more particularly the steam coils. After
cleaning the still should be steamed out until no unwanted odours remain.
To avoid a build up of pulp inside the open steam coil a slight flow of steam is passed through it
whenever the still contains a charge.
Distillation equipment
The still works at only a little above
atmospheric pressure (stills will often be
equipped with safety valves which are set at
5psi.
It is occasionally worth considering using a
water sealed top, as the gasket seals which
are widely used, suffer from the drawback
that gaskets wear out and must be
replaced. This is not always easy in remote
areas.
Figure 1: Condenser
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