Lime oil & juice
Practical Action
The valve through which settled juice is drawn-off should be as near to the bottom of the vat as
is practicable in order that settled juice is not wasted. The height of the tap above the bottom of
the vat will depend on the amount of 'bottom' pulp which accumulates during settling. It is
possibly worth having several taps at varying heights above the bottom of the vat eg 3", 5", 9" to
ensure that one can draw off as much settled juice as possible.
The settling vats are also equipped with a bottom drain valve through which the still charge can
be allowed to flow into the still under gravity (if it does not have to be pumped), and through
which the vat can be drained during washing.
The sizes of the lime crop, settling vats and still should, if possible, be related, bearing in mind
that:
it is not advisable to fill a settling vat and thus disturb the settling, over more than a
couple of days.
the top pulp from a vat should ideally make one still load for distillation.
Working back from the still capacity, a still with a working volume of 500 gallons will take the
contents of a 1700-gallon settling vat (assuming that 30% of the settling vat volume is distilled
and 70% is settled lime juice). With efficient crushing a 1700-gallon vat would be filled with
the raw juice from 15-16 tons of limes. If limes are coming in at 10 tons/day then the vat will
be filled within 2 days. For the beginning and end of the season the vats of 850 gallons may
suffice and clearly a balance should be struck between large and small vats.
It is not good practice to keep adding fresh raw juice to vats which are partially full and have
started to settle. The settling is disturbed and the pulp which tends to break down during
settling can form a fine cloud which prevents a clear settled juice being obtained. It is not
advisable to take more than 2-3 days to fill a vat.
It is not recommended that top pulp be stored before distillation after the settled juice has been
drawn off, but this practice is adopted in some factories owing to lack of distillation capacity
and/or the use of very large capacity settling vats. Ideally, one would like to distil top and
bottom pulp from a vat as soon as the settled juice has been run off.
Addition of preservative is required, (sodium metabisulphite) to prevent fermentation if the drum
is to be stored or transported over a period of several months. Alternatively, there may be local
outlets for soft drink preparations where different requirements are needed, such as bulk-
storage. For shipment overseas, the single strength juice will be costly to transport in drums and
the juice may be concentrated to about 5 times for economy in transport costs. This requires
expensive equipment and consequently a high production level of juice is needed to offset the
capital costs of concentrators.
Lime juice
'Clarified' juice is settled or racked juice which as been 'polished' by passing it through a
clarifying filter. It is probably worth doing this to all settled juice in order to be assured of a
standard 'bright' product.
The settled juice is shipped in wooden casks (coated internally with paraffin wax) or suitably
coated metal drums and is preserved with SO2. It is important that wooden casks be washed
thoroughly and steamed before waxing. Coopering is important as juice losses can be high if
casks are not coopered up tight.
If the juice is to be stored for a considerable length of time, 900ppm SO2 is recommended
(350ppm is the legal limit in the UK for potable liquids but as single strength lime juice is
greatly diluted before consumption this level of SO2 does not present a problem).
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