Lime juice clear cordial
Practical Action
length and rotate inwards powered either by hand or electric motor. One roller is of a slightly
larger diameter than the other which provides a shearing action as the fruit passes through. The
gap between the rollers can be adjusted and maintained by heavy springs.
The production of lime cordial requires the juice to be clarified in order to produce a crystal
clear final product. Crude juice contains fruit debris and a cloud caused by fruit pectins. The
raw juice squeezed from the limes needs to be 'racked' - or allowed to clear thus allowing the
crude solid pulp to settle. Calcium carbonate is added at this stage. This reacts with the fruit
pectins and produces calcium pectate which settles with fruit solids.
In order to preserve the juice during this settling time, sodium metabisulphite must be added at
the rate of 3g/litre to provide a sulphur dioxide level of 1000ppm (parts per million). After
dilution with sugar syrup, described below, this level will drop to meet legal limits.
Racking can be carried out in a large wood or food grade plastic tank with a lid and a drain-valve
above the level of the solids that have settled. Racking time will vary, but three to five weeks is
normal. It should be noted that provided SO2 levels are maintained, the juice can be stored in
racking tanks for some considerable time, thus allowing a production unit to concentrate on
juice extraction during the height of the lime season.
Next the racked juice is
clarified by the addition of a
small quantity; 2.5g/litres of
calcium carbonate (chalk
powder) which precipitates
the pectin cloud. After the
addition of calcium
carbonate, the juice should
be allowed to stand for 48
hours, to settle. The main
problem at this point is to
judge the boundary between
the clear juice and the
sediment. Inclining the tank
as shown in Figure 2 will
make separation of the clear
juice more efficient.
Sight
glass
Clear lime juice
Batch preparation and
pasteurisation
The batch is prepared by
Sediment
mixing together clarified lime
juice and a previously
prepared sugar syrup, the
whole being pasteurised by
heating to 80ºC for 5
Figure 2: Lime juice clarification using the tilted tank
method - Illustration: Practical Action
minutes. At the end of this
stage it will be found that the
original sulphur dioxide level will be reduced so as to conform with the generally acceptable
legal maximum of 350ppm. The subtle flavour of lime is sensitive to heat and it has been
found that the following system, which minimises the heating time, gives a very acceptable
product.
A 50º Brix sugar syrup is made by dissolving 6.15kg of granulated white sugar in 10 litres of
clean tap water. When fully dissolved, the syrup should be strained through several layers of
muslin as even refined sugar contains tiny black specks. The syrup is then raised to boiling
point in a convenient pan that can be made from aluminium.
2