What it is
Shellac refers to all
forms of purified lac - a natural resin secreted by the tiny lac insect on
certain trees, principally in India and Thailand.
Known for three
thousand years, lac provided the natives of India with colors for clothing
and a material they fashioned into ornaments and trinkets. It first became
commercially important for the purple-red dye extracted from it to dye
textiles. It was prized as a decorative lacquer as far back as the
Aniline and other
chemical dyes have long replaced lac-derived dyes. However, despite the
many synthetic resins produced by the chemical industry, natural shellac
still retains an important place in the decorating products field as well
as in such diverse applications as pharmaceutical, candy and fruit
coatings; printing inks; furniture finishing; adhesives; grinding wheels;
hat stiffening; and paper and foil coatings.
Insects Make Shellac
Shellac is produced by a tiny red insect (Lac Laccifer) which, in its
larval stage, is about the size of an apple seed. Swarms of the lac insect
feed on host trees, commonly called "lac trees." Their
life cycle, of about six months, is devoted to eating, propagating and
making lac as a protective shell for their larvae.
During certain seasons
of the year, lac insects swarm in such great numbers that the lac trees
can take on a red or pinkish hue. When settled on the twigs and branches,
they project a stinger-like proboscis to penetrate the bark. Sucking the
sap, they begin absorbing it until they literally feed themselves to
death. At the same time they propagate, each female producing about one
thousand eggs before dying.
The sap the insect is
consuming during this period undergoes a chemical transformation in its
body and is eventually exuded. On contact with the air, it forms a hard
shell-like covering over the entire swarm. In time, this covering becomes
a composite crust for the twig and insects.
The female insect is
the main shellac producer. While she is exuding lac, she is preparing
herself to die after providing a fluid in which her eggs will mature and
from which the future supply of bugs will come, to repeat the process of
swarming, propagating and making the next season's shellac supply.
The males, having
fertilized the hordes of females, also begin their life-ending feast.
Although they contribute relatively little more to the shellac crop, they
have already assured an ample supply because the females vastly increase
their output of lac after being fertilized. The great mass of male and
female bugs on each tree gradually becomes inactive as the shell-like
covering forms over them. In the sixth or seventh month, the young begin
to break through the crust and swarm to new feeding grounds.
Shellac cultivation is
carried on to produce a large lac crop by helping the larvae find better
pickings for their feast. This involves simply cutting lac-bearing twigs
from an infected three a few days before the emergence of the larvae. A
bundle of such twigs, known as 'broodlac,"is tied to an uninfected
tree on which there are many tender new shoots. This results in a higher
survival rate of insects and a greater yield of lac since only a little
broodlac gives forth sufficient larvae to infect a tree thoroughly. No
further attention is needed until shellac is harvested.
Lac Is Harvested
Shortly after the young have swarmed at the end of the adults' life cycle,
natives begin to harvest the lac encrustation from the trees. Only one
crop is taken from a single tree. Young are hatched, however, twice a
Natives gather millions
of encrusted twigs, called "sticklac," for transport to simple
factories or refining centres where the encrustations are scraped off.
They may also break the encrustations off right in the forest or orchard
with a wooden mallet, much the way ice can be broken from around a tree
branch. This material is called "grainlac." In either case, this
is the first step in the harvest of shellac gum.
At refining centres,
sticklac is scraped to remove the resin from the twigs and then it is
ground (as is grainlac), usually in a primitive mill consisting of two
millstones, with the upper one rotated by hand. At this stage, the ground
lac contains a mixture of resin, insect remains (shells, excrement, body
parts), twigs and other
impurities. This is now passed through a coarse screen to remove the
larger impurities, like twigs.
After the lac is ground
and the chaff sifted out, it is soaked in water for several hours in large
cup-shaped jars. These are about two and a half feet high and have rough
serrated inner surfaces. Next a worker called a "ghasandar"
jumps into the jar and rubs the lac with his feet against the rough
surfaces. The object is to break open the lac seeds so the dye will flow
out and the insect remains will be freed from the resin. Dye water and
scum are removed in several rinsings. Then, the ground lac is spread out on
a concrete floor to dry in the sun.
product from this operation is known as "seedlac" from its
grain-like appearance. It is yellow to reddish-brown in color, depending
on the type of tree and the location from which it came. This is the raw
material from which both orange flake shellac and bleached shellac are
Even though most of the bright red lac dye is removed when sticklac is
washed, some shade of orange persists. When dissolved in alcohol, orange
shellac forms an amber-colored solution and the dried film has a
distinctive amber cast. For many uses, however, a colorless film
is preferred. To meet this market preference, the color is removed by a
The process involves
dissolving seedlac, which is alkali-soluble, in an aqueous solution of
sodium carbonate. The solution is then centrifuged or passed through a
fine screen to remove insoluble lac along with any dirt and other
insoluble material. Next step is bleaching the solution with dilute sodium
hypochlorite to the desired light color. The shellac is then precipitated
from solution by the addition of dilute sulphuric acid, filtered off,
washed with water, ground and dried in vacuum driers.
The final product is a
while powder commonly referred to as bone dry shellac, which dissolves in
alcohol to give a milky white solution. The opaqueness is caused by the
natural wax content of shellac which settles out on standing, leaving a
clear solution above. The wax is easily re-dispersed and should be stirred
back into suspension before use. Solutions of bleached shellac have
traditionally been called "white shellac" to distinguish them
from orange shellac solutions. This is somewhat of a misnomer because they
dry to a clear, colorless film.
Clearly, lac, and anything that is coated with lac/shellac is tame’.
Lac is called by many names in the food processing industry, some of which
- Food Grade Wax
- Confectioner's Glaze
- Food Glaze
One should keep in mind
that Rabbanites permit the consumption of lac. Therefore, many foods
which bear a "kosher" label may contain lac, and would therefore
be tame’ (not kosher).