Lime or Choona

The word “lime” has three meanings. It is a sour tasting fruit, a sticky adhesive used to snare birds, and calcium carbonate.

Calcium carbonate can be of mineral or animal origin: limestone, chalk, sea-shells, molluscs, oysters, clams, mussels, snails, coral, pearls and egg-shells.

Heating removes carbon dioxide and converts the calcium carbonate to calcium oxide. Also known as quicklime, burnt lime and pure lime, calcium oxide is inedible.

Calcium oxide treated with plenty of pure water in a controlled environment (slaking of lime) produces calcium hydroxide or edible lime, also called pickling lime or choona/choonam, commonly used in paan. It is also utilised in the production of the sweetmeat called petha.

The chemical compound calcium carbide is produced from a lime and carbon mixture. Calcium carbide (popularly known as masala), carbide gas, acetylene, ethephon and ethylene gas are all banned by the Government of India for artificially ripening fruit.

Acetylene (mentioned above) mainly used for gas welding, is made from calcium carbide. Calcium cyanamide is also made from calcium carbide and is used as a fertiliser, in steelmaking processes and carbide lamps.

Calcium hydroxide together with chalk produces a low cost material for whitewashing walls and disinfecting drains.

Lime mortar consists of lime, sand and water. Where limestone is unavailable, sea-shells are utilised. Coral, poached off the Tuticorin coast, is said to be illegally used as building blocks in place of granite, raw material for the preparation of lime, mortar and cement and for the manufacture of calcium carbide.

Tabby was a building material consisting of lime, sand/gravel, water, and crushed oyster shells. Today, artificial tabby is made using Portland cement in place of lime, but it continues to contain shells.

Production of ithil in Kerala

A choona or lime factory in Kodungallur, Kerala informed Beauty Without Cruelty that the primary source of choona (calcium carbonate) other than mining (limestone) was from marine organisms, i.e. sea shells or kakka in Malayalam.

These living shells or marine animals are collected mainly by women from sea shores and backwaters of Kerala. The collection of kakka is a common occupation in the coastal belt of the Arabian Sea covering places like Kollam, Alappuzha and Ernakulam districts.

The flesh of the live creatures inside the shells is scooped out and sold for a good price in the meat market, whereas the shells are sold to the choona factories in the region which pick up huge quantities.

At these factories the shells are mixed with charcoal and baked in a kiln. The foul smell during baking is because the shells have a thin membrane-like coating. Twenty-four hours later the shells are transformed into ithil – the local name for choona or calcium hydroxide.

Choona is mainly utilised as edible lime, an ingredient used in paan, as an insecticide (particularly on tea estates), for whitewashing walls and as a cleaning agent in waste water treatment systems.

Production of Sipo chuna in Odissa

Ganjam is where the lime industry of Odissa is situated. Marine mollusc shell lime preparation which is indigenous and crude, is much preferred because shell lime putty remains okay for 2 months, whereas the stone lime becomes hard within 2-3 weeks.

The lime produced from the shells of molluscs is called sipo chuna in Odissa. By heating shells quick lime is produced. Hydrated lime is the reaction of this quick lime with water. If more water is added, it becomes dahi chuna or milk of lime i.e. lime putty.

Different types of mollusc shells (bivalves) like khola sipo, gondhi sipo, pati sipo and genda (snails) are utilised – snails being the most. Locals collect these shells. The method of collection and lime preparation has been passed down over generations.

The burning unit or klin (bhati and chula) that is specially constructed in the open (although surrounded by settlements resulting in harmful pollution for people who live there) in an east-west direction for burning mollusc shells also has a fan, and wheel; and then there is the slaking pit (kunda). The charcoal used is collected from kewda and liquor distilleries or by burning forest wood.

Lime is very corrosive to human skin and the burning, slaking and packing need to be carefully handled. Shells and charcoal are washed and usually mixed in a ratio of 2:1 for lime putty and 1:1 by volume for dry hydrated lime (powder lime). However, the highest amount of charcoal is used for khola sipo due to its thick and large shell size. Gondhi and genda consume more charcoal than pati sipo due to their hard, compact shells. A single burning takes 3 to 4 hours.

For 100 kgs wet lime about 48 kgs of shells are required; and for 100 kgs of powder lime about 117 kgs of shells are required.

Lime of shell origin is used for white washing – the demand for lime putty is decreasing as people prefer to use distemper.

Cheriyal scroll paintings of Telangana utilise white colour derived from sea shells. That they are painted with squirrel and goat hair brushes is another cruel issue.

Khola and gondhi are the shells mainly used for preparation of items put in the mouth (since they can cause damage) like gudakhu (a pate of tobacco leaf, lime and some sweetening agent), nasa (snuff powder of tobacco leaf and lime), khoini (tobacco leaf and lime), and paan (betel leaf, lime and other ingredients).

It is also used as an agent to increase the alkalinity of fishponds, as a water purifier in dug wells and for hygienisation of sewage sludge, as well as an ingredient in the preparation of cement and bleaching powder.

Many more Uses

In fact, BWC found out that calcium hydroxide is much more widely utilised than stated above. However, there is a chance of the source being limestone and therefore mineral in origin. The tanning industry uses it for liming hides and skins. The food industry uses it for processing water, e.g. soft drinks. The petroleum refining industry uses it as an oil additive. The road construction industry uses it for soil stabilization. The paint industry uses it as filler in the preparation of dry mixes. The paper industry uses it as coating pigment. The pharmaceutical industry uses it in the form of calcium carbonate, an ingredient in antacids and toothpastes, and as a calcium supplement.

Calcium of shell origin – often termed organic – is extensively utilised in Allopathy, Ayurveda, Siddha, Unani and Homeopathic products despite the use of sea shells attracting a minimum of three years imprisonment under the Wildlife (Protection) Act. And, the glass industry use both calcium oxide and calcium carbonate.

Calcium carbonate is also used in the manufacture of linoleum. Incidentally, it was discovered by accident in 1861 when linseed oil oxidized into a ‘skin’ from a can of paint. Linoleum is made from linseed oil, tree resin, powdered wood and cork, limestone or calcium carbonate (used as filler) and pigments with a backing made from jute. Vinyl is not the same as linoleum except that they both come in sheets and cover floors. Vinyl consists of felt, fibreglass and dyes. Ethylene derived from crude oil and chlorine found in regular salt processed together result in Poly-Vinyl Chloride (PVC) resin.

Chewing over Choona

In fiscal year 2017, the volume of shell lime production in India was 12.34 metric tons; in 2018 it was 10.89 metric tons; and was estimated to decrease to around 7.66 metric tons in fiscal year 2019.

The heart-shaped betel-leaf/Piper betel/paan creeper is cultivated and consumed in many parts of South East Asia. It is also called paan when filled with ingredients and, typically, folded into a triangle called gilouree, ready for chewing pleasure, as a stimulant or digestive, be it saada, meetha, with dry fruit or chocolate. The latest in the series is tandoori (paste) and some paans are ice-cream flavoured.

Betel-leaf mixture/paan masala, spiced/scented chewing tobacco/tambaku, gutka, mukhwas, scented areca/betel-nut/supari and other ingredients of betel-leaf/green paans can contain not only lime-paste/choona but other animal derived substances such as silver foil/varkh, musk/kasturi or some other animal origin fixative in the scents/bahar utilised. And if rose petal jam/gulkhand is used as an ingredient in paan it could contain honey, coral/praval pishti, pearl/moti pishti and varkh.

Betel quid: green paan leaf smeared with choona to which pieces of supari and other ingredients such as kattha and tobacco leaves are added. The paan is then wrapped into a gilouree, varkh could be applied, after which it is chewed.

Catechu/kattha: bark of a tree which imparts a red colour.

Chewing tobacco/khaini: tobacco and choona mixed in the palm of the hand. Ready-mixes (of snuff or snus) are flavoured and scented.

Gutka/gutkha: commercial preparation of supari, powdered tobacco, choona, kattha and other ingredients.

Mainpuri tobacco: mixture of supari, choona and tobacco to which some other ingredients may be added.

Mawa: mixture of supari pieces, tobacco and choona.

Mukhwas/variyali: consists of coloured, aromatic, sugar-coated (possibly covered with shellac) fennel/saunf /ajwain, sesame/til, coriander/dhania, pumpkin and other seeds, betel nut shivers and candied papaya, to which essential oils such as peppermint and rose have been added. It is sometimes used as one of the ingredients of meetha paan, which may have been smeared with choona.

Naswar: mixture of powdered tobacco, choona and indigo (plant).

Paan masala: commercial preparation of processed supari, betel leaf dust, choona, kattha and other ingredients such as menthol, except tobacco.

Qiwam is basically nicotine derived from tobacco, which gives the consumer a “kick”. Spices, herbs, saffron, menthol, incense (containing musk and amber), varkh, etc. are added.

Zarda: broken tobacco leaves boiled in water with choona and spices; then dried and coloured with vegetable dyes. Usually mixed with supari and spices and chewed.
Page last updated on 17/06/24