What Is Shellac? Sustainability, Pros, and Cons

Shellac is a natural resin secreted by the female lac insect (Kerria lacca), primarily found in the forests of India and Thailand. It has been used for centuries in various applications, including wood finishing, food glazing, pharmaceuticals, and beauty products. While priced for its glossy, biodegradable properties, its production raises environmental and ethical concerns, from deforestation to insect mortality. 

This article will explore how shellac is made, its diverse applications, and its environmental effects. We will evaluate whether this natural thermoplastic aligns with modern sustainability and cruelty-free standards. 

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What is Shellac?

Shellac is a natural resin secreted by the female lac bug (Kerria lacca), an insect native to the forests of India, Thailand, and other Southeast Asian regions. These tiny bugs feed on the sap of specific host trees, such as Butea monosperma (Dakha or Palas) and Schleichera oleosa (Kusum), and excrete a sticky, resinous substance that hardens into a protective coating on tree branches. 

This substance, known as sticklac, is harvested, refined, and processed into the versatile material we recognize as shellac. It contains acids, alkanes, and polyhydroxy polycarboxylic esters¹.

Shellac is a natural thermoplastic because it is soft, flows under pressure when heated, and becomes rigid at room temperature. Several industries see this resinous glaze as a good alternative to synthetic plastic. You will find shellac in various products, including sealing wax, nail polish, moisturizer, hair sprays, and varnishes.

The shellac industry imports mainly from Thailand and India, as both countries produce 1,700 tons of shellac yearly. Shellac production involves many stages, which start with workers collecting resin-covered twigs from host trees for further processing. The female lac beetle hosts include acacia, soapberry, and sacred fig trees.

The natural resin is non-toxic, food-safe, and can form a water-resistant, durable film when dried. These features enhance its application range, including food glazing, pharmaceuticals, and electrical insulation. Despite many of shellac's positive features, we must address the environmental impact and the ethical implications of the production of lac resin.

Shellac Production Processes

The production of shellac is a meticulous and time-consuming process that relies on traditional methods passed down through generations. While modern technology has improved efficiency, the core steps—harvesting, washing, melting, and refining—remain largely unchanged.

As demand for natural and biodegradable materials grows, sustainable practices in shellac production, such as ethical harvesting and reforestation, are becoming increasingly essential to ensure long-term viability.

Lac Cultivation and Harvesting

To get the resinous glaze most sought after by the shellac industry, swarms of lac bugs need to feed on some trees within their 6-month life cycle. Lac lifespan starts at birth and consists of eating, propagating, and producing shellac from the resin obtained from these trees. 

At specific periods throughout the year, lac bugs swarm trees and suck sap from the the bark and keeps sucking until ttey they feed themselves to death. As they feed themselves to death, propagation continues as the female lac beetle lays about 1,000 eggs before dying.  

The sap goes through a chemical process in lac bugs before being secreted onto the tree branch. Once the resin secreted comes in contact with air, it forms a hard shell covering the entire swarm on the tree. This process creates what we know as sticklac.

Production of Seedlac

The next stage of production is the refining of sticklac into seedlac. Plantation workers cut millions of encrusted branches to be transported into refineries, using mallets to break off the crusty coating at the refinery. 

Then, they scrape the sticklac to remove all secretions from branches and grind it with rotating millstones. This produces impure ground material that contains resin, insect remains, leaves, and twigs. To make it pure, the plantation workers force the ground mixture through a screen to remove the biggest dirt and impurities.

Next, the sifted resin is poured into large jars, where a worker stomps on it to crush it into granules further. The stomping removes the red dye from the lac seeds, and the insect remains in the resin. Then, they wash the dye water, dirt, and other impurities multiple times. 

The workers spread the mixture (often called seedlac) out on concrete to dry. Seedlac is the raw material manufacturers use to make orange and bleached shellac using modern or traditional shellac equipment (machinery or hand).

Heat and Solvent-based Refining Processes

The American shellac industry mostly uses modern, mechanical methods, including heat and chemical processes. 

With the heat processing method, the seedlac is melted onto steam-heated grids. It forms a molten lac forced through a sieve or screen of either cloth or fine mesh, by hydraulic pressure. The workers collect the filtered shellac and transfer it into a steam-heated kettle. 

The kettle drops the molten liquid onto rollers, which squeeze the liquid shellac into large, thin sheets. Once it's dry, they break it into flakes. The shellac flakes are then moved to another area, where they combine with denatured alcohol to produce the consumer's shellac.

However, the chemical process is quite different from the heat process. The chemical process uses a solvent, ethyl alcohol, to remove impurities from the seedlac. They mix seedlac and ethyl alcohol in a dissolving tank and then heat and cool it for an hour in a controlled process. 

Then, they filter the resin to remove the remaining dirt and impurities before sending it through evaporators. The evaporators help remove ethyl alcohol, turning it into a viscous liquid. Then, the rollers force the liquid into large sheets before turning them into flakes or grinding them into powder.

Bleaching

Manufacturers bleach shellac because of the red color of lac insects. Even after processing, Shellac has an orange hue, but producers bleach it by dissolving seedlac in an aqueous sodium carbonate solution. Then, they pass the mixture through a fine sieve to remove dirt, insoluble lac, twigs, and other impurities. 

They bleach the resin with a diluted sodium hypochlorite solution to get a white color, and add diluted sulfuric acid to the mix. Then, they wash and filter as normal before drying it in vacuum driers and grinding it into white powder⁵.

What is shellac used for?

Shellac has many applications in various industries, including pharmaceutical, confectionery, cosmetics, and electrical. 

Pharmaceutical producers use shellac to coat enteric pills so they dissolve in the lower intestine, not the stomach. They also use it on time-release medications.

The food industry uses shellac as a confectioner's glaze—a protective coating on candies because of its high gloss effect. The usual sweets that have it are jelly beans and candy corn. We also use it to coat fruits, other food items, and packaging. 

Furthermore, fashion designers use it to stiffen felt used to make hats. Shellac makes it easier for designers to shape the felt material into brims and bowl shapes. Shellac is also an ingredient lamp manufacturers use to glue the metal base to glass incandescent bulbs².

Producers use shellac wax in cosmetic and beauty products to replace Carnauba Wax and Candelilla Wax. The carpentry industry also uses shellac as wood polish, varnish, and sealant to make furniture more durable. 

Environmental Concerns Surrounding Shellac

We often consider shellac an environmentally friendly product because it is made from lac bugs; however, several environmental concerns exist regarding its production and use. One of the crucial ecological impacts of shellac is deforestation and habitat destruction. 

As you read when we discussed the production process of shellac flakes, workers cut down tree branches to access the lac bugs' resin secretion. Lac bugs depend on over 400 trees, which remain attached throughout their lifecycle. Pictured above is Dhak or Flame of the Forest (Butea monosperma), one of the host plants commonly found in South Asia³.

Overharvesting shellac can lead to deforestation and disrupt other wildlife ecosystems that rely on these trees. 

However, some believe there is a low percentage of shellac-induced deforestation because the trees that the lac bugs live in are on the IUCN list as Least Concern.

Another ethical concern is whether shellac can be considered vegan. It is not. According to People for the Ethical Treatment of Animals, around a hundred thousand bugs are sacrificed to make a pound of shellac flakes.

Some argue that shellac can be considered vegan and cruelty-free because producers do not intentionally harm lac insects. Despite being a natural form of resin, the base process of accessing destroys millions of lac bugs. Overharvesting could endanger or cause the extinction of these bugs. Furthermore, frequent harvesting is disrupting the food chain. 

Lac bugs are a crucial food source for moths, and they are also important to birds and pollinator plants. Disrupting the lac bug populations will affect the food chain and cause environmental damage⁴.

However, we argue that shellac is cruelty-free because lac bugs live for 6 months. Producers harvest them at the close of their lifecycle. Also, female lac bugs lay about 1,000 eggs just before they die to ensure the continuity of the species. You can already guess how they earned their title as pests. Overall, you can conclude that lac bugs are a renewable source of natural resin⁶.

Conclusion

Shellac has diverse applications—from shellac flakes in wood finishes to confectioner's glaze in food coatings. While its biodegradability makes it an eco-friendly choice, ethical concerns arise due to insect harvesting, prompting demand for cruelty-free alternatives. 

Shellac provides shine and durability in beauty products, yet vegan consumers often seek plant-based substitutes. Balancing sustainability and ethics is key to shellac's future. As industries evolve, responsible sourcing and innovation will determine whether this ancient resin remains preferred or is replaced by more ethical, synthetic options.