Jaggery making is a cottage industry that provides livelihood to millions but, on the flip side, it has a negative environmental impact as the conventional manufacturing process involves open earth furnaces burning bagasse — a fuel with poor combustion characteristics. Some production units also use alternative fuels such as plastic or rubber waste, releasing harmful flue gases through chimneys. These practices can also reduce product quality, leading producers to use artificial additives to enhance appearance for market value.

Now, researchers led by Prof KS Reddy, at IIT-Madras’ Heat Transfer and Thermal Power Lab, have developed a solar-powered method for jaggery production that could transform this traditional sweetener’s environmental impact. With the use of sustainable energy, it addresses both the pollution and inefficiencies of current practices in jaggery production.

The system uses solar stills to produce jaggery from sugarcane juice. The approach combines refrigeration and solar heating, reducing energy requirements from nearly 100 MJ to 11 MJ per kg of jaggery produced.

Three-day process

On day 1, freshly harvested sugarcane is steamed to soften its outer shell. Extracted cane juice is then cooled to remove water in the form of ice.

On day 2, the juice undergoes secondary concentration in a series of solar stills. These stills utilise solar radiation and external reflectors to evaporate the remaining water content. The system can also operate without direct sunlight, using auxiliary heating methods.

On the final day, the concentrated juice is heated in batches to eliminate the remaining moisture, producing high-quality jaggery.

Valuable byproduct

The method generates distilled water as a valuable byproduct. The added revenue from distilled water production can reduce the payback period to less than five years. 

Under optimal conditions, the system produces 100 kg of jaggery and 169.78 kg of distilled water daily while reducing carbon dioxide emissions by 3,000 tonnes over its operational lifetime.

“Logistics, cost and awareness are critical,” says Reddy. “At the moment, we are working with internal teams in IIT to ensure that deployment on the field is effective.”

The system achieves nearly 50 per cent energy efficiency under solar conditions.

While still in the research phase, this approach demonstrates how traditional food production processes can be modernised to meet both environmental and economic demands. Its potential success could offer a model for integrating renewable energy into other food production systems.

(Yasaswini Sampathkumar is a writer based in Guwahati)