New Delhi, April 10 -- Jesuit priests arrived in South 24 Parganas in West Bengal in the late 19th century. In the Sunderbans, they built schools and dispensaries, and carried out relief and missionary work across the remote islands, gradually making it their home. During summer, the extreme humidity made them rely on a concoction of coconut water, taal michri, a sweetener made from the sap of Palmyra palm, honey and ginger stored in earthen pots, to stay hydrated.

"Over many trips to the Sunderbans, we discovered summer in these parts often made drinking water unsafe. It was also the time of the cholera pandemic in Bengal back then," says Santiniketan-based culinary researcher and chef Amrita Bhattacharya. She points out the drink serve...