Tender coconut water (TCW) is rich in nutrients, presenting low fat levels, and considered to be an excellent isotonic drink. To understand the chemistry of TCW, samples of TCW with 6–7 and 11–12 months of maturity were collected from the same coconut trees in different locations in the coastal Cuddalore district. It was found that TCW is dominated by K+ among cations and by Cl- among anions. The pH of the TCW was acidic to neutral, with high electrical conductivity. Comparison of the TCW samples with drinking water standards show that the former contained certain ions more than the permissible limit. It was understood that the process of selective absorption by plants or by certain other chemical process taking place during the formation o...