Tea flavour, health benefits reduced by rain

Researchers have found that shifting patterns of precipitation affect key chemicals responsible for the flavour and health properties of tea.

The research shows that major antioxidant compounds that determine tea health properties and flavour, including epigallocatechin, epigallocatechin gallate, epicatechin gallate, gallocatechin gallate, catechin and gallic acid, fell up to 50% in an area of Southwest China during an extreme monsoon, while other compounds increased. Household income from the sales of tea grown during the extreme monsoon also dropped by up to 50%.

The findings are based on samples taken from tea gardens in Southwest China. The researchers collected samples from two extreme weather events - an extreme drought and an extreme monsoon - and performed a chemical analysis of the samples. The researchers also interviewed tea farmers, who perceived the tea grown during the monsoon to be of lower quality and preferred tea grown outside of the monsoon season.

The findings were published in PLOS ONE, a peer-reviewed journal of the Public Library of Science.

The results of the research could have significant impacts on farmers' livelihoods, both in China and around the globe.

“Extrapolating findings from this study with climate scenarios suggests that tea farmers will face increased variability in their livelihoods with the increased prevalence and intensity of extreme droughts and heavy rains associated with climate change,” said lead researcher Selena Ahmed, assistant professor of health and human performance in the Montana State University College of Education, Health and Human Development. “The study has compelling implications not only for tea, but also for all other food and medicinal plants for which changes in weather patterns can alter flavour and nutritional and medicinal properties.”

Tea is a multibillion-dollar industry, with many consumers choosing to drink it in order to receive health benefits. Tea is the most widely consumed beverage in the world, second only to water, according to the University of Maryland Medical Center.

Green tea is recognised for its many health benefits that are attributed to powerful antioxidants called polyphenols, including the catechin compounds studied in this research.