Living in Berkeley California exposes you to enthusiasts of all types; we have yoga gurus, herbal devotees and wine connoisseurs galore. At a party last week, a man from Georgia wearing wool knit socks as shoes and Mexican beaded jewelry showed up with a suit case filled with tea. He was a tea obsessive, which honestly I’ve never run into this side of the pond. Did we want an herbal infusion with spearmint and marshmallow (the plant, not the gooey treat)? Would we consider a pu’erh tea that smelled like toes and tasted like mushrooms? This one is magical, ingredients secret…would we consider a second cup? Having had a rather rebellious youth, I had learned early on not to take tea (or other unknown substances) from strangers, or at least know what to expect. A hilarious bike ride home and a sleepless night for my fiancé (who enjoyed three cups), led me to believe I was correct in sticking to water. However the whole incident made me think about the tea drinkers of the world. What is it about tea that makes them so fanatical and where will they be in 50 years as tea flavors change with climate change?
At first look, it would seem that tea, like all plants, would do well in a warmer environment with more carbon dioxide (ie what is predicted with climate change). Don’t plants use carbon dioxide for photosynthesis? Doesn’t more photosynthesis equal more plant growth? Wouldn’t higher temperatures equal a longer growing season? Wouldn’t that be more time for any plant to grow and prosper?
From this perspective, climate change rocks. But think for a minute about apples, which require cold snaps to flower, being trapped in regions with progressively warmer winters. Or strawberries, that are overcome by mold in hotter, wetter summers. Plants are fickle, they are not all about unencumbered growth, and tea plants are no different.
Growing in tropical and subtropical climates, tea is an ideal hillside crop, with lovely tea being plucked from high elevations. Loving warm, wet environments, tea has been prospering in these regions for thousands of years. As a result, if you change the climate, you will no doubt change the availability of tea. For countries that are dependent on tea for their economic prosperity like Sri Lanka, lower tea growing regions are expected to see changes in rain and temperature (1). Changes in climate in these areas equate to a lower yield. For a region that has just come out of a 25 year civil war, an economic downturn in one of its largest exports would be devastating.
However with tea, like wine, cheese and chocolate, it’s not about how much you can drink, it’s about how it tastes. Similar to wine, the climate of the region where you grow your tea can change its terroir (flavors developed by the regional characteristics of where it was grown). And this is where tea could really be in trouble.
Tea depends on a couple of compounds to give it its delightful flavor. These compounds vary throughout the season, and are impacted by the environment (2). One of these groups of compounds, polyphenolics, are carbon-dominated molecules that are responsible for a range of activities in plants, from defense against insects to protection from sun exposure. In tea they are known for giving the drink its astringent flavor, its deep color and some of its positive health effects. Based on research that has found that these compounds change with temperature and rainfall in other plants from red maple trees (3) to tomato leaves (4), it wouldn’t be hard to guess that they would change in tea leaves too (NSF grant anyone?).
Tea is a large enough industry for the Journal of Food Chemistry to devote a special issue this coming year to tea and only tea: tea quality, tea flavors, tea nutrition and, most importantly, environmental influences on tea sensory properties (that means how climate effects flavor) (5). So tea drinkers, enthusiasts, lovers and obsessives, what about the future of tea? How important is terroir to your tea drinking experience? Will tea prices inflate as a changing climate moves tea plantations up the mountainside? Moreover, what will happen when the price of tea in China will be more than a suitcase wielding hippie in Berkeley can bear?
Minda has a PhD in Biology from Tufts University and is a science blogger in the Bay area. She enjoys her tea at Far Leaves Tea on San Pablo, where a pot of Pu’erh Gold and a sesame bun will set her back $8 and 3 hours in quiet contemplation. This is California after all.
Further reading for your enjoyment:
1Assessment of impact of climate change on productivity of tea (Camellia sinensis L.) plantations in Sri Lanka
2 Seasonal variation of total phenolic, antioxidant activity And minerals in fresh tea shoots (camellia sinensis Var. Sinensis)
3 Changes in the structural composition and reactivity of Acer rubrum leaf litter tannins exposed to warming and altered precipitation: climatic stress-induced tannins are more reactive
4Resistance to cold and heat stress: accumulation of phenolic
compounds in tomato and watermelon plants
5 Special issue of Food Research International on Tea – from bushes to mugs: composition, stability and health aspects