Camellia sinensis, like any plant, has it’s own personal set of preferences as to where it will happily grow. It likes an acidic, well drained soil and needs at least 50 inches of rain a year to flourish. It also needs a long day length, which limits the distance from the equator that it can be grown. Within these basic requirements there are still a lot of variables to be considered, and many people insist that these make all of the difference to the finished tea.
Altitude is one factor which especially has to be taken into account, with many claiming that the further above sea level the plantation is located the better the quality of the finished tea. A study has shown that the content of some flavour compounds and caffeine increase with the altitude at which the tea is grown while other flavour compounds decrease as the plantation rises, so altitude definitely effects flavour. Tasters who evaluated the teas sampled in the experiment did give higher ratings to the higher grown crops so it seems that high altitude really is something you should look for in your tea.
Micro climate is also very important and the variations in weather that each plantation experiences can make all the difference. It isn’t just the levels of rainfall that are important but the way it falls. More than one rainy season is beneficial, and the time of year at which the rain falls is critical. A study carried out in the Assam valley showed that the timing of the rainy seasons and the corresponding temperatures combined to significantly effect yields throughout the year.
Annual temperatures needs to stay within a 13-32º C range for tea plants to maintain optimum growth. There has been some anecdotal evidence that increases in temperature at Indian plantations has led to a more bitter taste in the final product, but this has yet to be investigated scientifically.
With climatic factors playing such an important part in tea production, it’s no surprise that climate issues are big concerns for a lot of producers. It is difficult to predict the exact effects that global climate will have on specific areas, but it is certain that climatic zones are shifting. With the best tea coming from plantations that have taken decades to become established, replanting won’t be a simple matter if the boundaries shift too far.
Owuor, P., Obaga, S., Othieno, C. (1990) – The effect of altitude on the chemical composition of black tea. Journal of the Science of Food and Agriculture 50(1) 9-17
Sen, A., Biswas, A., Sanyal, D. (1966) – The influence of climatic factors on the yield of tea in the Assam valley. Journal of Applied Meteorology 5(6) 789- 800
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