One of the things we love about working with traditional tea farms is that the growers we work with are primarily concerned with how the tea tastes, rather than how much they can produce. With this focus on quality over quantity, we are free to appreciate the ways in which even subtle differences in growing conditions can dramatically change the final flavor in our cup. By tasting several lots of tea from the same farm or season, it is easier to isolate specific variables like changes in weather patterns between different farms or years, or even between specific weeks during the harvest season.

Differences in weather between seasons are one of the most important factors in the overall grade of the finished tea, and often correlate to levels of bitterness or astringency as the plant grows more mature leaves throughout the annual growth process. Differences in regional weather patterns, along with local flavor preferences and crafting styles, define ideal harvest dates for each type of traditional tea. And variations in weather patterns, whether from year to year or week to week, keep growers, crafters and tasters on their toes, ensuring that no two harvests taste exactly the same.

Seasonal Weather Patterns

Though teas are grown all over the world, the annual pattern of growth recognized by traditional Chinese farmers can be applied to any temperate tea growing climate. In the spring, the tea plant puts out new shoots using nutrients saved and stored through the winter to produce new growth and take advantage of the longer daytime hours. Leaves picked during this season are typically considered the best of the year, especially for green and white teas, since the minimal crafting methods used for these styles have less impact on the final flavor. We often compare spring harvest leaves to baby spinach or arugula, which is naturally sweet because it is harvested before it has fully matured.

In the summer, the tea plant can grow many new leaves rapidly, and as it converts sunlight into natural sugars, it sends any excess to the roots to build reserves for the coming winter. The maturing leaves are left with little natural sweetness, but are larger and more plentiful than during the slow growth of spring. Many mass produced teas are picked during the summer, when larger batches can be harvested more quickly, but often display bitter or astringent flavors due to the plant’s production of tannins during this time.

In the fall, as the weather cools, the tea plant must struggle to produce new growth again, and the slower process causes some additional flavor complexity to develop in the leaves. Some oolongs are picked during this season, but many tea farms are winding down for the year. Once the temperature is cold enough, the plant will enter a season of dormancy for the winter, during which it will produce no new leaves but focus on storing and processing nutrients in the root system to prepare for spring.

Regional Weather Patterns

In tropical climates, however, temperatures never get low enough to induce dormancy, and the tea plants miss the opportunity for development of complex flavor compounds as they constantly strive for maximum growth. Though there are other differences between the two styles, this is one of the major distinctions between lowland Assam teas and highland Darjeeling teas grown in India. Darjeeling has historically been highly prized for more delicate, complex flavors simply because the region’s elevation allows for this dormant winter period.

The annual pattern of rainfall in each region can cause a similar differentiation in tropical climates, however, with monsoon season bringing speedy growth that reduces flavor complexity, especially in lowland teas. Though tea plants require a relatively wet climate for optimal growth, too much rain will “wash out” the flavor by encouraging faster growth and preventing flavor from forming with the development of secondary metabolites.

Annual Variation

Even given the same harvest date and provenance, the flavor of any given tea is likely to vary from year to year based on differences in annual weather patterns. In a wet year, teas may taste lighter but be more plentiful, while a drought can negatively impact production quantities but intensify flavor by slowing growth. As with the effects of harvest date, these effects are most obvious in lightly oxidized teas, where minimal crafting leaves nowhere for flaws to hide.

The unpredictable weather patterns that come with climate change are therefore dangerous to a tea farmer’s bottom line, since a single early rain or poorly timed cold spell can dramatically impact the quality or quantity of a harvest that only comes once a year. The most vulnerable operations are those in low-lying tropical areas, where heavier rains and hotter summer days threaten the delicate root systems of fast growing, fertilized plants, and negatively impact flavor quality. High elevation tea farms with diverse growth and natural growing methods are more prepared to sustain production of high quality tea, as excess rainwater quickly runs off and temperatures are generally cooler.

Ultimately, it is up to the skills and expertise of the farmers and crafters to judge the perfect time for harvest and the perfect method of crafting the leaves to bring out the best side of every tea. As buyers, all we can do is accept each new year’s harvest as a new tea experience and appreciate it for the fleeting moment that it is, since next year’s crop will always be different.

Do you appreciate variations in flavor each year? Let us know in the comments below!

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