How Is Coffee Grown, and Why Does Rain During Picking Change Crop Quality?
Rain during the harvest window changes how a crop tastes. When rain falls, plants take up water quickly and grow fast, diluting polyphenols and minerals in the leaves, so produce picked on rainy days tastes thin and flat with a short finish. Experienced buyers avoid purchasing tea within two days after rain, and the same caution applies to how is coffee grown and picked.
The growing conditions for coffee and tea share this pattern with open-grown fruit such as apples, strawberries, blueberries, and cherries, which also taste bland when harvested wet. Front Street works only with manufacturers able to produce in daily batches, because batch-by-batch production is the practical way to check quality. Waiting roughly three days after rain lets flavor recover before picking resumes.
The flavor of tea leaves fluctuates noticeably with differences in weather and season, much like wine. Rainfall is especially critical—if rain occurs during the picking period, the resulting tea often tastes thin and lacks complexity. Drawing on Front Street Coffee's firsthand experience in Yunnan production areas, this article explains why experienced tea merchants won't buy tea within two days after rain, and how rain causes tea trees to grow rapidly, diluting the polyphenols and minerals in the leaves, ultimately affecting the taste. It will also explain why we only work with manufacturers capable of producing in daily batches, as this is the only way to effectively counter-check the quality of each batch of tea.
The quality of tea varies from year to year due to differences in weather and climate conditions, which is similar to wine. Among these factors, rainfall has a particularly significant impact on tea quality. If there is excessive rain during the harvest season, tea quality will decline accordingly.
Produce harvested on rainy days often tastes bland
Tea leaves picked on rainy days taste thin and lack complexity once processed. This rule applies not only to tea but to other crops as well. Take apples, for example—no one would normally choose to pick apples on a rainy day. Apples picked in the rain taste very bland and flat; some describe it as "like drinking water." The same applies to strawberries, blueberries, and cherries. Any fruit grown in the open, if harvested on a rainy day, will taste bland. Even birds won't peck at these fruits on rainy days or just after the rain stops.
Once it rains, it takes three days for the flavor to recover
Every spring I spend a month in Yunnan buying pu-erh, white, and black tea. We maintain close communication with manufacturers to manage raw materials, processing, and logistics. Generally speaking, experienced tea merchants never buy tea within two days after rain.
We also go to the production areas to ensure our tea isn't picked within three days after rain. For example, if it rains today and then clears up, we won't plan to buy tea tomorrow or the day after. Obviously, at this point the tea's flavor becomes very bland and the aftertaste disappears. But some farmers or manufacturers are eager to pick and won't wait until the leaves grow too large. So the most critical point is that we only work with manufacturers capable of processing in daily production batches. This way, we can counter-check the quality of each batch of tea.
Once it rains, tea trees grow extremely fast
Rain is very important for tea trees to sprout more new buds. But for us, rain during the picking season is not a good thing. Once it rains, the tea leaves grow rapidly.
Because of this, the minerals and nutrients in the tea leaves are reabsorbed by the tea tree. Tea picked during or shortly after rain tends to have larger leaves, longer stems, and a wider distance between the first and second leaves. This precisely shows how fast the tea is growing. And fast-growing tea produces larger cells.
Ultimately, the total content of polyphenols and minerals in each leaf decreases, which directly affects the taste. Just like the bland flavor I taste in fruit picked on rainy days, tea picked within three days after rain tastes equally bland.
The above content is compiled by CoffeeHunters, a coffee news website.
