Most teas are named after colors. Even oolong tea (Chinese: 乌龙, which doesn’t mean anything in English) has the color “black/dark” in its native language.
Of course, the color of tea leaves doesn’t necessarily have to correspond to its name. For example, some premium black teas have golden leaves. (This is why black tea’s original name in Chinese makes more sense. In China, black tea is actually called “red tea/红茶”, and it’s named after the color of tea soup instead of dry tea leaves.)
Nonetheless, when we open a bag of any tea, unless it’s blended with spices or flowers, tea leaves should have the same color.
Oolong tea lovers, however, are often puzzled by the color of tea leaves. Every now and then, we get questions from our Instagram followers asking why some of their oolong teas have a few yellowish leaves. Today, let’s thoroughly explain the “presence” of “yellow leaves” in oolong.
One thing we must emphasize first: yellow leaves are not normal. More yellow leaves, lower the quality.
When dry, these yellow leaves have a color of dried olives. More specifically, they have a yellowish green color.
Yellow leaves are old leaves. Most fresh oolong leaves are harvested with the top one bud and three/four leaves. If the harvest is sloppy, the fifth or even the sixth leaves would be taken down as well, and eventually they become yellow leaves.
The broader and harder fifth/sixth leaves usually have a wax layer. If you feel these leaves, the wax layer has a distinct smooth touch. The wax layer is a natural “protective and waterproof film”. With this layer of wax, pigments cannot be easily oxidized. Therefore, these “elder” leaves can maintain its original yellowish green color.
Furthermore, if the harvest is late due to mismanagement or bad tea-making decisions, the third or the forth leaf can also develop this wax layer.
In tea-making, the color of normal fresh leaves is first transformed into a brownish olive green (before the roast), then into a dark charcoal color (after the roast). Older leaves, though, have the protection of the wax layer, and most of them carry their original color all the way through.
Mixed together, yellow leaves become quite obvious to human eyes.
There’s one main reason for yellow oolong leaves: incomplete or flawed sorting and selecting process. This is why yellow leaves are more common in low quality oolong teas.
Normally, either human or machine harvest can completely avoid harvesting some older (yellow) leaves. It’s acceptable if a serving of oolong tea (7g-8g) has one or two yellow leaves. But it’s definitely not permissible beyond this number. If a oolong tea is with half or even 2/3 yellow leaves, it’s undoubtably a bad product.
Traditionally, tea sorting and selecting process involves a lot labor work. Tea workers’ experience and proficiency are the key to the elimination of yellow leaves. Interestingly, most sorting and selecting process is performed by women. Experience shows women are much better at distinguishing colors.
Modern technology allows tea makers like us to use spectrum sorting machines. This greatly shortens the time and the cost of sorting and selecting. Nowadays, we can process the same amount in hours that used to take us days.
Yellow leaves in oolong tea is anything but a good sign. One or two yellow leaves are okay, but a majority of yellow leaves in tea could disrupt the flavor and the aroma. We hope this blog can help you better understand the yellow leaves in oolong.
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