Why do we rinse tea leaf? | HOJO Online Speciality Tea Shop

We often rinse tea leaf before we brew it. Do you really know the reason for it?
Some people say it is because Chinese tea is often contaminated by pesticide and the rinsing is cleansing process to get rid of it. Of course it is not true. If pesticide is used, it is applied in late spring or summer when weather becomes warmer and pests become an issue. The farmer will not apply pesticide on freshly geminated leaf in spring. The pesticide applied in late spring or summer is absorbed by tea through its root and it stays inside the cell. Technically, there is no way to remove pesticide by rinsing even if it is really used. So what actually is the reason to rinse tea?

3 reasons for rinsing tea leaf

From my point of view, there are three reasons why we rinse tea.

1. To unfurl the tea leaf
2. Maintain high brewing temperature
3. For short time brewing

1. Open tea leaf

Some oolong teas, such as Taiwan oolong and Anxi oolong like Tie Guan Yin, are tightly rolled into ball shape. While Pu-erh tea is often compressed very hard into disc or brick shape. If we brew these teas without rinsing, water may not penetrate inside but only moisten the surface. This will result in very inconsistent brewing.

With rinsing once or twice, these teas will be loosen and unrolled. Usually, the better the quality, the faster the unrolling speed. We need to adjust the rinsing time according to the quality of tea.

2. Maintain high brewing temperature

The flavor and taste of fermented tea such as oolong and black tea are composed of substances like terpene and conjugated poly phenol. These substances are produced as a result of enzymatic oxidation. These substances have lesser affinity than poly phenol exists in non-fermented tea like green tea. Hence, it is important to get higher temperature to efficiently extract the substances when brewing fermented tea.

Many people would think that the temperature of boiling water is at 100 degree C. However, if we measure the actual temperature of hot water right after we stop heating, it is at about 95 degree C. Once it is poured into teapot, the hot water temperature drops about 10 degree C in summer and nearly 20 degree C in winter. In addition, dry tea leaf also contributes in cooling the water temperature to another 10 degree C. If no rinsing is carried out, you are actually brewing tea at 65 or 75 degree C. This is not hot enough at all to bring out the flavor and taste of fermented tea. Therefore, it is very important to warm up teapot with boiling water for 10 seconds, and again rinse tea leaf with boiling water for a few seconds. Usually, it is not very common to rinse black tea. However, some people rinse it if they practice Gong Fu brewing technique.

3. For short time brewing

The naturally farmed tea contains a lot of poly phenol or its oxide. Also as I mentioned above, the main taste component of fermented tea is also poly phenol oxide. In order to brewing these teas well, the key is how to extract these substances. Since these substances have lesser affinity with water, it is important to use water at higher temperature.

However, tea may be damaged if water temperature is too high. To minimize the damage, we ought to practice “high temperature and short time” brewing technique. It is said that high temperature and short time brewing gives lesser damage compared to lower temperature and long time brewing.
In order to achieve high temperature and short time brewing, we need some preparation. Firstly, warm up the teapot with boiling hot water for about 10 seconds. After pour in the tealeaf, rinse tealeaf once or twice swiftly, tealeaf will then unrolled and easier to extract its flavor and taste. Usually, after rinsing I put the lid back on and leave the tealeaf for about 10 seconds. The hot steam will remain inside the teapot. This steaming further helps tea leaf to be ready for subsequent brewing. With this method, we can get sufficient flavor and taste even if we keep entire brewing time in less than a few seconds. We can also practice the same technique for green or black tea. But the rinsing must be carried out as quickly as we can.