“Thach co tra”, which is a black tea block with a diameter of 40 cm and weighing around 16kg, is a combination of six different types of tea including green tea, yellow tea, white tea, Oolong tea, red tea, and black tea.

The name "Thach co tra" signifies tea grown on rocks, or can be referred to as rocked drum tea based on Han (Han Chinese script) and Nom characters.
It is inspired by the ancient indigenous tea trees in the sourcing area of this product variety in Tung San Commune, Hoang Su Phi District, Ha Giang Province.

This area is located at an altitude of 1200m - 1800m between the Tay Con Linh and Chieu Lau Thi mountain ranges, with temperatures often below 5 degrees Celsius compared to the surrounding regions.
Here, there exist many ancient tea trees with life spans ranging from 400 to 1,000 years, with their roots deeply entrenched in rocky crevices.

The block is crafted using a combination of traditional and modern methods, drawing inspiration from the ancient Pho Nhi technique originating from China and the Oolong tea-making methods from Taiwan (China).
Nguyen Dang Ben, General Director of IGV JSC, said that to preserve the sourcing area, they would only harvest the tea leaves in two sessions, spring and autumn.

“The optimal time to harvest young buds is typically around two weeks after the start of autumn leaf picking, which helps ensure the highest quality and a balanced blend of nutrients and flavour,” Ben said.
The harvesting method of tea is a significant concern as it aids in preserving the health of the tea plant and ensuring the quality of the harvested leaves, according to Ben.

Raw tea leaves are harvested using the "one bud, two leaves" technique, wherein two young leaves along with the bud are plucked from the branches of the tea plant, while one leaf is left behind to allow the plant to continue growing and producing new leaves.

Freshly harvested tea leaves will be withered for half a day. If it is raining or the air humidity is high at that time, the withering time will be extended.
During withering, the tea will be manually stirred every 30 minutes to prevent moisture from being retained in the leaves, thereby avoiding the tea from becoming sour. The heat from the hands helps enhance the flavour of the tea.

After that, the tea leaves undergo a rolling and compressing process into a block, followed by drying and slow roasting. Each block consists of multiple layers of tea leaves, with each layer undergoing a unique degree of fermentation. The entire process takes around 3,000 hours to complete.
He said that producing a 16kg tea block requires up to 100kg of rare tea leaves and the production quantity is limited to around 20 tea blocks per year.

“This type of tea was only commercialised two years ago, and it's been purchased not only for consumption but also for collecting and investing purposes. The tea blocks increase in value over time, with an appreciation rate ranging from 15 per cent to 20 per cent per year,"
He said “The tea will be supported for preservation for 10 years, and afterwards, we offer cold storage services that can extend preservation for up to 100 years.”

Ben said the idea for this type of tea originated from the event "Hundred-year Tribute Tea Returns Home, Good Expectations for Pu'er," which took place on March 19, 2007, in Xuanwu District, Beijing, China./.