Dim sum culture goes back a long way in the southern Canton area, a healthy, balanced and yet delicious breakfast with a rich array of food selections and ingredients and pairing with a fine choice of tea as well. It is considered a healthy habit to hydrate oneself with a daily dose of fluid and caffeine in the morning with a yummy dim sum to start the day and socialize with friends and colleagues in a meeting of minds.
Tea merchants who prepare tea for these dim sum restaurants must meet specific requirements like the tea must have good transparent red colour, taste, reasonable priced and multiple steeping to last an hour-long breakfast. As a result, cellar storage was invented and developed to satisfy the need to provide tea for these restaurants. The humidity and temperature of these cellars are relatively constant outside; it's cooler in summer and warmer in winter months. In the beginning, only loose Pu-erh tea for dim sum restaurants was stored in these cellars and in many cases, water was added to the tea to increase the temperature and humidity of the cellar. The effect is similar to the piling process in Yunnan, where adding water to tea in large quantity will create heat and fermentation. The temperature in summer can get up to 50 to 60°c when the cellar is full of tea.
The size of these cellars range anywhere from 70 to 120 M² and usually lack windows for ventilation. It is only a later development that teacakes and other Pu-erh products were stored in these cellars. These products must be closely watched as prolonged high heat can damage the packaging paper and the young sensitive tip on the surface of teacakes. There are also cellars for the storage of teacakes only where the temperature is not as high. All bales stored in these cellars must be rotated from top to bottom yearly as the temperature and humidity can vary, and rotating the stock can achieve a more unified result; it is usually carried out in winter months when the workers do not have to sweat as much. We remember as a kid growing up around the tea shop, my father will request us to go to the cellar and take out specific sample for testing, for a small reward, of course. All the test results are recorded and labelled.
A Typical Cellar Warehouse stacked high with various products.
Cellar storage is a unique phenomenon in Hong Kong during the early 20th century because of the hilly geographical condition where buildings are erected on hillsides, creating the basement underneath most buildings. As the urbanization process taking place over the past few decades, many of these cellars disappeared to make way for new and modernized facilities. Large scale tea warehouse moved to more organized and manageable industrial buildings where temperature and humidity are often created artificially to provide the ideal atmosphere for the post-fermentation of tea.
High-rise Professional Warehouse
The followings are a few general rules of Pu-erh tea storage base on many years of experience of Pu-erh tea storage from a professional and commercial point of view.
High humidity must work together with high temperature. If only humidity is high in a dark environment, white mould will easily be formed and gives teacake a dull grey appearance.
Gentle and mild-tasting tea, like many Yi Wu tea, is not suitable for cellar storage. Since the young spring tip is very sensitive to excessive heat and moisture, high temperature and humidity storage are suitable only for board leave tea with high astringency and cha qi.
Stronger or high-value tea like the hundred years old wild-grown tea can consider storing in the cellar for a limited period of 2 to 3 years, then change to room temperature storage. This process will yield a smoother tea character and enhance the taste and increase the steeping number. This category of teacake is usually costly and made for tea appreciation. Anything longer than 2 to 3 years in a cellar is not advisable since prolonged storage to high heat and humidity will affect the original character and complexity of the tea itself.
It's hard work! All bales stored in these cellars must be rotated from top to bottom yearly.
Pu-erh tea has the natural tendency to absorb and release its fragrance, especially at a temperature above 30°c. On the contrary, if the temperature is below 25°c, it emits very little fragrance. If different Pu-erh products are stored together in a cellar situation, the fragrance will affect and absorb each other. Prolong period of 10 to 15 years under these conditions may become irreversible, and the tea products will bear a taste or flavour foreign to their true taste. We refer to this common fragrance as warehouse odour as most of the products will rarely store in a cellar warehouse for longer than ten years, except for ripe Pu-erh. Most products will move to room temperature warehouse in under ten years. We see this warehouse odour as desirable and positive as these cellars or industrial building warehouse takes many years to create this odour because its only purpose is to store tea only. Sometimes we come across products with an earthy aroma from other warehouses; for obvious reasons, the place is either too new or not prepare properly for tea storage.
The optimum timing and temperature of aging Pu-erh tea and a successful post-fermentation process requires a good understanding of the natural characteristics of the tea itself. Time, temperature and humidity are probably the three most important factors. One can draw an imaginary line with one side of it storing tea at a temperature below 25°c, the tea store under this temperature is on a natural preservation stage, and aging at natural speed without altering the living tissues and the true taste of the tea itself and releases very little fragrance and temperature during the process. On the other side, for prolong storage of temperature over 30°c, this process is similar to the slow cooking of food, time takes its toll, and as mentioned earlier, the constant release of fragrance and temperature of the tea is a sign that the tea is slowly ripening. This process is irreversible and speeds up the maturity process, at the same time, some original taste and fragrance may also permanently lost. When we look at some very outstanding aged tea products in the market today, like the 1920's Song Pin Hao Round Teacake of the Antique Era or some 1950's Red Mark from the Masterpiece Era. Their value lies in the complex and ever-changing taste evolved throughout its existence and preserved throughout the years.
A well ventilated industrial professional warehouse
The fact that raw Pu-erh tea is a living plant so in the storage or post-fermentation environment, it is just logical to provide enough air circulation for tea to continue its living process, just like a living plant in nature going through the natural changes of weather and seasons. There is some practice of aging tea in totally enclosed and airtight condition to maintain the temperature and humidity. That storage method will, in many cases, make tea dull and grey or even overheated, which will severely affect the taste, and the processed tea leaves will feel rigid and dark.
In the situation when collectors want to store tea at home, a small container of water in the summer months will help to balance the humidity, especially areas with humidity well below 78%(average yearly humidity of Hong Kong)
As the debate over cellar storage versus dry storage intensified. Being close to 5 decades in the business as the Pu-erh market bloom to the size it is now, we think the Pu-erh tea has lost some of its original meaning of being a humble, smooth, neutral and easy-drinking tea of an ethnic Southern Chinese tea to a very sophisticated highly valued tea for appreciation. Of course, we welcome these changes as we think Pu-erh tea should always be affordable as an everyday drinking tea. At the same time, the recent development of scarce, handcrafted thousand-year-old arbor tree from a single individual tree is created mainly for taste appreciation. We are noticing a shift in the tea from being the maintenance of good health and good for digestion to a more taste orientated drink.
Historically, since the Qing Dynasty, the privately run tea merchants were always selecting their material from wild-grown trees thus earned their fame of tribute tea good for the Emperors. The Cultural Revolution has increased tea production due to the use of highly efficient plantation agriculture and State-run factory. And by the turn of the 21st century, the Pu-erh market has opened up to the existence of many new tea factories. The good news is the emphasis is back to making quality Pu-erh tea products again. In the meantime. Tea appreciation has been going on for many years, and those tea are kept at normal room temperature. Tea appreciation really became popular during the 1970s and 80's when Pu-erh tea production in Yunnan increased and became affordable to many people from all over the world. Also, the making of teacake became more commercial and many choices and price range are available. Some good quality and well preserves loose raw or ripe tea are always a bargain.
There are certain pros and cons about cellar storage as they must be closely watched by experienced professional people. Since it may take anywhere from 10 to 30 years in the course of post fermenting a good quality Pu-erh product, It's advisable to get it right from the start because it takes a tremendous time and effort to do so. Most ripe or everyday drinking Pu-erh products are best for cellar storage because they enhance the smoothness, taste and steeping number of the tea. The shortening of the post-fermentation process can lower the cost and the taste is just right for normal everyday drinking. For people who like to collect tea for investment, good quality wild-grown hand finish products from the well-known factory may be a smart choice. Since all Pu-erh products vary in their ingredients, it's a general rule that most products with young spring ingredient are sensitive to high heat and moisture, and the tip will turn dull silver if not handled carefully. On the other hand, wild-grown board leave products can tolerate cellar storage for around 3 years then change to room temperature storage or professional control warehouse for the rest of the post-fermentation process.