Art and Craft of Tea
Making tea is a true art. Every single batch is different and to create consistently high quality tea requires years of practice and intuitive “sense”. We know this because we’ve been involved in tea production firsthand. Complex chemical changes, in particular a process called oxidation, happen inside the leaves during each step of crafting process. Prolong or delay a few more seconds and the desired aroma is lost forever. Our partners’ expertise stretch through generations, and the journey starts long before we take our first sip. Here are some of the crafting steps involved in making tea.
During the harvest seasons, tea leaf is picked using hand (or machine in some cases) from the tea tree. This deceptionary “simple” step of plucking in fact entails significant skill.
First, temperature, humidity, and wind all affect when the leaf should be plucked from the tea tree to ensure optimum taste and aroma. For example, Oolong tea producers in China prefer to pluck when there is plenty of sunshine and low humidity, as these conditions aid subsequent withering and oxidation of the leaf at a constant rate that is controllable at the batch-level. Raining days are not suitable due to high humidity drastically alter withering rate of the leaf and the final taste.
A skilled tea plucker can employ both hands with much efficiency and speed without compromising the quality. With an ageing demography and shortage of workers, the number of experienced tea pluckers are in constant decline.
Withering is imperative in creating high-quality tea, and one of the key steps that creates colour, taste and aroma of a tea. As soon as the leaf is plucked, withering will start to occur while a freshly plucked leaf is being transported away from the tea field. At the simplest level, withering reduces the water content of the leaf under natural drying conditions. All teas undergo withering to some extend, and without this step it would be difficult for tea masters to create the beautiful shapes and tastes of tea.
A closer inspection also tells us that an important chemical step is happening within the leaf during this step - oxidation. Oxidation is an art that works like alchemy. Individual ingredients in the leaf go through a natural metabolic process, in the presence of air and enzymes within tea leaf, that transforms them into complex molecules that we recognise as a particular colour, taste and aroma in a tea.
Depending on the type of tea being processed, a tea master changes the level of oxidation the leaf undergoes by shortening or prolonging the withering process. For example, green tea is an unoxidised tea with minimal withering, and retain much of its original ingredients such as catechin, amino acids and chlorophyll untouched. Chlorophyll content gives green tea its green colour in the cup. Among its amino acids content, theanine takes up about half of the total, also known as L-γ-glutamylethylamide, and has an umami-like taste that is unique to high quality green tea.
Oolong tea is a partially oxidised tea with a wide range of oxidation levels created by each tea master who processes the leaf. Freshly plucked leaf is first left outside to wither in the sun, absorbing all the natural goodness of the light rays. Then, taken indoor to wither slowly to allow this time-intensive natural oxidation to take its course. This prolonged withering/oxidation step induces catechin and essential oils to transform into complex molecules that are responsible for a myriad of unique taste and aroma found only in Oolong. For example, molecules like nerolidol and methyl jasmonate are formed during withering step to give their characteristic woody/fresh bark and floral jasmine aromas respectively in some Oolong teas.
What about black tea? Black tea is a fully oxidised tea that is at the polar opposite to the non-oxidised green tea. Similar type of transformations happen in black tea, however, the aroma molecules formed are different (e.g. linalool and geraniol) to Oolong, and they exhibit more pronounced floral and fruity characters. Its dark colour in the cup comes from combination of orange coloured theaflavin, deep-reddish coloured thearubigin and brownish coloured complex catechin molecules - all formed during the oxidative withering step.
Bruising the leaf facilitates the breakdown of cell walls around the edges of the leaf, and induces further natural oxidisation of the leaf. Leaves are tenderised by being tossed on a bamboo tray. This process, unique to Oolong tea craft, is overseen by a tea master who fine-tunes the oxidation step in effect, and is repeated periodically whilst the leaf is withered indoor.
Application of heat to the leaf, in the form of steam, stops the oxidation by deactivating the enzymes within the leaf (polyphenol oxidase PPO enzyme). Steaming is a method used extensively to process non-oxidised green tea - widely seen in the making of green teas from Japan. Apart from steaming, there are three other types of heating processes - pan frying, roasting and sun-drying. All of these methods are used extensively in making green teas in China, and collectively they are called ShaQing | 杀青 in the traditional Chinese tea craft process.
Rolling is an important step that enhances the solubility of leaf’s natural ingredients in the cup. Hand rolling involves gently rubbing leaves together in a tea master’s palms (or wrapped in cotton cloth for balled Oolongs) and slowly squeezes the water content of leaf out without heat building up inside. This step serves three main purposes. First, it ensures the aqueous content of the whole tea batch is consistent throughout. Furthermore, the raptured leaf can readily release its precious ingredients in the cup, when mixed with water. When employed in the creation of oxidised Oolong and Black teas, this step also introduces oxygen in the air to the raptured leaf cells to enhance oxidation and hence its final taste.
Pan-frying is another way of heating the leaf to deactivate the enzymes. This method is widely used in creating Green and Oolong teas. Pan-frying the leaf subjects it to extremely high temperatures (250-300 C) in short period of time; lowering the leaf’s water content in a rapid rate and deactivate the enzyme instantaneously.
This step consolidates the already formed colour, taste and aroma of the leaf from the previous withering step. At the end of this step, leaf is mostly shaped into the finish product.
Slow roasting the leaf to dryness over charcoal enables tea leaf to be stably stored, and enjoyed over long period of time. Equally important, as an added benefit, roasting adds unique aroma to the tea itself. Skilled tea masters tailor the level of roasting to create desired roasting aroma. Patience is key as dehydrating the leaf too quickly leads to a poor tasting product.
The way of scenting green tea with jasmine flowers is said to date back around 1,000 years and traces its roots to Fujian, China. In the Qing dynasty, jasmine tea became reserved tea for the Emperor household retaining 150 years history of craft to this day. A top quality jasmine tea is created from a combination of suitable green tea and freshly opened jasmine flowers.
Ideal conditions for scenting are temperatures of 35-40 degrees celsius. Note that this relatively high temperature is normal during the summer months in southern China region, where jasmine flowers grow in the nature. Humidity is also suitably adjusted in the scenting room. Excess humidity causes delay in “transfer” of jasmine aroma to green tea base, while low humidity causes jasmine to wilt too quickly. Sufficient oxygen level should also be maintained through good ventilation to make sure jasmine breathe properly and continuously release scent.
The final step of the process involves sorting leaf into groups of equal grade to ensure consistency of the batch. Skilled workers visually inspect each pile of leaf to remove any undesired storks.
Fermentation process in tea uses naturally present bacteria in leaf to ferment the tea. Note that this secondary process is different to the oxidation step involving enzymes in the leaf. In the processing of Puerh tea, the unrefined green tea (Maocha) containing natural bacteria slowly ferment over time to give dark earthy flavours.
CTC (Crush Tear and Curl)
CTC (Crush, tear and curl) is a mechanised way of processing black tea invented around 1930. The machine mimics the orthodox hand processing of traditional black tea described above, and is heavily in use in large industrial scale tea plantations in India, Kenya etc. The primary advantages of CTC processing are in the ease of operation and continuous run. However, the lack of human intervention during each step means that the quality of CTC tea can never reach the level of orthodox black tea. CTC became the catalyst for the commoditisation of tea since these small broken and often dusty teas were only suitable for tea bags.