The Craft of Tea Processing
Centuries before the term “processed food” would become a euphemism for junk food, tea producing communities were developing the processes and tools that transform raw leaves into aromatic dry tea. The task of processing tea is not simple or intuitive, and there isn’t really a one size fits all set of procedures used in all cases. In the run-up to the opium war the British tried and failed for years to reverse engineer tea processing with the native assamica tea plants in India. It took Robert Fortune, botanist-turned-spy, sent illegally into China on a mission to see tea processing firsthand before they even knew black and green tea come from the same plant.
A century and a half later tea processing isn’t a Chinese state secret, but the processes used by the highest quality artisans emerge from the unique environment their tea is made in. There are geographic factors like weather, economic factors like labor availability, technological factors in the degree of industrialization, and cultural factors like the intergenerational knowledge of how to craft tea their way. This confluence of factors have helped prevent tea from becoming an entirely homogenized and industrialized processed food product (despite attempts to do so).
Harvesting At The Right Time
Harvesting and plucking are the real first step to tea processing. Getting this part right isn’t as simple as it might seem at first. The plants need to be ready with the bud fully opened and the fresh young leaves at the desired ripeness. The time of year a harvest begins depends on the specific microclimate of the farm and the weather patterns at that time. Higher elevation tea farms directly above lower elevation farms on the same mountain will begin harvesting later in the year. Rain in the spring is important, but too much rain at the preferred time to harvest tea can cause delays that can ultimately hurt the quality of the harvest. Smaller farms that rely on the sun in the withering process can be hampered by even a cloudy day. On the other end of the spectrum there are climates that allow for a year round harvest schedule such as Nilgiri India, Sri Lanka, and Southern Africa.
Picking – Balancing Precision and Efficiency
Despite the existence of tea harvesting machines, hand picking is still practised widely across the world. Craft tea producers who have specific standards for their tea recipe will specify how far down the stem should be picked. Its common in India to pick two leaves down from the bud, and in Taiwan for the stem to remain intact through processing with three or four leaves included. Tea makers need to have this level of control over the grade in the recipe if they want to produce their desired tea. It’s not the case that tea with a higher percentage of buds is better or worse on that basis alone, but the resulting tea will change as a result. Skilled tea producers who knows her desired tea and the plants she works with also rely on the precision of tea pickers.
Once you have a morning’s harvest of fresh picked tea leaves they need to lose much of their water content before applying heat or rolling. Tea leaves fit for processing are soft but still firm and full of water and intact cell walls. Withering is a several hours long process in which tea leaves are laid out on mats and allowed to wither, or wilt as they lose about half their water content. The volatile aromatic chemicals in tea leaves are now much more accessible and the tea leaves themselves are soft and pliable. The naturally occurring oxidation of tea leaves can now be kickstarted by the tea maker for the desired style of tea. Withering can be as simple as being left out on the roof of the farmhouse or it can take place in special rooms with temperature and humidity controls. The ultimate goal it to take a big bite out of the moisture in the leaves.
Once you have soft withered leaves precisely how you want them, tea needs to undergo a heating process seal in the aroma and flavor of tea. Sometimes this step is called fixing, steaming, frying, or kill-green. This heating process removes more of the water content and halts oxidation. Heating tea without scorching it is not an easy task, in China handmade tea is made in big woks while someone manually tosses the leaves. This is a stage where the experience and intuition of the tea maker comes into play as changes in temperature or extra time spent at the wok tossing the leaves can drastically change the final tea. Japanese tea uses a more industrialized steaming process that has a dramatic effect on the final flavor of the tea.
Rolling, Oxidizing, Bruising
For some styles of tea this process can take place before the heating phase. Pliable tea is traditionally rolled into shape by hand on bamboo mats but even small-time producers make use of rolling machines that break down the cell walls further, release oils, and help twist the leaves into the common long shape of loose tea. For some teas this stage is all about “bruising” the leaves for a specialized oxidation. Oolong teas can undergo a cyclical process in this phase where they are heated, rolled, compressed, and the process is repeated until the tea is determined to have the desired shape and flavor.
Tea will need to undergo a last controlled drying phase to drive out the remaining moisture. Black teas do not undergo the same kind of heating phase so they need to undergo a well calibrated roasting at this point not only to remove the water but to bring out the best flavor. Oolong teas have similar needs at this phase and specialized heat sources like charcoal are used to transform buttery floral high mountain oolong into a complex roasted Tieguanyin.
This is the basic outline of tea processing. There are more steps like pile fermenting and pressing for puer, bagged tea undergoes a crush-tea-curl process, and matcha will be stone milled. The history and diversity of tea artisans over the years have allowed for an explosion of aromatic expression from a single plant that was unheard of as recently as the 1600’s. Tea processing innovation continues to build on itself and reflect the needs and tastes of producers and drinkers as time goes on.
Barry Donnelly, Mad Monk Tea
Founded in San Diego, each tea purchased supports organic and regenerative farmers around the globe.