The Art and Science of Tea Picking and Processing at Zealong Tea Estate

January 19, 2017

new zealand pure tea2Three times a year, for 20 days at a time, Zealong is harvesting its most tender leaves and processing them in their state-of-the art factory.

The overall quality of tea is determined by the quality of tea bushes, the plucked tea leaves and the process in which the leaves undergo to make the final product. For each harvest, world-expert tea masters fly to Zealong Tea Estate to work with the already highly trained and experienced pickers and tea masters at Zealong in order to ensure there are no compromises at any step of the way. It’s a labor-intensive 24 to 36 hour process but anyone who has drunk Zealong tea, knows the end result is worth all the effort.

quality Zealong tea organically grown and hand pickedZealong tea is organically grown in the Waikato, New Zealand where tea bushes (camellia senensis) thrive. The tea plant absorbs its surroundings, so the Waikato’s pristine air, soil and water are essential ingredients to the purity of Zealong tea. 100% of the tea leaves are sourced from the 2.5 acre estate ensuring that the leaves are free of chemical sprays and of the highest quality.


It has become increasingly common with the rise of technology, tea plantation scale and increasing labor costs for mechanical harvesters to be used in commercial tea operations. In mechanical harvesting a big machine is driven over the top of the tea bushes, clippers on the front and a vacuum in the rear sucking up the mechanically-cut leaves. It’s a fast and efficient way of picking, however in this manner there will be more broken leaves and partial flushes reducing the quality of the tea. To produce high quality tea, such as that produced at Zealong Tea Estate, the top leaves and flushes are picked by hand.


The Top 3 Leaves at Zealong quality New Zealand tea3 The tea masters oversee the careful selection of when and which leaves to pick in the fields. The leaves are not picked until the bud at the top of the bushes have grown to half the size of a full grown leaf. The pickers pluck just the the top three, most tender and most flavorful leaves.

The 2.5 acre estate in the Waikato’s unspoilt environment can product as much as 100 tonnes of tender leaves which are then processed in the state of the art tea factory.

Before learning about tea processing, I erroneously assumed that different teas were derived from different tea leaves. In fact, green, oolong and black teas all start out the same way – picked from the camellia sinensis bush. It is the subtle changes to the tea processing which creates the different appearance, aroma and taste of the different tea types.

Withering (or wilting)

tea leaf withering tea process Zealong tea in the USA2Withering is the process by which the leaves lose 25% - 50% of their moisture. Natural proteins in the leaves break down, caffeine levels rise and the aroma and taste develops. Leaves for green tea go through a short withering period whilst leaves for oolong and black tea are withered for longer. In many commercial operations the withering happens outside where leaves are laid out on tarps near roads and paddocks, exposed to animals and the elements. At Zealong, the process is highly controlled by monitoring and adjusting the humidity, temperature, air-flow and density inside the on-site Zealong tea house. The process involves stirring to distribute moisture evenly. The tea master determines the withering complete by using science (such as the weight of the leaves) and their art comes in by using their sense of smell and touch. 


Tossing is a continuation of the withering process and the initiation of the oxidation process. The process of oxidation includes initiation, oxidation and fixing (or stopping) the process at the desired stage. Oxidation initiation in many mass produced commercial tea operations is often achieved through macerating the leaves, quite often using a CTC (cut tear curl) machine to quickly expose lots of the inside of the leaf to oxygen and thereby starting the oxidation process. Zealong use a much gentler and slower way of initiating oxidation called tossing. This is where oxidation is initiated through gentle tumbling of the leaves.


zealong organic tea flavors USA3Oxidation is the process of browning the leaves. Depending on the type of tea being produced, the tea maker may prevent oxidation altogether (such as when making green tea) or fully oxidize the leaves (such as black tea) or somewhere in between (when making oolongs). There are a number of chemical reactions that occur in this process such as the chlorophyll in the leaf breaks down and the tannins are released, and these changes create the flavor, color, aroma and strength of the tea.

Heat, humidity, air flow, light and processing time need to be controlled in the oxidation process. At Zealong, in their specialized tea house, the tea masters have full climatic control in their oxidation rooms ensuring this process is perfected. This is not ‘one process’ as such but monitoring and adjustments are made until the tea leaf has reached its desired level of oxidation.

De-enzyming (or fixing or ‘killing the green’)

Tea Processing Chart The Kiwi Importer Zealong Organic Oolong TeaDe-enzyming is the process of killing the enzymes in the leaves and thereby stopping the oxidization process. For green tea this happens early in the process to prevent the leaves from oxidizing at all and this is what gives green tea its high catechin levels. It’s important to time this process just right for the oolong teas (and oolong variations occur with different timing) but is unnecessary for black tea which is fully oxidized.

De-enzyming requires heating the leaves to around 150 F depending on the size and thickness of the leaves and can be achieved through steaming, baking or roasting which also account for tea variations. Extreme control of the fixing process is required for quality tea.  It’s a relatively short part of the process but failing to de-enzyme properly and the tea will continue to oxidize, or fixing for too long will result in too much loss of moisture.

Rolling and Shaping

zealong factory tea rolling tea processes organic tea quality teaPressure is used to roll the leaves into the desired shape. Long and curly, semi-rounded or tightly-rounded. This process is not just about the leaf shape, when rolling the leaves secrete juices altering the flavor and liquor color. The rolling and drying process isn’t just a linear set of actions but several repetitions of rolling and heating, rolling and heating.


Drying is the final step in the process and is done to further develop the flavor, color, aroma, and make the tea shelf stable. There are two parts to this process, a short, high heat process followed by a longer, lower heating time. Again, a huge amount of control and care of the temperature, air flow over tea and speed of drying is critical in this step. Drying too slow and the leaves will be stewed, but over cooking the leaves is just as detrimental to the finished product. 

Cooling, grading and packaging

zealong tea in the USA organic loose leaf teaZealong tea is careful graded and packaged before it is sent to the finest tea houses around the world. When all the possible variations are considered through these complex processes its not a wonder that there are seemingly infinite variations in tea types - and that there is so much variation between the quality of different tea brands. Tea processing is truly part art and part science.

Zealong tea is available in the USA from The Kiwi Importer. It is available in loose leaf: green, pure oolong, aromatic oolong, dark oolong and black as well as in biodegradable, non-bleached, non-glued, natural-fiber pyramid bags: green, oolong and black.

#New Zealand #sustainably sourced #eco-friendly #oolong tea #green tea #black tea #organic tea #how to process tea


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