Tea is harvested – or plucked – several times in a season depending on the country and weather conditions.  As soon as the newly picked leaves reach the factory, processing begins.          

The processing varies for the different types of teas:

Black tea goes through the whole process from withering, rolling, roll breaking, fermentation to drying.

Green tea is not given the withering treatment.  Immediately after it is plucked it is placed into a large "steamer" and heated  to over 160° F.  This softens the leaves for rolling and keeps the juices from oxidizing.  The leaves are then rolled and dried again and again until crisp. The repeated rolling liberates the juices which will remain inside the leaf giving them their flavor as well as their characteristic twist.    

Oolongs are slightly withered, fermented, fired rolled, briefly fermented again, fired again and finally re-fired before packaging.  Green oolongs have the shortest duration of fermenting while the dark oolongs have the longest and are generally brown in color.

White teas are the least processed tea. They consist of only the top of the tea bush, the tea bud, and are picked before they open.  They wither a short time and are then dried.

Below are explanations of some of the terms used above.

WITHERING - The leaves are thinly spread to wither either naturally (where the climate is suitable) or by means of heated air forced over the withering racks.   Withering racks are either stretched cloth or wire mesh.  This usually takes 18-20 hours.  The object is to evaporate much of the teal eaf's water content (approx 35%) so that the leaf becomes soft and pliable.  If the leaves are brittle, they will break apart like an old dry leaf in the fall during the next stage. 

ROLLING - From the withering racks the soft, green leaf passes to the rolling machinery where it is twisted and rolled to break-up the leaf cells and liberate the juice, which gives tea its flavor.  The first important chemical change starts here when the juices, which remain in the leaf, are exposed to the air and development of the essential oil begins.

The rolling table is a circular table where the tea leaves are poured into an open bottomed round box that rotates under pressure, crushing the tea against the top, sides and surface of the table.  During this 1–3 hour process the leaves receive their characteristic twist.  A well twisted leaf will affect the rate of brew for a balanced cup. A broad open black leaf will result in a pungent and less flavorful brew. 

In the third step, ROLL-BREAKING, the tea from the roller emerges as twisted lumps, which are broken up by vibrating coarse mesh sieves or roll breakers.  The fine leaf, which falls through, is taken to the fermenting rooms, while the coarse leaf is returned for further rolling.

OXIDATION OR FERMENTATION - The oxidation that started in the rollers is completed in the Fermenting Room.  Here the tea leaves are spread on cement or tiled floors (sometimes on glass or cement tables) in a cool, damp atmosphere.  The leaves undergo a further chemical change through the absorption of oxygen, and turn a bright copper color - like a new penny.  During this process the oxidation is largely responsible for the flavor, strength, body & color of the black tea.    A shorter fermentation will result in a more pungent tea while a longer fermentation will result in a more flavorful liquor with a deeper color.

The fifth step is the DRYING OR FIRING - The purpose of this is to arrest further oxidation, and to dry the leaf evenly and thoroughly without scorching it.  The automatic tea drier consists of a large iron box inside which the leaves, spread on trays, travel slowly from top to bottom with a continuous blast of hot dry air forced into the box.  Careful regulation of the temperature and of the speed at which the trays move is the main factor in successful firing.

Firing destroys the bacteria & enzymes that are present in the fermentation process.

If a tea is fired too quickly the outer layer is hardened but the center is moist. The tea will lose its quality and may become moldy.   If the temperature is too high the tea will be flat, if the temperature is too low the tea will have a stewed taste to it.

About the Tea Taster

Simpson & Vail are purveyors of fine tea with an on-line store and a retail store.  At Simpson & Vail you will find a wide selection of Teas, Coffees, teaware, and food related items.  If you are in the area of Brookfield, Connecticut stop by and visit them.  Each Saturday from 10 am - 4 pm they offer samplings of 4 teas.  Whether on-line or in-person, Simpson & Vail is a great place to explore new teas or to simply indulge in your long time favorites.