|CTC Teas-From Field to Cup
How They Are Made
|There are basically two manufacturing methods for black tea, CTC or cut-tear-
curl, and traditional orthodox leaf manufacture. Most likely you have been
drinking CTC teas for years without even knowing it, as they are primarily used
to fill tea bags.
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|With the next method, continuous oxidation machines, the chutney is fed into the automatic dryer and carried on a
conveyor belt where it passes beneath ultraviolet lamps, which activate the polyphenol oxidase and stimulates
oxidation. The ultraviolet light also kills bacteria and microbial contaminants. This method is used in areas with high
humidity and for fast, high volume production of average grade CTC tea leaf.
The most efficient firing method, though, is with the Fluid Bed Dryer, which blows the tea
particles on a stream of hot air (240-250F), reducing the moisture content to just 2-3%. This
method ensures that all the pieces of leaf, no matter the size, are evenly dried.
After finishing the oxidation stage the leaf is cooled, sorted one last time, graded, and then
packaged for storage or sale.
Now that you know the steps involved in making the black tea in your favorite bagged tea
brand, it helps you to appreciate even more the handy, tasty little tea bag you slip into your
mug, when sitting down for a quick cup of tea. Enjoy.
The CTC processing method be-
gan in the 1950's because of the in-
creasing popularity of tea bags. Designed to produce
a less bulky tea that would brew more quickly and
with an even, robust flavor, CTC teas are directly
opposite of traditional orthodox teas, that concen-
trate on drawing out unique flavor and style from
CTC teas are less cost-
ly to produce, yet
many of the growers
producing them are
actually losing money.
That's because 95% of
tea produced today is CTC and there is a glut of
tea in the market, driving down prices for everyone.
| The prices have fallen so low, in fact, that many producers can
no longer afford to stay in business any longer and are either
closing or switching over to orthodox tea manufacture. This is a
smart move as today's tea drinkers are becoming more knowl-
edgeable and savvy about tea, driving the demand for more
specialty orthodox teas.
The production method for CTC black tea differs somewhat from
traditional orthodox black tea manufacture. After withering, the
fresh leaf needs to be chopped into smaller pieces.
The blades used to chop the tea are ex-
tremely sharp and fast moving so it's im-
portant that any extraneous materials,
such as sticks or small rocks be removed
before the leaf goes into the machine.
This initial step is called pre-conditioning
and is a combination of sifting and shred-
ding. A machine called a green leaf sifter
with a perforated, vibrating tray, feeds a
continuous flow of withered leaf through
while separating out any sticks, stones,
The sifted leaf then goes into the green
leaf shredder, a cylinder to which very
sharp, light, and well balanced knives
are attached. Rotating at 2,500 rpm's the knives shred the leaf as it goes through.
To ensure uniform particle size the cylinder decreases in diamet-
er along the length of the shaft so all pieces are the same size
when they emerge. This step completes the preconditioning.
Next comes a series of two rotorvanes for final conditioning.
The rotorvane was developed in 1957 by Ian McTear of the
Experimental Tea Research Station at Tocklain in Assam, India.
The rotorvane is basically a combination tumbler-barrel-drum ranging in diameter from 8 to 18
inches. A central shaft acts as an auger pulling the leaf through
as it crushes, tears, and mixes the leaf. This process generates
heat that continues the enzyme activity inside the leaf, spreading
the juices to the surface, which begins the oxidation process.
For final conditioning the leaf is passed through the first rotorvane
with an open end and only 8 inch diameter, crushing and compact-
ing the leaf. The diameter of the second rotorvane drum is 15
inches with a sieve plate or screen on the end, further squeezing and mincing the leaf into what
is called chutney.
With final conditioning finished, the CTC leaf is on to rolling, where the chutney will be passed
through a series of four to five CTC rollers. The mechanical rolling machine was invented by a
man named A. Holle, and was first introduced, again in Assam, India, in 1872, at Jorhat. Today,
the mechanical rolling machines are still in use worldwide.
The rolling machine used for CTC production has two identical
stainless steel rollers with sharp cutting teeth mounted parallel
to one another and attached horizontally. The rollers rotate at
different speeds, one fast, one slow, and in opposite directions
from one another.
The chutney is fed from the rear, drawn between the rollers and
chopped and cut into uniformly sized particles. Because the particles are so small there is no
clumping, so the step of roll-breaking, needed for orthodox teas, isn't needed for CTC.
Depending on the climate and location it is at this stage where the tea is
spread out in thin layers in cool, humid air and left to oxidize for 20 to 30
minutes or more. It's at this point that the tea begins to develop the
recognizable aroma and flavor of black tea, darkening in color and devel-
oping the tea chemicals, theaflavins and thearubigins.
The next step is to stop oxidation of the leaf with firing. There are sev-
eral different methods used for firing CTC teas. The first method, drum
oxidation is commonly used in southern India. The chutney is placed in-
side the drum (think clothes dryer) for 60 to 90 minutes. The continuous
revolving motion of the drum guarantees that every bit of the internal
juices are evenly spread over every bit of leaf. Drum oxidation also increases leaf density and
creates a darker leaf, and even granulation of the pieces.