A new concept.
Bedi & Bedi, Bangalore (B & B), set about this task in 1991 and made some startling findings. The first experiments were carried out with ultrasound which achieved 98% rupture. This line of experimentation was given up because air is not a conducive medium for the conveyance of ultrasound. Experiments were conducted by submerging withered leaf in water. This was not a practical option and was abandoned.
The next line of approach was to freeze withered leaf at temperatures substantially below the freezing point. Thawed shoots recorded cell rupture exceeding 95%. The percentage difference of cell rupture in leaf and stem was insignificant. Having achieved 95% cell rupture in the shoot (in its whole form), only a sizing operation was required.
B & B trials involved conveying withered leaf through a freezing chamber to freeze the shoots. Freezing time will vary according to the refrigeration equipment installed. This can be from two to six hours. The shorter the period, the higher the capital and operational cost. Withered leaf comes out in the form of frozen whole shoots. These are thawed and surface moisture is removed in perforated high-speed spinners. These shoots, with 95% cell rupture, are fed into a sizing machine. Various types of sizing machines are available to size the leaf according to the setting. The sizing process is 80% efficient. If you wish to make 80% Brokens, Fannings, or Pekoe Dust, the setting will do it. In other words, you can dictate grade percentages without worrying about liquors.
The benefits of this system are as follows:
* allows exploitation of 95% of leaf liquor potential.
* the heating of leaf in CTC cutting process or LTP is eliminated.
* after freezing, there is no latent heat in the leaf.
* sizing machines have a clean cut action, so there is no hammering or crushing/squeezing of leaf.
* due to even particle size, fermentation and drying are even, sorting is virtually eliminated, and grades are totally even in density.
* lack of handling in the sorting room preserves liquor characteristics.
If cigarette tobacco can be sized in the way that it is, shoots can also be converted to a grade of your choice.
Producers will miss the fiber and the tea waste! Precision sizing machines do not pulverize and skin the stem in the way that Rotorvanes, CTCs, and LTPs do.
A Few Likely Posers
What is the tea like? It gives substantially higher cuppage per kg. How can it be different? 95% of the cells have been exploited instead of only 70%. The bio-chemical composition of the leaf has not been altered in any way,
What will the market reaction be? Leaf appearance and make will depend on the type of sizing equipment used. In any case, did CTC look like Orthodox? With the additional cuppage per kg, the buyer/blender should pay a premium for it.
Bedi & Bedi, 18/5 111 Cross Road, Nandi Durga Extn, Jayamahal, Bangalaore - 560 046, India. Tel: (91)(80) 3331388, Fax: (91)(80) 3332764; E-Mail: firstname.lastname@example.org.
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|Title Annotation:||Taking Tea Manufacture into the 21st Century, part 2|
|Publication:||Tea & Coffee Trade Journal|
|Date:||Nov 1, 1998|
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