Rotorvane
The Rotorvane is the quieter machine in the story, rarely named on a packet but present behind a great deal of the tea that is. It exists to make the older, batch-based orthodox rolling principle continuous.
What it is
A shaft carrying angled blades, rotating inside a cylindrical housing that narrows towards a partly closed exit, generating pressure that lightly crushes and cuts the withered leaf. It is commonly run in series before either orthodox rollers or a CTC line, rather than replacing either.
Where you meet it
Inside the factory rather than on the packet. Most drinkers never see the word, even though a Rotorvane pass is common before both orthodox rolling and CTC manufacture.
How to read it
Read the Rotorvane as a pre-treatment stage, not a manufacturing method in its own right. It prepares leaf for whichever of orthodox or CTC processing follows it.
A common mistake
Confusing the Rotorvane with the CTC machine itself. Both crush the leaf, but the Rotorvane is a lighter, continuous pre-treatment often used ahead of a CTC or orthodox line, not the cutting stage that defines CTC.
Sources
- the Rotorvane is a continuous leaf-disruption machine, a central rotor with opposed vanes inside a ribbed outer jacket, developed to make the orthodox rolling principle continuous, and often used as a pre-treatment stage before a CTC line. Willson & Clifford, eds., Tea: Cultivation to Consumption (Chapman & Hall, 1992)