How tea bag is made
The leaves floated into his boiling water and, lo, tea was created. Traditional withering practices call
for manually spreading the leaves in thin layers and exposing them to the open air for 18-20 hours.
Modern factory methods place the leaves in troughs, perforated drums, or tunnels and expose them to
mechanical blasts of hot air. This process oxidizes the polyphenols, or tannins, the primary active
ingredient, and turns the tea leaves a coppery color.
Tea bags are composed of two main ingredients, processed tea leaves and filter-paper.
The top tea leaves and leaf buds are hand-picked from the plant. The leaves are then subjected
to several processes including withering, rolling, drying, cutting, and blending. The intensity
and duration of each process differs according to the type of tea. The filter paper is made
primarily of abaca.
The Manufacturing Process: Crushing:
The leaves are crushed either by hand or on rotating tables called rolling machines. Either method twists
the leaves so that they are eventually coated with their own juices and torn into smaller pieces. Some
companies employ high-tech machinery similar to tobacco-cutting machines to crush and tear the tea leaves.
Black tea leaves are mechanically dried using a high-temperature method to seal in juices and flavor.
This process turns the leaves to their characteristic black color.
Oolong tea leaves are rolled, dried, and rolled again. The drying time is shorter than that for black tea,
therefore the fermentation is less natural and half or less of the polyphenols are oxidized. Green tea leaves
are steamed within 24 hours of harvesting, using either moist or dry heat in perforated drums or hot iron pans.
This process destroys enzymes and prevents fermentation and the oxidation of polyphenols. Herb tea is simply bundled
together and hung upside down to air dry.
After the leaves are dried, they are brought to a mill room, where they are cut with a rotating blade
into varying degrees of fineness, depending on the type of tea. The cut leaves are further refined by
sifting them through mechanical sieves with meshes of varying grades. The tea used in tea bags are
typically broken-grade or smallsized teas because they require a shorter brewing time.
The leaves are blended according to company recipes to achieve a uniform taste and texture. Most teas
are a blend of between 20-40 types of tea leaves. The blending process may also include the addition
of natural flavorings such as cinnamon, orange peel, nutmeg, cloves, chocolate, licorice root, peppermint,
ginger, crushed hibiscus flowers, fennel seeds, and chicory root.
The processed and blended tea leaves are stored in hoppers that hold up to 800 pounds (363 kg) of tea.
Flow tubes connect each hopper to a doser wheel. The doser wheel resembles a Ferris wheel with small
chambers in the place of seats. Air pushes the leaves through the flow tube and into the wheel which
separates the tea into the chambers in pre-measured amounts, usually two grams.
Tea bag assembly:
Two large rolls of filter paper are fed over the top and underneath the doser wheel. As each chamber
arrives at the bottom of the doser wheel, it releases the tea onto the bottom paper layer of paper
as it moves along a conveyer belt. The top layer of paper is lowered onto the lower layer so that
each measure of tea is sandwiched between the two layers.
A conveyer belt moves the three components to a heat-sealing drum fitted with an indentation pattern.
The drum quickly seals the paper along the indentation lines. The timing of this process is closely
monitored because too much heat would adversely affect the tea.
The sealed paper continues along a conveyer belt until it reaches a perforation blade that is calibrated
to cut the paper into precise squares. After a string and tag are stapled to the bag, they are dropped
into pre-printed boxes.
Tea tasting is an art. Cups of brewed tea are lined up along with bowls of the tea leaves from the
same batch. Tasters slurp the tea to the back of their throats, atomizing the tea so that they
can taste it and smell it at the same time. The tasters also examine the unbrewed tea leaves to check
for cleanliness, purity, and freshness.
Each tea is blended to achieve a particular taste and appearance, therefore company recipes are strictly
followed for consistency. Consistency is also maintained through computerized control systems that regulate
the speed of the manufacturing machinery and heating processes. The systems alert, plant workers to
breakdowns and jams.
Wishing you all the best,