Extraction process of instant tea

The basic steps in the preparation of instant teas are extraction of tea solids from fermented but unfired tea leaf, black tea, or green tea, followed by concentration of the extract and drying of the concentrate to a powder.

Instant tea processing begins with extraction of the selected tea leaf blend. Generally a fermented black tea type is used – one chosen for reddish color, relative freedom form haze and strong flavor when brewed. The extraction process is one with heated water in a static system consisting of three to five cells.

Modern extraction systems are based ion counter-current flow and either batch or continuous systems may be used.  About ten parts of water are combined with one part of tea leaves by weight in the extractors and extraction is carried out at temperatures between about 60 ° C and 100 °C for 10 minutes.

Concentration of the extract is effected by evaporation of the water under reduced pressure at a moderately elevated temperature and during this process various methods for trapping the escaping volatile compounds have been devised. These trapped volatiles are concentrated and retained for incorporation into the final dried product.

The yield of solids during extraction frequently ranges from 25% to 35%. To maximize aroma preservation a process known as aroma stripping can be instigated between extraction and concentration. The aroma is removed through the medium of a stripping gas and is quickly fed back to existing tea concentrate.
Extraction process of instant tea