Highly precise tea fermentation process to ensure the quality of Tea

The fermentation step in tea processing, which refers to how much a tea is allowed to undergo enzymatic oxidation before drying, is critical in determining the final tea's quality. Tea can be classified as black, green, white, or oolong based on the degree of fermentation. Among these, the most fermented type of tea is Black tea.

Presently, tea tasters estimate the level of fermentation of tea by monitoring changes in color, smelling the tea, and tasting an infusion of tea. These methods are biased, intrusive, consume a lot of time, and are inaccurate, which compromises the quality of the produced tea.

The research mainly focuses on the best optimum time period for the fermentation process considering the external environments. So far, the withering process has taken precedence over the quality of Tea. Similarly, our automation is working on it.

Here we mainly focused on how the variation of physical parameters (temperature and humidity) will affect the fermentation stage of the tea manufacturing process. The temperature is directly related to the oxidation of polyphenolic compounds in tea.

During the process, catechin compounds react with oxygen during oxidation to produce two compounds, namely theaflavins (TF) and thearubigins (TR). These compounds determine the aroma and taste of the tea. Also, fermentation changes the tea color to coppery brown and causes a fruity smell. Hence, the fermentation process must stop at the optimum point as fermentation beyond the optimum point destroys the quality of the tea.

Facts to know;

  • Fermentation reaction starts as soon as leaf is damaged during rolling and roll breaking
  • The quantity of TF & TR formed during fermentation depends on the Period of fermentation and Temperature
  • The high temperature will lead to the rapid formation of TR resulting in dull-colored liquor
  • TF to TR ratio of 1:10 gives ideal liquor color

It’s almost impossible to take the fermented tea at the right temperature manually. Exactly at 80-83 ⁰F (or 26-28 ⁰C) temperature, it is the best condition for the variety. The below graph shows the time and temperature at which the temperature of the tea starts to rise and falls during the fermentation process.

The system continuously monitors the temperature and gives pinpoint accurate alerts/ local indications through the app to extract the tea on point. It sends real-time SMS alerts and LED indications on shifting the tea leaves from withering and fermentation at the right condition. By following the instructions, the quality of the tea can be improved and the energy cost can also be saved significantly.

It is clear that the process of tea fermentation receives a lot of attention from researchers because of its importance in determining the quality of tea, many of which are a combination of machine learning and imaging techniques. IoT is currently gaining momentum in its use to monitor temperature and humidity during tea processing. However, many of the suggestions are in the form of imitation models and have not been applied to actual tea fermentation sites.

For this research, we used an actual tea fermentation site, and as a result, we were able to resolve all of the concerns and provide the optimal solution with accurate data for ensuring higher quality of tea.