Technical difficulties in the cultivation and processing of matcha tea

1、 The ‘double-edged sword’ effect of shaded cultivation

Shading is the soul of matcha, but it is also the most problematic aspect of cultivation.

• The contradiction between precise control of light and temperature and humidity: Although shading can significantly increase chlorophyll and amino acids (bringing a refreshing taste), long-term weak light environments can hinder photosynthesis, leading to a decrease in the disease and pest resistance of tea trees, and even affecting the yield of the following year. At the same time, after building a shading shed, the humidity inside the tea garden increases and the light weakens, which can easily induce diseases such as tea cake disease and white star disease, as well as the growth of malignant weeds such as ferns.
• Strict requirements for technical details: The timing o shading (when one bud and two leaves are first developed), duration (strictly controlled within 20-25 days, short for insufficient freshness, long for reduced yield), shading rate (usually 75% -95%), and greenhouse temperature (ventilation is required immediately if it exceeds 30 ℃) must be accurately controlled. Any error in any link will directly affect the quality of matcha.

2、 Green prevention and control of pests and diseases and soil continuous cropping obstacles

Matcha is a form of “eating tea” (whole tea leaves are ground and consumed), so the requirements for controlling pesticide residues and heavy metals are much stricter than those for regular tea brewing.

• The conflict between high nitrogen fertilization and soil acidification: Matcha tea gardens require about 1.8 times more nitrogen fertilizer than ordinary green tea gardens, but blindly applying large amounts of chemical nitrogen fertilizer can easily lead to soil compaction, severe acidification, and even activation of heavy metals in the soil.
• Difficulty in green prevention and control: Due to the inability to use conventional chemical pesticides, balancing ecological prevention and control with “using grass to control grass and insects to control insects” and ensuring fresh leaf yield in high humidity environments caused by shading is a great technical test. At present, the forefront of the industry is exploring the restoration of the self-healing ability of tea garden ecosystems by screening specific microbial fertilizers (such as Trichoderma spinosum) and immune inducers.

3、 Shortage and lagging breeding of specialized varieties

Not all tea trees are suitable for making matcha.

• Difficulty in variety compatibility: High quality matcha requires specialized varieties with “high chlorophyll, high amino acids, and low tea polyphenols”. At present, most of the raw materials for matcha in China (Guizhou) still come from the improved cultivation of ordinary green tea varieties such as Fuding Dabai, Longjing 43, and Zhongcha 108. Although they have good tenderness, they are not the most ideal matcha genes.
• Long breeding cycle: From excavating endogenous gene resources to directional hybridization combinations, and then to regional trials of new strains (such as constructing a “breeding breeding promotion” system), breeding a truly high-yield and flavorful matcha specific variety requires a long research cycle and huge investment.

4、 Management of processing technology

If the processing chain of fresh leaves grown falls off, their value will plummet instantly.

• Accuracy of withering and baking: Steam withering must be performed within 4 hours after harvesting fresh leaves (steam temperature must be greater than 100 ℃), otherwise the umami ingredients will degrade by 50%. The subsequent four stage baking is the core of reducing bitterness and enhancing freshness, and even small deviations in the temperature curve can change the final flavor.
• The temperature control problem of ultrafine grinding: Matcha requires a grinding fineness of over 800 mesh (particle size ≤ 18 μ m) and no graininess on the tongue tip. But during high-speed grinding, high temperatures are easily generated. If the grinding temperature exceeds 20 ℃, it will cause the matcha powder to oxidize and turn yellow, and the aroma will be completely lost. Therefore, the investment and technical debugging of equipment for low-temperature cold grinding throughout the process are extremely high thresholds.