Why isn't high-grade matcha astringent?

Why Does High-Quality Matcha Lack Astringency?

Astringency primarily stems from polyphenols (such as catechins) in green tea, which are easily released under high temperatures or oxidation, resulting in a bitter taste. High-quality matcha minimizes astringency through the following methods:

1. Raw Material Selection:

   • Young leaves (e.g., first-flush leaves) are used, which contain lower tannin levels and fewer astringent compounds.
   • Shade-growing: Tea plants are covered for weeks before harvesting to boost chlorophyll and amino acid synthesis (e.g., L-theanine) while suppressing polyphenol production. This enhances umami and counteracts astringency.

2. Processing Techniques:

   • Steaming: Leaves are steamed immediately after picking (not pan-fired), rapidly deactivating enzymes to reduce oxidation and preserve umami components.
   • Fine Grinding: Whole leaves are milled into ultra-fine powder (particle size: 5–10 μm), ensuring even release of amino acids rather than bitter polyphenols.

3. Brewing Method:

   • Brewed with warm water (70–80°C), not boiling water, to avoid extracting astringent compounds.
   • Rapid whisking (e.g., with a chasen) disperses umami evenly, reducing bitterness.

In summary, premium matcha optimizes cultivation, processing, and preparation to maximize umami amino acids while minimizing polyphenol-induced astringency, delivering a smooth flavor profile.