How Do Tea Garden Climate Conditions Affect Matcha Quality?

The climate conditions of tea gardens are a key factor determining matcha quality, primarily including temperature, sunlight, rainfall, and humidity. These elements directly influence tea growth, chemical composition, and final flavor. Specific impacts are as follows:

1. Temperature Influence

• Optimal Range: The ideal temperature for matcha growth is 15-25°C. Excessively high temperatures (above 30°C) accelerate leaf growth, resulting in thicker leaves and increased fiber, reducing tenderness and umami. Conversely, low temperatures (below 10°C) slow growth and decrease amino acid accumulation (e.g., L-theanine), compromising matcha’s fresh, sweet taste.
• Seasonal Variation: Spring (especially April-May) provides mild, stable temperatures ideal for harvest. During this period, tea leaves accumulate more nutrients, yielding peak quality.

2. Sunlight Influence

• Shading Technique: Matcha requires 20-30 days of shading before harvest, reducing light intensity (typically to 70-90% of full sunlight). This promotes chlorophyll synthesis, deepening leaf color while lowering catechin (bitter compounds) and increasing L-theanine (umami compounds), enhancing matcha’s color and flavor.
• Light Duration: Short-day conditions (e.g., spring) aid amino acid accumulation, whereas intense light heightens bitterness and reduces quality.

3. Rainfall and Humidity Influence

• Rainfall: Moderate rainfall (1,000-1,500mm annually) ensures adequate hydration for growth. Excessive rain causes waterlogged soil, triggering root diseases or diluting flavor compounds. Drought hardens leaves, affecting post-grinding fineness.
• Humidity: High humidity (70-80%) maintains leaf tenderness, but levels above 85% encourage mold growth, contaminating leaves. Low humidity dehydrates leaves, diminishing matcha’s freshness and aroma.

4. Other Climatic Factors

• Fog and Breezes: Foggy environments (e.g., Japan’s Uji region) modulate light and humidity, intensifying umami and aroma.
• Season and Geography: Temperate maritime climates in major matcha regions (e.g., Japan) provide stable temperature, humidity, and shading conditions—foundations for high quality. Climate change (e.g., extreme weather) disrupts growth cycles, causing quality fluctuations.

In summary, ideal conditions (mild temperatures, moderate shading, balanced rainfall) optimize matcha’s color, flavor, and nutrients. Conversely, deviations increase bitterness, dull color, or disease risks. Thus, tea gardens often use artificial shading and irrigation to replicate optimal climates, ensuring consistent quality.