Iruma matcha powder

Iruma Matcha Characteristics And Growing Conditions

Iruma matcha comes from Iruma City in southwestern Saitama Prefecture, part of the renowned Sayama tea-producing region. This area sits between the Kaji and Sayama Hills, where volcanic ash soil and a mild climate create conditions that shape matcha with distinct flavor characteristics. Iruma holds the highest production volume within Sayama, making it a key player in one of Japan’s three most famous tea regions.

Climate And Soil Conditions

The region’s sandy soil, formed from Kanto loam—a volcanic ash layer—provides excellent drainage that helps tea plants develop glossy, healthy leaves. This soil composition differs from the clay-rich grounds found in southern tea regions. The mild climate between the hills protects plants from extreme temperature swings while maintaining consistent moisture levels. These natural advantages reduce stress on tea plants and contribute to the development of umami compounds in the leaves. The combination of well-drained volcanic soil and moderate temperatures creates an environment where tea plants can focus energy on producing tender shoots rich in amino acids.

Cultivation And Shading Practices

Iruma tea farmers shade their plants for about 30 days before harvest, a practice that sets the region apart from other Sayama producers who often use shorter shading periods. This extended shading reduces sunlight exposure, which triggers plants to increase chlorophyll production and develop higher concentrations of L-theanine. The result is matcha with a brighter green color and more pronounced sweetness. Farmers use reed screens or similar materials to achieve the right balance of shade. Cultivars like Okumidori and Fukumidori are commonly grown here, selected for their ability to produce high-quality matcha under these specific conditions. Many producers now incorporate organic farming methods alongside traditional techniques.

Processing Methods And Flavor Profile

After spring harvest, leaves undergo steaming immediately to prevent oxidation, preserving their vibrant color. What distinguishes Iruma matcha is the Sayama hiire technique—a final drying process that intensifies aroma and brings out natural sweetness. This method applies controlled heat to develop flavor compounds without damaging delicate leaf structures. The resulting matcha displays:

• Rich umami flavor with noticeable depth
• Bright, vivid green color from extended shading
• Sweet, aromatic finish from the Sayama hiire process
• Smooth texture with minimal astringency

Historical Context And Regional Significance

Tea cultivation in Iruma traces back to the Heian period between 794 and 1185, with local legend crediting Kobo Daishi for introducing tea plants to the Kawagoe fields. Production became more structured during the late Edo period as demand grew. Today, Iruma faces challenges common to northern tea regions: limited growing land and higher production costs compared to warmer southern areas. Yet the region maintains its reputation through quality rather than volume. The specific terroir—combining volcanic soil, hill protection, and traditional processing—creates matcha that stands out in Japan’s competitive tea market. This heritage continues to influence how modern producers approach cultivation and processing.