This guidance outlines the standardized process for preparing black tea samples for sensory evaluation. Following these steps ensures consistency and reliability during quality assessment.
1. Raw Material Requirements
- Harvesting Time: Use spring or summer tea shoots.
- Leaf Standards: Pick one bud with two leaves, leaving the fish leaf behind.
- Control Sample: Use other black tea cultivars, such as Yinghong No. 1, Yunkang No. 10, or Qianmei 419, as controls for comparison.
2. Processing Techniques
2.1 Withering
- Leaf Spread: Evenly spread fresh leaves on withering mats or bamboo trays at a density of approximately 0.5 kg/m².
- Conditions:
- Temperature: Maintain room temperature at 20°C–25°C.
- Humidity: Maintain relative humidity at ~70%.
- Process:
- Turn the leaves 2–3 times to ensure even withering and proper airflow.
- Duration: Wither for 6–12 hours.
- During the rainy season:
- Spread leaves thinly.
- Use forced-air withering and install exhaust fans.
- Extend the withering time appropriately.
- Withering Completion:
- Leaves change from bright green to dark green.
- Surface gloss fades.
- Leaves feel soft, and stems bend without breaking.
- Leaf moisture content reduces to approximately 65%.
2.2 Rolling and Cutting
- Step 1: Lightly roll the withered leaves into strips.
- Step 2: Use a small rotorvane machine or a crusher to further roll and cut the leaves.
- Post-Processing: Sift the rolled and cut leaves to prepare them for fermentation.
2.3 Fermentation
- Conditions:
- Temperature: Maintain room temperature at 22°C–28°C.
- Humidity: Keep relative humidity above 90%. Spray clean water on the floor or cover tea leaves with a moist cloth if humidity is low.
- Duration: Ferment for 30–60 minutes.
- Completion Indicators:
- Green grassy smell disappears.
- Floral and fruity aroma develops.
- Leaves turn orange-yellow or start showing red hues.
2.4 Primary Drying
- Equipment: Use a small drying machine.
- Temperature: Set to 100°C–110°C.
- Duration: Dry until the moisture content is 15–20%.
- Post-Drying: Remove tea and cool it to room temperature, allowing moisture to even out before final drying.
2.5 Final Drying
- Temperature: Set to 80°C–90°C.
- Drying Endpoint: Tea moisture content reduces to 5–6%.
2.6 Cooling and Packaging
- Cool the tea to room temperature before packaging.
- Store the packaged tea in specialized equipment designed for preservation.