Why does my tea taste astringent or muddy?
Even with good leaves, my tea sometimes feels harsh and drying in the mouth.
Three usual suspects, in order: (1) water too hot — drop 5–10°C, especially for greens and delicate oolongs; (2) over-steeped — cut 30–60 seconds from your timer; (3) too much leaf for your pot — measure with a scale. Mineral-heavy water amplifies astringency, so try a filter. A small amount of astringency (think dry mouthfeel after black tea) is normal; aggressive grip on the tongue means you've over-extracted tannins.