When sourcing Wolfberry tea, the primary quality indicators are size, color, and moisture content. Look for berries categorized by grain count per 50g (e.g., 280, 370, or 580 grains); larger berries generally command higher prices. The color should be a natural dark red or purple-red, not artificially bright, which may indicate sulfur fumigation. The moisture content should be below 13% to prevent mold while maintaining a chewy texture. Additionally, ensure the polysaccharide content, the active health component, meets the standard of at least 4.5%.