Not every clump is fixable. If your matcha has a dull color, off smell, or tastes bitter and flat, it's likely lost its freshness. Clumps that don't break after sifting and whisking might indicate moisture damage that's already affected the quality.

Check: Look for a vibrant green color and a sweet, grassy aroma. If it's yellow-brown or smells musty, it's time to replace.