Weak froth in ceremonial matcha usually comes down to water temperature (too hot kills the foam), whisking technique (using a W-shape motion, not circles), or stale matcha. Before you spend on a new chasen or premium powder, try cooling your water to 160–170°F, sifting your matcha, and whisking briskly in a zigzag pattern for 30–45 seconds. These fixes cost nothing and often solve the problem.