Add the lime pulp (with seeds fully removed) to a large pitcher and gently muddle just enough to release juice and loosen the fibers. This step builds structural acidity that balances the natural sweetness of watermelon. Stop early — aggressive muddling creates bitterness and cloudy texture.

Add the fresh mint leaves to the pitcher and press once or twice only. The goal is aromatic release, not extraction. Mint should remain bright green and intact. Overworking it will introduce grassy bitterness and dull the drink’s clean profile.

Place the cubed watermelon in a blender and process until completely smooth and juicy. Add sugar only if the fruit lacks natural sweetness — start small and adjust gradually. The base should taste refreshing and lightly sweet, never syrupy or heavy.

With the blender running on low speed, add the finely grated lime zest and blend briefly — just a few seconds. This technique distributes citrus oils evenly without shredding the peel or releasing harsh pith bitterness.

Pour the blended watermelon mixture into the pitcher with the lime and mint. Stir gently to integrate. Do not shake or whip air into the drink — agua fresca should remain fluid and clean.

Fill glasses generously with ice, pour over the agua fresca, and garnish with fresh mint leaves. Serve right away while bright, cold, and aromatically fresh.