Ingredients :

• Watermelon — Get it ripe—to know if it is, tap it with your palm. A deep, hollow sound like a drum is a good sign. A dull, muffled sound means leave it on the shelf. No need for the seedless variety; the seeds pass through the blender without any trouble.
• Tomato — A truly ripe tomato, not a supermarket one picked green. Beefsteak, Roma, or even a slightly bruised garden tomato—the shape doesn’t matter, what counts is that it’s red to the core and soft to the touch. A firm tomato will give a flat taste.
• Chia seeds — Optional, but they do something interesting: they swell in a few minutes in the juice and give it a slightly thickened texture, almost like a healthy 8-euro juice bar drink. You can find them cheaply in the organic aisle of most supermarkets.
• Lemon — A standard yellow lemon works just fine. A lime brings a more exotic note that works well with watermelon. In any case, squeeze it at the last moment—acidity changes the color of the juice if you prepare it too far in advance.