Serious Eats: Recipes
Sweet Coconut Soup with Fruit Pearls
Spherification is the process of immersing sodium alginate-enriched liquids in a calcium chloride water bath. The reaction between these two powders produces an instant gel on the surface of water droplets while the interiors remain liquid. With a little practice, you can create pearls of liquid that burst like caviar in the mouth.
Sweet dessert soups are common in East and South East Asia. I'm partial to those made with coconut milk, which make a silky base for inclusions of fruit, red bean, tapioca pearls, and jellies. Spherified fruit juices combine the best of these add-ins: intense fruit flavor with a dynamic, juicy texture. I used guava juice, but use whatever flavors (perhaps in combination) you like. You can even dilute flavored syrups (like ginger or cinnamon) in water for your fruit juice. Just stay away from acidic ones like lime juice, which in my experience do not set as well.
You'll have to experiment with soaking times for the spheres in the calcium chloride bath. Start checking on them after one minute; they will harden the longer they spend in the bath. Skins will also thicken over time, so make spheres close to service time.