Reverse Spherification is a great technique to master because some liquids aren’t suitable for direct spherification. Adding sodium alginate to calcium-rich liquids like dairy products, or even calcium rich juices like kale, will result in the alginate linking immediately, forming a thick gel as you stir. And, while alginate can readily dissolve in water or juice, it can’t dissolve in alcohol.
When the alginate can’t be added to your liquid, the process is reversed – a technique called Reverse Spherification. In Reverse Spherification, the calcium is added to your liquid, and the drops of liquid are added to a bath of sodium alginate. This results in a thicker gel wall – which also allows for the egg-yolk sized spheres.
Add 1% Calcium Lactate or Calcium Lactate Gluconate to the flavorful liquid.
Most spring and tap water contains calcium, which will react with sodium alginate. Use only distilled water.
Add 0.5-0.7% by weight of Perfected sodium alginate to the water bath, which is 5-7g per 1000g of water.
Rest for 1 hour until thickened and any bubbles have dissipated.
If the flavorful liquid is too thin then it may need to be thickened. To thicken a flavorful liquid simply blend 0.1% Perfected xanthan gum into the flavorful liquid.
Allow any air bubbles to dissipate before moving on.
Use a teaspoon or tablespoon to place the flavorful liquid into the sodium alginate setting bath.
Allow the raviolis to set in the calcium bath for two minutes. Waiting longer will result in thicker sphere wall, while shorter times result in spheres which may pop too easily.
Using a spherification straining spoon, remove the spheres from the bath and transfer to a water bath to rinse.
Spheres are best served immediately. They can be stored temporarily in the flavorful liquid base. Do not use distilled water as the sphere will absorb some of the flavor of the liquid in which they’re stored. Reverse spheres can be prepped in advance, but should be served within 6 hours.