Combine the calcium chloride with 500 ml (17 fl oz/2 cups) cold water. Set the calcium bath aside.
Combine the remaining ingredients and 200 ml (7 fl oz) water in an upright blender and blend until smooth, then transfer to a bowl. Using a teaspoon, drop the wasabi mixture into the calcium bath, placing in no more than 10 drops at a time. Leave in the bath for approximately 1½ minutes or until a skin forms. Scoop out using a slotted spoon, then rinse in a clean water bath. Scoop out again and drain on paper towel. You will need 30 spheres. Serve immediately.