Mix water and sodium alginate until fully dissolved
Let the mixture rest to remove bubbles
Prepare a calcium chloride bath in a separate bowl
Mix juice, sugar, and calcium lactate in another container
Drop the juice mixture into the calcium bath using a dropper or spoon
Let the droplets sit briefly until a gel membrane forms
Stir gently to keep the spheres from sticking together
Remove the boba with a slotted spoon
Rinse the boba in clean water
Store the popping boba in flavored syrup or juice in the refrigerator