Remove stems and slice strawberries. Bring a pot of water to a boil.
Place the strawberries, lemon juice, and sugar in a metal or glass bowl. Place the bowl on top of the open pot (this is called a bain-marie or double boiler). Reduce water to a simmer.
Cover bowl and cook for 20-25 minutes, stirring regularly.
Reserve 200g (¾ cup + 2 tbsp) of liquid for the sphere liquid. Save the strawberry pulp for other uses, such as waffles or a dessert.
Mix together strawberry juice, distilled water, and sodium citrate.
Pour the strawberry juice mixture into a blender and while blending on low speed, slowly sprinkle the Perfected sodium alginate into the liquid. Continue blending for two to three minutes.
Pour the mixture into a covered container and let it sit while the perfected sodium alginate hydrates. Allow the mixture to settle until all the air bubbles have been released. The hydrating and air bubble release process could take 1-2 hours, so be sure to not rush this process.
Mix the water with the calcium chloride until it dissolves completely.
Using a perfect caviar maker or a rapid caviar maker, let the strawberry liquid fall into the calcium bath drop by drop.
If you are using the rapid caviar maker be sure to not overfill the pipettes. Over filling the pipettes will make the cleaning process very difficult.
If you are using the spherificator, fill the reservoir at the top with your flavorful liquid. Create a rapid vortex with your calcium bath as the spherificator drops come out quickly. Press the button on the spherificator to dispense, and move your spherificator in the opposite direction of the vortex to avoid the spheres from sticking together.
Using a spherification spoon, stir gently for 30-45 seconds. Stir the bath without touching the spheres.
Transfer spheres to the rinsing bath, and stir gently again. This removes the bitter flavor of the calcium bath.
Remove spheres from the rinsing bath with a spherification spoon and blot dry on paper towels before serving.
These spheres are best served immediately. You may store them in any remaining strawberry juice that does not contain sodium alginate. If you place the spheres in the sodium alginate strawberry liquid it will gel the liquid. However, the skin on the spheres will continue to harden until the spheres are solid.