An extract of seaweed most commonly used in conjunction with calcium to make coloured and flavourful translucent spheres from just about any liquid.
Sodium Alginate is a gelling agent that dilutes when cold with strong agitation. It can be used to create soft or firm gels, ambient, heat-resistant gels
Sodium alginate can also be used to produce foams and as a thickener.
Applications: Heat stable strong gels. Dessert gels. Structured Foods.
Rate of hydration: Moderate
Comments: Alginates react with calcium to form gels and is therefore used in spherification and reverse spherification.
Gel Strength: Strong gels only in the presence of calcium.
Ph Solubility: 4.5 - 8
Doseage Rates: 0.5% - 1.5%
Making coloured and flavourful translucent caviar-sized pearls from just about any liquid is possible by following a very simple process.
The ingredients used to make the spheres are as follows:
Add Sodium Alginate to the base liquid you want to gel (0.5% by weight) and using a syringe, drip into a calcium chloride bath (0.5% calcium chloride to water). Rinse in a separate water bath and serve immediately.
Reverse spherification follows the opposite process to spherification and allows you to make larger colourful and flavoured spheres from just about any liquid.
The ingredients used to make the larger spheres are as follows:
The liquid-center itself doesn't contain anything that will gel, so the sphere can never become entirely solid. Thus, spheres prepared this way can be kept indefinitely.
Begin with a base liquid.
Performance Colours will add dramatic impact.
NB pH of the liquid should not be below 3.6 and should not contain large amounts of free calcium - a low pH will prevent the alginate from gelling, and too much calcium can cause the alginate to gel before the spheres have a chance to form.
Add Sodium Alginate to the base liquid
Add 1% of the liquid's weight. Blend the alginate with sugar or maltodextrin to disperse the particles, these will prevent the alginate clumping when it is added to the liquid
Whisk in very gradually with a gentle whisking motion .
Leave the liquid to hydrate and stand until clear and free of air bubbles.
Create a Calcium Bath
Add 1% calcium chloride relative to the weight of the water.
Using a syringe, add the flavoured and coloured liquid to the setting bath drop by drop.
Use a Lotus Spoon (or slotted spoon) to stir the setting bath.
Thirty seconds is enough time for a durable membrane to form. Stirring for less time forms a more delicate skin.
Strain the spheres into a separate bowl and rinse
Reverse Spherification follows the opposite process to spherification and allows you to make larger colourful and flavoured spheres from just about any liquid. Add 3% Calcium Lactate to the base liquid by weight. Use a Sodium Alginate bath of 1% relative to the weight of water.
Hints & Tips
Add Sugar or Maltodextrin to disperse the particles, these will prevent the alginate clumping when it is added to the liquid.
Getting the size and shape you want:
As the spheres sink through the setting bath, they form a sturdy skin. The bath should be deep enough to allow the spheres to sink for a second or so before they hit the bottom; working in a shallow bath will cause the spheres to flatten when they strike the bottom too soon.
The roundness of the spheres is affected by two things: the distance the drops fall to the surface of the setting bath, and the viscosity of the base liquid.
Experiment to find the ideal height from which to let the drops fall. A disc shape means you were too high, and the impact flattened the drop. An elongated shape means you were too low, and the drop did not have enough time to snap into a sphere.
Spheres not forming?
Keep in mind that every sphere you prepare removes a small amount of calcium from the setting bath. Eventually, the bath may be depleted of the calcium ions needed to trigger gelling.
If the base liquid already contains calcium, it may start to gel when the Sodium Alginate is added. To avoid this, add Buffer Salt (in liquids with a pH above 4.5 or Sodium Hexametaphosphate for more acidic liquids). Buffer Salt (Sodium Citrate) and Hexametaphosphate (Hex) are ‘sequestrants’ - compounds that mop up excess calcium ions by binding them so that they cannot interact with other molecules.
Rinse caviar pearls thoroughly to avoid after-taste.
Can they be prepared in advance?
RInsing the spheres will not halt the gelling process. They will gradually continue jelling until they lose their liquid centre, however sodium alginate is a soft setting gelling agent so the pearls will remain soft and jelly like. They can be prepared in advance and stored until needed. Store in same liquid they are made from, minus the alginate. Briefly rinse the spheres in clean water before serving.