SOSA Sodium Alginate – Molecular Gelling Agent

Sodium Alginate is a natural hydrocolloid derived from various types of brown algae, including Fucus, Laminaria, and Macrocystis. It is best known for its ability to form gels in the presence of calcium, making it a key ingredient for spherification techniques in modern gastronomy.

This gelling action allows chefs to encapsulate liquids in delicate, thermo-reversible membranes, creating visually striking “caviar” pearls, spheres, and other textures that deliver an intense burst of flavour in the mouth. Its versatility has made it a staple in both avant-garde pastry and savoury cuisine.

Functional Properties

• Gels in contact with calcium (direct or reverse spherification)

• Thermo-reversible when heated

• Acts as a thickener in the absence of calcium

• Cold or hot soluble (with better results when hydrated cold)

How to Use

• Direct Spherification: Add alginate to the base liquid and blend vigorously. Rest to remove air bubbles.

• Reverse Spherification: Dissolve alginate in mineral water for the external bath; the base liquid should contain calcium or calcium gluconolactate.

• Add sugar to aid incorporation. Use a hand blender to avoid clumping.

Recommended Dosage

• 5 g per kg of preparation (for both spherification and thickening purposes)

Applications

• Molecular “caviar,” pearls, spheres

• Vegan ravioli or encapsulated sauces

• Fruit juices, purées, and dairy foams (reverse spherification)

Observations

• Requires pH ≥ 4 and water content ≥ 80% for effective gelling

• Avoid fatty or alcoholic mediums, which interfere with hydration

• Use mineral water for reverse spherification

• Does not gel without calcium—will only thicken

Suitability

• Suitable for vegetarians and vegans

• Gluten-free and allergen-free

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DIRECT SPHERIFICATION:

To make direct spherification, basically three baths are used:

1. In the first we will put the product that we want to spherify together with Alginate. We will apply turmix, leaving it at rest until the total loss of air. The acidity level of the product must be taken into account: if it has a pH of less than 4 in this same bath, we will add sodium citrate (pH Kit) in the right amount. If we exceed it, we will give the product a bad taste.
2. In the second bathroom with Chloride. They will put 5 to 8 g per liter, depending on the size of the sphere. The Alginate reaction occurs when it comes into contact with the Chloride bath, forming a layer that will gel inwards. The more time elapses in the bath, the more gelled it will be, until it is completely gelled.
3. In the third and last bath we will put water, which will be used to clean the spheres, basically to remove the bad taste produced by calcium chloride.

REVERSE SPHERIFICATION:

Those liquids, which by their very nature contain calcium, such as dairy products, must be spherified in reverse, that is, inverting the first two baths. The same will happen with products to which Gluconolactate is added. We also work with three baths:

1. In the first we will put the product with its own calcium or with Gluconolactate. If the product does not have the appropriate density, we will add 6 g of Gelespessa (2 g Xanthan) per kilo, in order to obtain enough weight so that the sphere we form can be submerged in the second bath.
2. In the second bath we will put a liter of mineral water (without calcium) with 5 g of Alginate.
3. In the third and last bath we will put plain water to clean the spheres. Thanks to the inversion of baths, a sphere is obtained that always remains liquid on the inside, since the layer that forms gels on the outside.

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