Advanced & modernist · advanced
Spherification
Also: basic spherification, reverse spherification, caviar technique
Forming liquid-filled spheres with a thin gel skin using alginate and calcium.
What it is
Spherification shapes liquids into 'caviar' pearls or larger spheres that burst in the mouth. In basic (direct) spherification, a flavoured liquid containing sodium alginate is dropped into a calcium bath. In reverse spherification, a calcium-rich liquid is dropped into an alginate bath, giving a skin that stops thickening when rinsed.
Why cooks use it: It encapsulates flavour as a liquid with a delicate shell, a signature texture of modernist cooking.
The science
Sodium alginate, a polysaccharide from brown seaweed, gels instantly when it meets calcium ions, which link the alginate chains together. At the surface where the two liquids meet a thin gel skin forms. Highly acidic liquids (below about pH 3.6) stop alginate gelling properly, and liquids already rich in calcium (like dairy) gel prematurely, which is why reverse spherification is used for them.
Acids and bases in cookingMolecular gastronomyFoams and gelsHydrocolloids: thickeners and gelling agents
Step by step
Basic: blend 0.5–1% sodium alginate (5–10 g per litre) into the flavoured liquid with a stick blender; rest it (refrigerated) for a few hours or overnight to remove air bubbles.
Make a calcium bath of 0.5–1% calcium chloride (5–10 g per litre of water); calcium lactate (about 1–2%) tastes less bitter.
Drop the alginate liquid into the bath with a syringe, pipette or spoon from a little height.
Leave pearls 1–2 minutes (larger spheres 2–3 minutes), then lift out with a slotted spoon.
Rinse in clean water to stop the reaction and remove bitterness; serve soon, as basic spheres keep gelling inwards.
Reverse: add about 2% calcium lactate (or use a naturally calcium-rich liquid) to the flavoured liquid and spoon it into a 0.5% alginate bath; rinse and hold in liquid.
Heat and timing
Time: Bath time 1–3 minutes; base must rest to de-aerate (several hours).
How you know it’s right
- Drops hold a round shape in the bath
- A thin, even skin forms
- Spheres burst cleanly when pressed in the mouth
Common mistakes
- Acidic liquid (lemon, passion fruit) without adjusting pH
- Air bubbles so spheres float and deform
- Leaving basic spheres too long so they set solid
- Not rinsing (bitter calcium chloride taste)
Troubleshooting
- Drops form tails or flat discs
- Rest the base longer, drop from closer to the surface, or thicken the base slightly.
- No skin forms
- The liquid is too acidic; raise the pH with a little sodium citrate, or check the bath concentration.
- Spheres turned solid
- Shorten bath time, serve immediately, or use reverse spherification.
Restaurant DNA
How professionals do it
Modernist restaurants prepare bases a day ahead to de-aerate them, use caviar droppers to make many pearls at once, and use reverse spherification for spheres held through service.
At home
Start with mango or a non-acidic fruit juice and a syringe; precise small-scale weighing is the key.
General professional practice — not any particular restaurant’s recipe.
Food safety
- Use food-grade sodium alginate and calcium salts and weigh them precisely.
- Label and store additives away from ordinary pantry items.
- Small spheres can be a choking hazard for young children.
Practise it
No recipes on the site use this technique yet.