Alginate Spherification Percentage Amount Calculator

Sodium alginate spherification: percentage dosing

Spherification relies on sodium alginate (a polysaccharide pulled from brown seaweed) gelling on contact with calcium ions. Drop a flavoured liquid that contains alginate into a calcium chloride bath and a thin gel membrane wraps each drop, leaving you with “caviar” or “ravioli” spheres that still hold a liquid core. To work out how much alginate or calcium chloride you need, use mass (g) = volume (mL) × percentage (%) / 100.

Two techniques cover most of what you'll do. In direct spherification the alginate (~0.5%) goes into the flavoured liquid, which you then drop into a CaCl₂ bath (0.5–1%). The sphere keeps gelling from the outside in, so eat it quickly. With reverse spherification you add calcium lactate or gluconolactate to the flavoured liquid and drop that into an alginate bath instead. Once the sphere comes out, the membrane stops growing, which makes these far more stable. Keep the liquid's pH above 3.6, or the alginate precipitates; acidic juices need a little sodium citrate to buffer them.

Applications

Think fruit-juice caviar, mojito spheres, yoghurt or olive-oil ravioli, alcoholic pearls that burst in the mouth, and modernist plating in general. Ferran Adrià and chef Albert Adrià brought the technique to wide attention at elBulli (Spain) in the early 2000s, and it went on to become a hallmark of avant-garde gastronomy.

FAQ

Why do my spheres collapse? Usually the calcium bath is too weak (bump it up to 1% CaCl₂) or you pulled them out too soon. Give caviar 30–60 s and ravioli 2–3 min.

Can I spherify lemon juice? Yes, but first buffer it with sodium citrate (~1%) to bring the pH above 3.6. Reverse spherification with calcium lactate is the other way around the problem.

Is the CaCl₂ bath edible? In tiny amounts, yes, though it has a bitter taste. Rinse the spheres in clean water before plating.