Spherification — the encapsulation of a liquid in a thin, gel membrane to produce a sphere that bursts with flavour on contact — was developed by Ferran Adrià at El Bulli using two chemical components: sodium alginate (from brown seaweed — forms gels in the presence of calcium) and calcium chloride (provides the calcium ions that trigger alginate gelation). The system produces a sphere with a thin solid membrane and a completely liquid interior. Two versions address different ingredient constraints.
**Basic spherification:** - Sodium alginate dissolved in the liquid to be spherified (1g alginate per 100ml liquid). - This alginate-liquid is dropped into a bath of calcium chloride solution (0.5% solution). - The calcium ions in the bath immediately react with the alginate at the droplet's surface — forming a thin gel membrane. - Limitation: the spherification continues indefinitely — the sphere's membrane continues to thicken as long as it remains in the calcium bath, and eventually the entire sphere gels solid. - Application: for immediate service (the sphere is removed from the bath after 60–90 seconds and served). **Reverse spherification:** - The liquid to be spherified contains calcium (or calcium lactate is added — 1% solution). - The setting bath contains sodium alginate (0.5% solution). - The calcium in the liquid reacts with the alginate in the bath from the outside of the droplet inward. - Key advantage: the gelation stops when the sphere is removed from the bath — the sphere retains a liquid interior and a thin gel membrane indefinitely. - Application: for service later (the sphere is held in a water bath and served when needed). **The ingredients:** - The ingredient being spherified must be free of competing calcium or alginate interactions. High-calcium liquids (dairy) interfere with basic spherification (the alginate pre-gels). High-acidity liquids (citrus) require higher alginate concentrations. [VERIFY] Modernist Cuisine's specific formulation ranges. Decisive moment: The timing of removal from the bath in basic spherification. At 60 seconds: a thin, flexible membrane with a completely liquid interior. At 90 seconds: the membrane is slightly thicker, more stable. At 3 minutes: the membrane continues thickening.
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