Spherification is the culinary process of shaping a liquid into spheres which visually and texturally resemble caviar. The technique was originally discovered by Unilever in the 1950s (Potter 2010, p. 305) and brought to the modernist cuisine by the creative team at elBulli under the direction of executive chef Ferran Adrià.
There are two main methods for creating such spheres, which differ based on the calcium content in the product to be spherified. For substances containing no calcium, the liquid is mixed with sodium alginate, and dripped into a cold solution of calcium chloride or calcium carbonate. Reverse spherification, for use with substances which contain calcium or have high acid/alcohol content, requires dripping the substance (containing calcium lactate or calcium lactate gluconate) into an alginate bath. A more recent technique is frozen reverse spherification, which involves pre-freezing spheres containing calcium lactate gluconate and then submerging them in a sodium alginate bath. All three methods give the same result: a sphere of liquid held by a thin gel membrane, texturally similar to caviar.