Spherification is a spectacular cooking technique we introduced at elBulli in 2003 which enables us to prepare recipes that no-one had even imagined before. It consists of the controlled gelification of a liquid which, submerged in a bath, forms spheres. There are two kinds: Basic Spherification (which consists of submerging a liquid with Algin in a bath of Calcic) and Reverse Spherification (submerging a liquid with Gluco in a bath of Algin). These techniques can obtain spheres of different sizes: caviar, eggs, gnocchi, ravioli... In both techniques, the spheres produced can be manipulated, since they are slightly flexible. We can introduce solid elements into the spheres, which will remain in suspension in the liquid, which obtains two or more flavours in a single preparation. In Basic Spherification, with some ingredients it is necessary to use Citras to correct the acidity; in Reverse Spherification, Xantana is generally used for thickening. Spherification requires the use of specific utensils (Eines), which are included in the Kits.