Sodium Alginates deliver thickening or gelling functionality based on the polymer type, usage level and presence of calcium ions. When using Sodium Alginate it can be challenging to fully hydrate this cold water- soluble hydrocolloid while minimizing exposure of the polymers to soluble calcium ions. The linkages or bridges between the manuronic and guluronic acid groups and calcium ions can begin with polymer hydration and result in an uneven or pulpy gel structure that can be referred to as "pre-gelling." Often buffering salts and chelators are used to manage pH and exposure to calcium ions by selction of added calcium salts based on solubility. Temperature can be used also to aid managing the exposure of hydrated Soldium Alginate and soluble calcium and control the gel formation. It is important to remember that once gels are formed with Sodium Alginate they are not reversible. This characteristic makes Alginate a solution in bake-stable pastry fillings. Knowledge of Sodium Alginate has increased following the popularity of molecular gastronomy where it is used to make caviar-like gel beads with colorful and exotic ingredients that do not themselves form gels.