Colloidal silica

Silica is an aqueous colloidal suspension of amorphous silicon dioxide (SiO2). The word is composed of gravel for silicas and Sol, a synonym of colloid together.

The silica is in the form of mutually non-crosslinked, spherical individual particles which are hydroxylated at the surface. The size of the particles is in the colloidal range and is depending on the type 5-75 nm

It was approved mid-20th century as a substitute for tannins for the beauty of wine. In oenology, it is by their reaction usually ( egg white, isinglass and casein ) used primarily for the tannin correction, and for removing other fining agents such as bentonite, activated carbon or copper sulfate in combination with gelatin or other proteins. Silica sol is able to bind mucins, which act turbidity stabilizing the wine. This binding is carried out by ion exchange between the silica sol and the gums.