Sodium Silicate
The short version
Water glass — a niche anti-caking agent now largely replaced by silicates of calcium and magnesium.
It's widely considered safe at the amounts used in food, so we mark it green. The Safety section below has the details.
Where it comes from
Manufactured by reaction of sand with sodium carbonate at high temperature. The aqueous solution is the historic 'water glass' used for egg preservation (the alkaline glass coating sealed eggshells against bacterial entry).
How it's used
Largely deprecated for direct food use — replaced by the calcium and magnesium silicates (E551–E553) in modern formulations. Some niche use remains. Major non-food applications in detergents and silica-gel manufacturing.
Safety profile
ADI not specified — historically considered safe at trace residual. The deprecation reflects formulation preference rather than safety re-evaluation.
Physical & chemical properties
Colorless to slightly yellow viscous solution or white solid. Soluble in water with strongly alkaline solution.
Regulation worldwide
Permitted in the EU and US with narrow approved categories.
Educational information only. Not medical or dietary advice.