Powdered Brewers Wash (PBW)

The most active ingredient is Sodium Metasilicate, the other ingredients are phosphates and sulfates - they don't list the specifics of those two but Trisodium Phosphate and Sodium Sulfate are my guesses. While John Palmer states in his book that Percarbonate is an ingredient, I don' see anything in the MSDS that suggests it so I'm going to call it that Palmer was misinformed.

the MSDS for it - it states clearly that there is 30% Sodium Metasilicate.

Their patent claims PBW is:
1. A cleaning composition comprising:
(a.) a peroxygen compound;
(b.) no less than about 10% by weight of a silicate selected from the
group consisting of an anhydrous metasilicate, an anhydrous
sesquisilicate, and mixtures thereof; and
(c.) no less than about 3% by weight of a chelate selected from the group
consisting of a carboxylic acid and salts thereof, a phosphonic acid and
salts thereof, and mixtures thereof.