Misc addition
Campden Tablet (Potassium Metabisulfite)
Spec sheet The maker publishes these figures for this exact product.
- Type
- Water treatment
- Added at
- water
- Form
- tablet
- Formula
- K₂S₂O₅
- Concentration
- sold as the pure compound
- Typical dose
- 1 tablet per 75 L of water
- Timing
- Crushed into the brewing water a few minutes before mashing in.
Before you use it
One tablet treats about 75 L, so a standard homebrew batch needs only a quarter to a third of one — dosing a whole tablet per 20 L is a common and needless overdose. Boiling removes chlorine but not chloramine; only a sulfite or carbon filter does that.
Description
Crushed into tap water, it destroys both chlorine and chloramine within minutes, heading off the plastic, medicinal chlorophenols they otherwise produce. The single most valuable treatment for anyone brewing on municipal water.