£1.99
campden tablets pack of 50

These can be used at the rate of six tablets dissolved in a pint of cool water as a steriliser. If added to a wine must at the rate of one or two per gallon, at least twenty four hours before the addition of the yeast, they will inhibit the growth of wild yeasts.

One tablet per gallon added to a wine at both the first and the last rackings will reduce the risk of oxidation. 

One tablet in an inch of water at the bottom of a sealed glass bottle or demijohn will keep it fresh for months whilst it is not in use. 

And adding one to a bucket, with a loosely fitting lid, containing five gallons of water will remove all chlorine in the water overnight. Anyone who has been unfortunate enough to suffer from TCP in a beer will know how important this can be.