Oak barrel storing when not in use

[Boggis Co.]

Potassium or sodium metabisulphite can be used at 1tsp in 5 litres.
If you want to release the sulphur gas quicker add half a teaspoon of citric acid to this mix. With the citric acid in, it is much faster acting, but will not keep.

Or make a 10% solution - 10g in 990 ml water. but that is proper strong IMO.

Generally I think that Campden tablets are one to the gallon. I have a bottle if you want some !!

How much Oxy-San ? dunno never used it.

thanks very much , I have some campden tablets on there way but thanks anyway