To clarify, a manufacturers MSDS sheet states:
Sodium Metabisulphite
Composition/Information on Ingredients
Ingredient CAS No Percent Hazardous
Sodium Metabisulfite 7681-57-4 100% Yes
Sodium Bisulfite 7631-90-5 < 0.001% No
while:
Sodium Bisulphite
Composition/Information on Ingredients
Ingredient CAS No Percent Hazardous
Sodium Bisulfite 7631-90-5 58 - 99% Yes
Sodium Metabisulfite 7681-57-4 1 - 42% Yes
So if a Formula specifies Metabisulphite then you shouldn't use Bisulphite.
Ian |