Do you use sodium or potassium meta?

It could be potassium bicatbonate forming from dissolved CO2.

One benefit SO2 has that has not been mentioned is that it protect from
oxygen transfer across the airlock. That is oxygen dissolved into the
airlock water then is released on the wine side.

It is slow, but it can happen...the effect of which is probabally
negligable anyway as long as you keep your carboys topped up.


Brad wrote:
> I've used both with no ill effects what so ever from using just water.
>
> I have however noticed that if I don't change the metasulfite solution in
> the airlock in a timely manner it develops a -- how to describe it -- haze
> or something.
> I'm not sure what it is.
> I don't know if it's harmful.
> I do know that I don't like it and it makes me nervous. Can anyone tell me
> what they think it is?
>
> Brad