Can someone please explain to me, in easy to understand terms, the
relationship between bound and free SO2?

Does the bound SO2 dissipate over time and any free SO2 then start to
bind to the wine?

I ask because I have a wine which was over sulphered last year and I
have been monitoring the free and bound SO2 over the past few months.
The bound SO2 is quite high (around 80ppm) and the free is down to
below 10pmm.

I am wondering if I should add more SO2 as the free is recommended to
be at around 20-30ppm.

Any advice / help would be greatfully accepted

AB