I would email WinExpert directly, as they probably have this already
done before. We all make mistakes - they are pretty good at assisting
via email. They have helped me in the past within 2 days.
http://www.winexpert.com/contact_us/

I wonder if the F-pack is just corn syrup? hmm. What was your S.G. once
you added the F-pack? As long as the yeast goes into action and not
stopped by the higher S.G. - you'll just have a more potent wine. But
you'll need to add sweetner later, I'm sure.
DAve

Dr. Richard E. Hawkins wrote:
> When starting 5 batches at once, in a moment of unclarity, I added the
> F-pack to a wineexpert white zinfandel at the very beginning. It's way to
> late to stop it from fermenting, but can I replace the sweetness with
> sugar?
>
> And if so, how much?
>
> thanks
>
> hawk