In a couple of days I plan on moving my Pear Wine to secondary. Due to the large amount of pulp and a bit of overflow there is going to be a fair bit of air at the top of the demi-john. I realise that it can be quite nasty (eg introducing bacteria etc) having a large air space so I assume this needs topped up.
Whats the best thing to top it up with? I doubt there are many places i will be able to get pear juice locally and was wondering what the best approach would be? Should I also be adding extra sugar (already 1kg of sugar introduced at the start) if I want to retain the ABV?