Hellow again,Ok I have two batches of Elderberry going.Both are right at 4 gallons each.The first batch is in a secondary 5 ga bucket W/ airlock.It started with a bubble every 6 sec,to one every 8 two days later.Second batch is 4 days behind the first,it is now in (2) 2-gallon pails (primary).I have a 5 gallon water bottle that I plan on racking the first batch into.This will leave me with about 1 gallon head space in my carboy.Question is,can or should I leave that much head space till the secong batch is ready to top off with up to the 5 gallon mark? Thanks for all comments........Upper