I used to make WoW by the 5 gallon bucketload until Aldi stopped doing their excellent and cheap pure white grape juice.
5 gallons is not much more effort, and lasts nearly twice as long as one gallon
Where are you getting your grape juice from? It should look a bit like a rosé when it's done.
Also, I didn't realise @Moley was a boater, but it's a familiar name from the other topic-specific forum!
Having just seen the rumours he's stopped doing wine and is making beer, maybe I should invite him to join SIBA as a homebrewing member ...