My attempt at rum dunder

[Manc]

Hi hope someone can help so last year I did a pugi rum which went well thanks to all those that helped. I saved some of the backset for my next run after reading about infections I didn't add any goats heads or anything just the backset.

I've just left in a barrel with a lid but not airtight but I'm sure I read that if it goes moldy it's no good but can't find it now I was wondering if anyone can help

Thanks in advance
Lee