Confession - I was a professional clinical laboratory Biomedical scientist, so cleanliness must be a bit of an OCD for me.How you store low abv for that long?
Basically I do my best to keep air and hopefully any spoiling lifeforms out after the boil.
I transfer everything by pipe, first by pumping to the fermentation polypin, then pumped out to the conditioning / serving polypin casks.
If ever a tap cap is removed, and then refitted I squash all air out (resterilised cap/tap of course).
I use Metabisulphite and boiling water flushing for anything that comes into contact post boil.
I even ferment in 21L polypins connected by (sterile) pipe to a bubble trap.
The storage of finished beer is that cold dark N bottom corner of the outside garage.
Blending (mixing) is my cheapskate salvaging method when the gravity pouring of beer slows unacceptably.
Again tap to tap, short sterilised pipe by gravity and a bit of squashing.
Keep that air and bugs out!