Hey Vince,
I've been bulk buying fuel for decades. Keep the jugs in the shipping cases or OUT OF SUNLIGHT. I've always kept mine in my basement and never had problems even after several years; this includes fuels with castor oil in them, though I stopped using castor almost 20 years ago...at least in my fuel . Sunlight (UV radiation) degrades fuel (and everything else) and exposure to temperature extremes will cause castor oil to semi-solidify (white flakes). High temps will expand fuel jugs and as they contract in cooler temperatures moist air can be introduced into the jug - another no-no. I'm finishing off the last of the 128 gallons I bought 3 years ago and it runs exactly the same as the first gallons.
Happy flying,
Will