Refueling trailer fuel quality question
I have a 300 gallon refueling trailer used to remote fuel my helicopter with 100LL Avgas. I've been operating from airport for the past 5 months so have not refueled from the trailer during that period. I keep the trailer slightly tilted toward lower draincock. I just drained about a pint into a glass jar to check quality and found it to be pristine clear blue, no visible water and a few black pieces of sediment.
I set the pint (with no cap) on a potting bench near the driveway, in full sunlight, intending to transfer it to my mower. I left it there for a couple or more hours and and came back to find it to be a cloudy greenish colour with a thick clumpy yellowish suspension at the bottom.
I'm not pumping into my copter until I know what the heck that was all about. Is it just the sunlight breaking it down in the clear glass jar or indicitive of something more sinister going on in that tank (presence of water, mold, chemical breakdown)?
It drained and appeared fine until I left that clear jar in the bright hot sun. Anyone know what happened? Is five months too long to keep the fuel?