AnFI (really!)
The point about testing is that you discover problems that (closed minded) people would not envisage. test and learn
Here's a test you might be interested in;
With this mornings daily check fuel sample (after testing that all was well), I placed 1 litre of Jet A1 into an empty 2.27 litre milk container. I shook it vigourously, as you would when mixing a sports drink, for a timed 10 seconds.
Once I finished shaking the fuel in the container, I timed how long it took for the bubbles to go. After 5 seconds all the bubbles had gone.
I then added a quarter of a litre of water to the container and repeated the test, with exactly the same result.
In respect of 'foaming', what have you learnt from that?