Observing what happens to gasoline while it sits around is about as interesting as watching paint dry. But after 20 weeks, it's time to take some close-up pictures and retire a couple of samples. And some are getting hazy.
Temperature and humidity data (logged every 6 hours; average: 81 degrees F, 68% relative humidity):
But a great deal of evaporation.
The two gasoline samples (E10 and "classic") without any additives are shown below - more than half of the gas has evaporated. We'd guess the more volatile components have gone. So if your gas sits around for 4.5 months and then your equipment is hard to start.. well, now you know why, the components that help gas engines to start up easily have gone.
Here you can see that the classic gasoline has developed some haziness. E10 is still clear.
Below are the family photos of the "classic" gasoline samples. They've all evaporated significantly. No water bottoms noted. Some haziness. Although some of the samples have evaporated less than others, there could be other factors at work (not just the type of additive...for example, the specific location of the test sample). The test was not designed to compare the additives to each other, just to see what the gasoline samples did over time.
From this top view, the clarity of the classic gasoline samples can be seen. They're somewhat hazy.
Below are the family photos of the E10 gasoline samples. They've all evaporated significantly. No water bottoms (or "phase separation") noted.
From this top view, the clarity of the E10 gasoline samples can be seen.