Testing ethanol content of fuel
 

I've read about people here testing the alcohol content of pump fuel by mixing it with water and measuring how much alcohol gets pulled out. I just picked up a 10 ml glass graduated cylinder. I'll have to measure off one more ml so I can use it in the test. My understanding is that in this case I would add 1 ml of water, and 10 ml of gasoline and shake. The water should pull the alcohol out of the mixture, so for E10 I should have 9ml of gasoline, and 2 ml of alcohol/water mixture.

I understand the principle behind this, my only question is how long do you wait? Is it instantaneous? Do you have to wait 5 minutes, an hour, overnight?

Thanks,
Jay

i am just responding to this thread so i see my checkmark when browsing threads. i cant wait to see the results as i hate ethanol.

I found a second 10 ml glass graduated cylinder. Here's my current thoughts. I get (3) 1 gallon gas cans. When I get gas I put 1 gallon of each grade in the cans, and test it for ethanol content later when I have time. Then I will dump the can(s) in @ the next fillup, and add 1 gallon for each can to the gallons pumped in my gaslog. Even though I'm in an ethanol mandated area I will find some stations with less ethanol than others. When in areas with no ethanol mandate hopefully I can find the stations that sell ethanol free gasoline. Hopefully I can chart stations by city and date and find who on average has the least ethanol. Of course, I will share all data with everyone here.

-Jay

keep in mind that the ethanol is used to raise the octane of your gas in lieu of other octane boosters...

Still, I'd rather have ethanol free fuel if available. I'm trying to squeeze every extra MPG out of a full size V-8 4x4 pickup as possible. I have the nut behind the wheel pretty tight. I have some aero mods installed, and hard tires aired up to 70 PSI. I am now looking to the Beast's diet to see if I can squeeze more MPG out of it. So far I'm doing quite well (I think). I'm hitting the EPA highway rating driving in stop & go city traffic.

-Jay

I don't know the answer to the question. I think what I would do is check the alcohol content within a few minutes then let it set for a couple hours and see if there was any difference. The only thing I can think might be a problem with leaving it overnight would be the evaporation factor, guess that wouldn't be a problem as long as you sealed the containers with something like a rubber stopper. After running your tests let us know how long to let it sit. I think I might be interested in finding the alcohol content in the fuel I am buying.

It settles out in less than 5 mins, really 2 or less from my experience with testing it. I purchased a pre marked test kit, on line, then I picked up two seperate containers, one for distiled water to carry with me that lets me fill the test tube slowly to the right level and another to insert the fuel pump knozzle to capture alittle gas to slowly fill to the gas level line in the test tube. Shake for 30 seconds or so and wait for 2 minutes and it is done. I let it sit over night but it never changed, all it did was discolor the plastic test tube at the top of the fuel line near the rubber stopper. I'm lazy now I just pour the contents of the test tube into the tank when done, Oh well a little water never hurt anyone or at least not my car.

Thanks! I was thinking of just dumping it in the tank myself... I have two 10 ml glass graduated cylinders - I won't have any discoloration problems. I was thinking about carrying a bottle of water, and either a glass or stainless steel turkey baster to suck gas out of the 1 gallon can and fill the graduated cylinder with. I was thinking that 1 or 2 ml of water in the tank would probably be absorbed by E10 anyway.

The plan was to measure 10 ml of gasoline into one graduated cylinder. Measure 1 or 2 ml of water into the second, and dump it into the gas mixture and shake.

-Jay

Are you an extremely bored engineer who is ignorant of the law that says the accurate ethanol content must be posted on the pump?