ethanol gas

*I’ve been doing some interesting experiments with ethanol vs no-ethanol gas. Anybody interested?



In addition to the obvious questions about energy yield per gallon and byproducts of burning (e.g. deposits or fumes), as we’re moving into hurricane season, I’m interested in whether ethanol-free gasoline has better or worse characteristics for long term storage.



*Well, I noticed that all the “contains X% ethanol” signs started disappearing from all the gas pumps around here so I started looking into it (I have some old cars, and older gasoline-powered small engine equipment whose user manuals say don’t use ethanol gas).

Come to find out (or so I am told), it appears the ethanol lobbyists got the states to remove the mandated labeling so consumers can no longer avoid ethanol if they want.

After a little research, I came across a few articles about how a consumer can test gasoline for ethanol.

I was skeptical, but since it was easy enough to do, I started doing some tests.

All it takes is some water-based concentrated food coloring.

I put some putative ethanol-free gasoline1 in a small clear container, added one drop of blue food color, and stirred it.

The food coloring did not dissolve in the gas. It formed a temporary emulsion, but then the food coloring quickly settled out on the bottom.

Then I put some 10% ethanol gasoline2 in a small clear container, added one drop of blue food color, and stirred it. The whole thing turned blue and stayed blue.

The theory behind this is that since water is soluble in ethanol, and ethanol is soluble in gasoline, the water-based food coloring will dissolve in the ethanol and remain in solution.

But the water-based food coloring is not soluble in pure gasoline, so it may form a temporary emulsion (not solution), but will then settle out.

1I searched the internet to find a place that sells ethanol-free gasoline. I had to drive 15 miles to the neighboring city to buy it. The pump was clearly and proudly labeled “NO ETHANOL” in capital letters.

2I found a local station that hadn’t removed the “contains ethanol” signs yet.

There is definitely some funky state-to-state rules here. Where I grew up (Maine) there are no gas stations that advertise ethanol free gas. Here in Washington state, they are all over the place (including one six blocks away from my house).

Now just don’t mistake your blue gasoline for 100LL! ::safety::

Well some states required all gasoline sold in their state for use in land based motor vehicles to contain a minimum percentage of ethanol. Others like OR allow only premium to be available as straight gas and they go so far as to make it only legal in vehicles that are over 25 years old. In our state they only require that an average of 2% ethanol content which allows the ethanol free gas to be sold. However it is hard to find in most cases and then the only thing you can typically get is a mid grade which is the stuff they make premium E10 out of.

That is because WA and OR are tied together by a common pipeline distribution system. So once they had to accommodate OR the refineries in WA switched to making mainly 85 and 89 octane that once blended with 10% ethanol gives the standard 87 and 91 octane at the pump. The one consistent source for all grades of ethanol free gas in WA are the Cenex stations since their fuel is delivered purely by truck from their refinery in Montana.

Prior to the OR law for the most part you only found E10 in the Seattle metro non-compliance area.

Marinas are good sources for ethanol free gas. It will be mid grade and a little more expensive but beats rebuilding carburetors.

Interesting! I hadn’t heard of this method for testing for ethanol in gasoline before. I’ll give it a try soon.

I’m lucky that my nearest gas station (farm co-op) has 2 grades of non-ethanol gas for my Harley and lawn equipment. Otherwise, I look up stations at to find other stations that sells gas without ethanol. Just make sure to note the date of the last update of whatever station you’re looking at.

I do like the test method that Ether tried. :cool:

You can test for Ethanol and actually check the % with plain water and a graduated cylinder or other method that you can measure the volume. Water and gas do not mix but water and alcohol do. When you do the water based food coloring or any water in a small amount the 3 items will mix but once the water content gets high enough the alcohol and water will separate. So put say 50ml of gas and add 10ml of water. If it is pure gas then it will go straight to the bottom and you will see the line between the two at that 10ml line. However put it in E10 and you’ll see the line at the ~15ml mark. Note that the gas that is left floating on top is not a good substitute for getting pure gas. The gas that has separated will be of a lower octane and lack the minimum mandated detergency properties.