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Comment by lenticular | Hacker News Reader

The corn lobby is very powerful. Nobody else thinks ethanol is a good idea, especially from corn (one of the worst crops you could use). The carbon inputs to make the ethanol are around the same as if you just burned petroleum in the first place. Once you burn the ethanol as well, it's much worse than just gasoline. It also encourages expansion of farm land into virgin land and increases food prices. Not to mention it is horrible for engines, especially in older vehicles.

Hilariously, gas sold for non-highway use (like farms) is not required to contain ethanol, and usually doesn't. They'll push it on all of us, but won't use it themselves.

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One reason farmers likely avoid it is that ethanol fuel only has a shelf life of about three months[1] while regular fuel can easily last a year or more. I'm sure that's an issue on a farm where fuel isn't always cycled out constantly.

[1] http://www.fuel-testers.com/expiration_of_ethanol_gas.html

That link is full of half-truths that I don't have time to address, so I'll just add your one point.

E10 is not regular gasoline with some ethanol added. E10 is a lower grade of gas with ethanol added. That lower grade of gas degrades in a few months.

Thanks for bringing up some criticisms. This past year I was stocking up fuel for emergencies and ran into fuel stabilizers and ethanol-free fuel (there's farmland nearby), but haven't done too much research into how long things should be stored, what happens, and why.

Do you have any suggestions where you find more accurate more info? This West Marine webpage seems quite a bit more reputable, a lot less alarmist, but seems to similar assertions: https://www.westmarine.com/WestAdvisor/Busting-Ethanol-Fuel-...

That page applies to boats and is seems true for boats. I might disagree that running E15 will harm fuel systems when E10 won't, but that is the only place where they are possibly wrong.

It is really hard to find unbiased sources.

From what I can tell (lots of sources, but I'm not sure where I read all this so you have to decide if you believe an admitted amateur in all this): gasoline is a mix of molecules. Some of them evaporate faster than others (read lower octane) - these are generally cheaper and some have more energy when burned. Some will break down into other molecules (air and/or water is a catalyst factor here) forming what looks like varnish and smells like turpentine. Gasoline is a mix of these (depending on temperature, cost and EPA rules).

Water is interesting. Depending on temperature you can mix up to about 5% water in gasoline, and surprisingly in a warm engine you get more power/MPG when you do this (engines won't start as well though). This was commonly done until the mid 1980s because adding water is a cheap way for a gas station to make their fuel cheaper than the competition while still claiming good fuel.

Ethanol makes things tricky. Ethanol and water mix just fine (common beer is a little ethanol and a lot of water), OR ethanol and gasoline mix well. However all three do not mix: if you mix ethanol, water and gasoline you end up with a layer of ethanol/water and a layer of gasoline. (you can mix up to .1% water with ethanol and gasoline but that is so low as to not count).

Now some simple math (meaning wrong but close enough): if you mix 1% water with E10 your ethanol layer is 10% water - this is enough water that you won't be able to start your engine, though if it is already running it would run. If you had 100% ethanol that amount of water wouldn't be a problem: the engine would run fine 1% water 99% ethanol.

Ethanol doesn't absorb water from the air. However when (not if) water condenses [temperature changes] in the fuel tank ethanol will absorb it. Thus in a humid environment where fuel is stored long ethanol will separate just from water in the air. This is often said the be ethanol absorbing water from the air but that isn't exactly what happens.

Because ethanol increases the octane rating?

> Hilariously, gas sold for non-highway use (like farms) is not required to contain ethanol, and usually doesn't

Only seven states actually require the use of E10 for non-farm gas. All the others are just using it to satisfy the corn lobby.

Also, a lot of small engines (with carbs) demand non-ethanol gasoline; apparently ethanol gums up the carbs I think.

Of course, it'd be better if we just stopped using those small engines altogether... one leaf blower being used for one day puts out as much pollution as a Ford Raptor pickup in 100,000 miles.

Ethanol does not "gum up" (note I am not defending anything here). Just open up your bathroom cabinet. I bet you got a bottle of isopropyl alcohol in there. Its probably years old too. How "gummed up" is it?

The gumming up of ethanol mixed fuels is due to the poor quality of gasoline base that is used.

The gumminess comes from degrading rubber hoses and seals, neither of which are found in a plastic bottle.

Well, it also comes from dissolving years of gasoline deposits, if you've been using non-ethanol gas before. Ethanol is a very effective cleaner.

In addition, it's hygroscopic.

That doesn't matter much in modern fuel systems that don't admit much water to begin with.

"Dry Gas" is usually just some sort of alcohol, which mixes with both water and gasoline. Add dry gas, the water mixes into the fuel and is pushed/burned off.

I buy premium gas for my small engines. They don't need the octane, but it's easier to find non-ethanol gas in premium than in regular unleaded.

There's plenty of corn in the midwest. Also Brazil is the largest ethanol producer, producing from sugar cane. I bet because of this we may see more corn this year and less soybeans due to the trade war.

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