What Is Gasohol?

Maggie J. Hall

Gasohol generally refers to a mixed blend fuel containing 10% ethanol and 90% gasoline. Manufacturers create ethanol using a distillation process similar to the methods used for making drinking alcohol. Gasohol fuel has advantages that include decreased dependence on foreign oil. Its disadvantages include decreased fuel economy. The concept of alternative fuels originated in the 1970s when the United States was faced with a fuel shortage.

Sorghum can be used for the production of gasohol.
Sorghum can be used for the production of gasohol.

Consumers can determine the amount of ethanol in gasoline by finding the E number on the gas pump. E10 is gasohol, while E85 represents fuel containing 85% ethanol and 15% gasoline. Most modern vehicles accept gasohol without requiring engine or fuel system modifications. Manufacturers claim that vehicles made between 2001 and 2006 may use fuel mixtures containing up to 15% ethanol. Only mixed fuel vehicles run on fuel composed of more than 15% ethanol.

Sugar cane is used in the production of ethanol.
Sugar cane is used in the production of ethanol.

Distilleries make the ethanol from sugar or starch foodstuffs that are traditionally used to feed livestock. Though corn, Jerusalem artichokes, sorghum, and sugar cane might also be used in processing. Distilleries might use sugar beets or wheat as well. The quality of the crop does not affect the final product, allowing farmers the opportunity to sell inferior or spoiled produce. In order to reduce crop production costs, researchers developed ways of using grasses, paper, and wood to make methanol, which can also be a fuel component and burns like ethanol.

Many cars run on a blend of gasoline and ethanol.
Many cars run on a blend of gasoline and ethanol.

The first step in manufacturing gasohol is making the anhydrous ethanol, meaning ethanol with no water. The crop initially undergoes a mashing process, which releases the sugar or starch. Distillers ferment the mash using bacteria or yeast, which converts the sugars or starches into ethanol and carbon dioxide. Heating the fermented mixture to 178 degrees Fahrenheit (80 degrees Celsius) causes the ethanol to evaporate. It escapes the enclosed vat in the form of steam through tubing. Cooling the tubing, converts the steam back into a liquid.

Distilleries may use sugar beets to produce the ethanol that becomes gasohol.
Distilleries may use sugar beets to produce the ethanol that becomes gasohol.

The liquid now contains ethanol and water. Through further distillation, manufacturers produce a substance consisting of at least 95.6% alcohol. One part ethanol is mixed with nine parts gasoline, a product with an octane level two to four points higher than regular gasoline, which prevents engine knocks. Gasohol burns more efficiently and completely than gasoline, leaving behind fewer tail pipe emissions.

Though internal combustion engines can run on gasohol, the mixed fuel is not without dangers. Studies indicate that gasohol eventually corrodes the metal in engines and gas tanks and causes the plastic and rubber of the engine and fuel systems to deteriorate. Fuel injectors and fuel systems clog, and metal parts also develop varnish build-up.

Jerusalem artichokes are sometimes used to make ethanol for gasoline.
Jerusalem artichokes are sometimes used to make ethanol for gasoline.

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Discussion Comments


You are very wrong. Some people just want their emotions to rule and don't let facts get in the way of a good story. It's not that simple. Methanol and Ethanol may reduce hydrocarbons slightly, but they cause more problems than they solve.

First, in order to make the same power output, engine compression ratios need to be higher to burn alcohol based fuels. It takes almost twice the volume of alcohol fuels to make the same energy output (Horsepower) as gasoline. And no, farmers do not like it. Farm equipment is expensive. Older gasoline fuel farm vehicles were not designed for gasohol fuel mixes. The alcohols in the gasoline destroys fuel pumps, needle and seat in carburators and fuel lines and gaskets, costing farmers big money for repairs and lost productivity.

The enviromentalists don't want you to know facts. Because these new fuels require more volume for the same power output, you are actually using more and paying more, but not benefiting. How is this efficient? I have used methanol extensively in race engines, where they perform very well, only if engine and fuel systems are designed for alcohol type fuels. This is a very different than a street or farm vehicle, and most people do not understand this. I could go on, but you probably do not want to hear it. Don't take my word; research it yourself.


@healthy4life – They are probably just taking it home to fill up their lawnmowers or other yard equipment. My husband always fills a gas can with the kind without ethanol when we need gas in our mower.

He told me that it is bad for the mower to use ethanol in the gas tank. He said it can cause corrosion of some of the parts.

I'm glad that he knew this, because I would have just put the same gas I put in my car in it. Apparently, gasohol isn't good for everything!


Nearly all the gas stations around here sell gas that contains 10% ethanol. I've never seen any that have 15% ethanol gas, though.

A few of the smaller stations near my house that also serve as country stores sell gas with no ethanol in it. They seem to be proud of it in their advertisements, so I'm guessing that's because of the higher fuel economy it offers.

It seems like every time I go there, I see someone filling up a big gas can, as well as getting gas in their vehicle. This makes me wonder if they are afraid that the store won't always sell 100% gasoline, and they're stocking up.


@wavy58 – It's good for farmers, too. It must increase their profit to be able to sell spoiled crops.

I agree with you. I wish that our country could become totally independent when it comes to fuel. It would solve so many conflicts.

If cars of the early 2000s can run on fuel that is partially made from crops, maybe we will one day see cars that can run fully on ethanol. That surely would put farmers back in business in a major way!


It's good that there are fewer tail pipe emissions with gasohol. I hate breathing in the smell of muffler fumes, and I know they must be terrible for the environment, because they linger in the air and make it hard to breathe.

Gasohol really does seem like a step in the right direction. I can't wait until we can manufacture all our fuel right here in the United States.

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