# Why is E85 going down in price with gasoline? **URL:** \ **Category:** Factual Questions\ **Created:** [January 7, 2015, 1:02pm UTC](https://boards.straightdope.com/t/why-is-e85-going-down-in-price-with-gasoline/709214 "2015-01-07T13:02:26Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![FlikTheBlue](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fliktheblue/32/10972_2.png) [@FlikTheBlue](https://boards.straightdope.com/u/FlikTheBlue)\ **Post date:** [January 7, 2015, 1:02pm UTC](https://boards.straightdope.com/t/why-is-e85-going-down-in-price-with-gasoline/709214/1 "2015-01-07T13:02:26Z")
The E85 gas at my local station has remained about 20 cents cheaper than regular gas. I understand that gasoline prices are down due to the decrease in oil prices, but isn’t E85 made mostly from corn? Are corn prices also dropping, or am I missing another factor at play here? ---
**Author:** ![DrFidelius](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/drfidelius/32/3447_2.png) [@DrFidelius](https://boards.straightdope.com/u/DrFidelius)\ **Post date:** [January 7, 2015, 1:03pm UTC](https://boards.straightdope.com/t/why-is-e85-going-down-in-price-with-gasoline/709214/2 "2015-01-07T13:03:36Z")
E85 is 15% ethanol. The other 85% is gasoline. ---
**Author:** ![Silophant](https://avatars.discourse-cdn.com/v4/letter/s/a698b9/32.png) [@Silophant](https://boards.straightdope.com/u/Silophant)\ **Post date:** [January 7, 2015, 1:08pm UTC](https://boards.straightdope.com/t/why-is-e85-going-down-in-price-with-gasoline/709214/3 "2015-01-07T13:08:02Z")
[No, it isn’t.](http://en.wikipedia.org/wiki/E85) ---
**Author:** ![Alley\_Dweller](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alley_dweller/32/430_2.png) [@Alley\_Dweller](https://boards.straightdope.com/u/Alley_Dweller)\ **Post date:** [January 7, 2015, 1:12pm UTC](https://boards.straightdope.com/t/why-is-e85-going-down-in-price-with-gasoline/709214/4 "2015-01-07T13:12:08Z")
[US Department of Energy](http://www.afdc.energy.gov/fuels/ethanol_e85_specs.html): > [@](#): > > E85 Specification > > ASTM International developed a specification for gasoline-ethanol blends containing 51%-83% ethanol that address proper vehicle starting, operation, and safety in varying temperature conditions. [Also US Department of Energy](http://www.afdc.energy.gov/fuels/ethanol_e15.html): > [@](#): > > E15 > > The U.S. Environmental Protection Agency (EPA) defines E15 as gasoline blended with 10.5%-15% ethanol. In 2011, EPA approved E15 for use in conventional vehicles of model year 2001 and newer, through a Clean Air Act waiver request, based on significant testing and research. Stations are not required to sell E15. E10 remains the limit for passenger vehicles older than the 2001 model year and for other engines and vehicles that use gasoline, such as lawn mowers, motorcycles, and boats. ETA: Just like **Silophant** said! ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [January 7, 2015, 1:17pm UTC](https://boards.straightdope.com/t/why-is-e85-going-down-in-price-with-gasoline/709214/5 "2015-01-07T13:17:25Z")
Part of the reason is it does take some energy to make it, which is dependent on the price of that energy. Corn is often fertilized with petroleum derived fertilizer. The costs are sometimes more instantaneously realized as sometimes the costs of stuff used is paid for at the time of selling the product. The other part has to do with it’s value is tied to the value of gasoline as it is a direct compete product. It must be cheaper or people would in general not buy it. With less people buying it the cost of production would go up, further driving up the price. > [@DrFidelius](#): > > E85 is 15% ethanol. The other 85% is gasoline. That would be E15 ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [January 7, 2015, 1:54pm UTC](https://boards.straightdope.com/t/why-is-e85-going-down-in-price-with-gasoline/709214/6 "2015-01-07T13:54:30Z")
> [@FlikTheBlue](#): > > The E85 gas at my local station has remained about 20 cents cheaper than regular gas. Only 20 cents cheaper? That’s nowhere near economical. While your cost per tank will be cheaper, your cost per mile is going to be significantly more expensive with E85. The energy density of E85 is horrible compared to regular gasoline. ---
**Author:** ![Ethilrist](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ethilrist/32/4604_2.png) [@Ethilrist](https://boards.straightdope.com/u/Ethilrist)\ **Post date:** [January 7, 2015, 2:11pm UTC](https://boards.straightdope.com/t/why-is-e85-going-down-in-price-with-gasoline/709214/7 "2015-01-07T14:11:31Z")
Maybe the gas companies are catching on to the idea that if the stuff’s too expensive, we won’t buy as much of it? ---
**Author:** ![puddleglum](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puddleglum/32/137_2.png) [@puddleglum](https://boards.straightdope.com/u/puddleglum)\ **Post date:** [January 7, 2015, 2:35pm UTC](https://boards.straightdope.com/t/why-is-e85-going-down-in-price-with-gasoline/709214/8 "2015-01-07T14:35:11Z")
Corn prices are dropping due to a record harvest last year and expectations for another one next year. They have fallen about 42% over the last two years. ---
**Author:** ![DrFidelius](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/drfidelius/32/3447_2.png) [@DrFidelius](https://boards.straightdope.com/u/DrFidelius)\ **Post date:** [January 7, 2015, 2:46pm UTC](https://boards.straightdope.com/t/why-is-e85-going-down-in-price-with-gasoline/709214/9 "2015-01-07T14:46:15Z")
I sit corrected. Thank you all. ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [January 7, 2015, 5:00pm UTC](https://boards.straightdope.com/t/why-is-e85-going-down-in-price-with-gasoline/709214/10 "2015-01-07T17:00:03Z")
> [@Silophant](#): > > [No, it isn’t.](http://en.wikipedia.org/wiki/E85) I’m confused. Around here (FL) all the pumps say “may contain up to 10% ethanol.”\* The rest of the country is using 85% ethanol but here in sugar cane land we’re only using 10%? \*well, they used to. Now the state has repealed the ethanol requirement entirely. ---
**Author:** ![bup](https://avatars.discourse-cdn.com/v4/letter/b/6bbea6/32.png) [@bup](https://boards.straightdope.com/u/bup)\ **Post date:** [January 7, 2015, 5:01pm UTC](https://boards.straightdope.com/t/why-is-e85-going-down-in-price-with-gasoline/709214/11 "2015-01-07T17:01:54Z")
> [@Really\_Not\_All\_That\_Bright](#): > > I’m confused. Around here (FL) all the pumps say “may contain up to 10% ethanol.” The rest of the country is using 85% ethanol but here in sugar cane land we’re only using 10%? Only if the gas pump says E85. It’s a special pump, and they almost certainly don’t have it in Florida, and there’s warnings about your vehicle needing to be able to run on E85. It’s not the 87 octane stuff where it says may contain up to 10% ethanol. [Some images](https://www.google.com/search?q=e85+pump&tbm=isch&tbo=u&source=univ&sa=X&ei=ymatVPq4M4S0yAT5-oCACg&ved=0CB8QsAQ&biw=939&bih=639). You can see if there are any near you by searching for flexfuel locator. ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [January 7, 2015, 5:07pm UTC](https://boards.straightdope.com/t/why-is-e85-going-down-in-price-with-gasoline/709214/12 "2015-01-07T17:07:51Z")
Ah. No, we definitely don’t have those. Just the regular/premium/super options and maybe diesel. ---
**Author:** ![boytyperanma](https://avatars.discourse-cdn.com/v4/letter/b/4491bb/32.png) [@boytyperanma](https://boards.straightdope.com/u/boytyperanma)\ **Post date:** [January 7, 2015, 5:11pm UTC](https://boards.straightdope.com/t/why-is-e85-going-down-in-price-with-gasoline/709214/13 "2015-01-07T17:11:06Z")
> [@Really\_Not\_All\_That\_Bright](#): > > I’m confused. Around here (FL) all the pumps say “may contain up to 10% ethanol.”\* The rest of the country is using 85% ethanol but here in sugar cane land we’re only using 10%? > > \*well, they used to. Now the state has repealed the ethanol requirement entirely. That’s on the regular gas. Regular 87 octane is sometimes a mix containing up to 10% ethanol. E85 is a specific fuel and it’s typically 85% ethanol. In my area(MA) e85 is a rarity. My truck is flew fuel and I can run e85 no problem but right now it’s more expensive per gallon then the regular. On the mass pIke yesterday it was 2.36 for regular and 2.46 foe e85 ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [January 7, 2015, 5:28pm UTC](https://boards.straightdope.com/t/why-is-e85-going-down-in-price-with-gasoline/709214/14 "2015-01-07T17:28:04Z")
> [@boytyperanma](#): > > In my area(MA) e85 is a rarity. It’s pretty rare around here, too (southern PA). There’s only one station that sells it on my side of town. Most cars, even older ones, will work just fine on E15 (or E10). Once the alcohol content gets up above 50 percent or so, it can erode certain materials in older cars (some types of plastics and rubbers). Some older cars will be just fine, others may be damaged. It all depends on what materials they used. Most modern cars will run on E85. Slightly older cars may need a new computer chip to handle the different combustion properties of E85. Once the new chip is installed, you can switch back and forth between regular gasoline and E85 as much as you want (you don’t have to go back to the old chip, the new chip will run both). With really old cars, you need to adjust the fuel mixture on the carburetor, which is usually a single screw that you adjust, and if you want to go back to regular gasoline you have to adjust the carburetor’s fuel mixture back to where it was. ---
**Author:** ![zwede](https://avatars.discourse-cdn.com/v4/letter/z/ac91a4/32.png) [@zwede](https://boards.straightdope.com/u/zwede)\ **Post date:** [January 7, 2015, 7:36pm UTC](https://boards.straightdope.com/t/why-is-e85-going-down-in-price-with-gasoline/709214/15 "2015-01-07T19:36:36Z")
There is so much wrong with that post… > [@engineer\_comp\_geek](#): > > Most cars, even older ones, will work just fine on E15 (or E10). Most newer cars run ok on E10. Many manufacturers will not warranty a non flex-fuel car that has been run on E15. Older cars have problems with E10, especially collector cars that sit for extended periods. Ethanol blends phase separate when sitting, so the engine will suddenly try to burn 100% ethanol (not good). There are also issues with fuel pumps (ethanol does not lubricate), gaskets, fuel hoses etc. > [@](#): > > Most modern cars will run on E85. Only flex fuel capable cars can run E85. All other can be permanently damaged. At the very least it will throw codes which will make it fail emissions inspection. > [@](#): > > Slightly older cars may need a new computer chip to handle the different combustion properties of E85. Once the new chip is installed, you can switch back and forth between regular gasoline and E85 as much as you want E85 requires about 30% richer mixture. How will this chip do that back & forth? Flex fuel capable cars have a sensor in the tank that tells the computer how much ethanol the fuel contains. Without that sensor you can’t switch back & forth. > [@](#): > > With really old cars, you need to adjust the fuel mixture on the carburetor, which is usually a single screw that you adjust, and if you want to go back to regular gasoline you have to adjust the carburetor’s fuel mixture back to where it was. I wish, but no. That screw is the idle mixture. Fatten up the idle and it will still be piston-hole lean under load. ---
**Author:** ![48Willys](https://avatars.discourse-cdn.com/v4/letter/4/db5fbb/32.png) [@48Willys](https://boards.straightdope.com/u/48Willys)\ **Post date:** [January 7, 2015, 7:54pm UTC](https://boards.straightdope.com/t/why-is-e85-going-down-in-price-with-gasoline/709214/16 "2015-01-07T19:54:51Z")
What zwede said. DO NOT run E-85 in the older rigs! Burning holes in the pistons is BAD! Very BAD! New engine time! don’t do it!! Besides, replacing the engine is not enviromentally friendly! It does not help your wallet either.