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Sunday, December 18, 2011

Is Ethanol Worth It?

In the US, if you're an alcohol stove user, you probably know about HEET in the yellow bottle. "Yellow HEET" is basically methanol. It's cheap, widely available, and burns cleanly in alcohol stoves,  The downside to methanol is that it has relatively low heat content per gram compared to ethanol.  In other words, you have to carry more HEET to do the same amount of cooking that you could do with ethanol.
The yellow bottle on the left is HEET (methanol).

If you want an alcohol fuel with more heat per gram, you might use something like Klean Strip Green Denatured alcohol. Green denatured alcohol has a fairly high percentage of ethanol which, when burned, will produce more heat per gram than methanol. If you can produce more heat per gram, then you don't have to carry as many grams to do the same amount of cooking. In other words, you can shed some pack weight. The down side is that high ethanol content blends like Green denatured produce a little more soot, are a little harder to find (Home Depot carries it), and are a bit more expensive.
Klean Strip Green Denatured Alcohol, a high ethanol content alcohol blend
The question then is: Is ethanol worth it? Is it worth going to the trouble and expense to get an alcohol fuel with higher heat content?

Let's do the numbers.  Yesterday, I went and ran some tests with Green denatured and methanol.  See the appendix for details of testing conditions and parameters.
Running simultaneous tests to control testing errors.
I could consistently boil two cups of water with about 18ml of green denatured alcohol.  I could sometimes do it with 17ml, but 17ml wasn't consistent.  With 18ml, I never failed to get a boil.

With HEET (methanol), it took me 24ml of fuel to boil two cups of water.  I could sometimes get a boil with only 23ml of alcohol, but in order to guarantee a boil, I had to use 24 ml.  In other words, it took me about 6ml more fuel per two cup boil when I used methanol.
Conducting fuel quantity boil tests.
Six milliliters of alcohol weighs about 5grams.  In other words, we can save about 5 grams of weight each time we boil 2 cups of water if we use green denatured instead of HEET (methanol).  If on a trip I do a 2 cup boil in the morning and another in the evening, I'd save 10 grams (about 1/3 oz.) in weight per day.  If I take a week long trip, I'd save about 70 grams (2.5 ounces).  Of course if you boil more than 4 cups (approximately 1 liter) per day, you'd save more.  If you boil less, you'd save less.

There's the bottom line:  You'd save about 70g/2.5oz on a one week trip if you use green denatured alcohol instead of HEET (assuming you boil about 4 cups/1 liter per day).

So, is it worth it?  You tell me.  Each person needs to decide for him or herself what weight is worth cutting and what a lighter pack is worth.  Some people are "gram weenies" looking to cut every gram possible.  Some people are "ounce counters" looking to cut weight but perhaps not quite as zealously as the gram weenie crowd.  What's your style?  What amount of weight matters to you?  I can't tell you that, but at least now you can make an informed decision.

Hope that's helpful,

HJ

Appendix:  Test Conditions and Parameters
All tests discussed in this blog post were conducted at Henninger Flats near Los Angeles, CA, USA, at an elevation of about 2600 feet/790 meters.  Air pressure as measured by my Sunnto Altimeter watch was 928mBar/27.40 InHg.  Air temperature was approximately 50F/10C.  Air temperature did fluctuate during testing.  Winds were light and intermittent, but no more than about 5mph/8kph at any given time.  Water temperature was about 45F/7C.  Trail Designs 12-10 burners in a Caldera Cone windscreen/pot support (see photos above) were used for all tests.  All tests were conducted atop a wooden picnic table in an unsheltered location.  All tests were run multiple times to preclude testing errors. Stoves, pots, and windscreens were allowed to cool subsequent to each test and had returned to ambient temperature prior to further testing.

If you look closely at the photos above, you'll see that I used slightly different versions of the Caldera Cone set up for my tests.  Simultaneous tests were run one fuel at a time.  In other words, both burners were run on the same fuel as I ran my tests.  Interestingly, even though the pot sizes are different between the two versions of the Caldera Cone I used, the amount of fuel required was remarkably consistent, both with HEET and with green denatured alcohol.
The view from Henninger Flats on Satuday, 17 DEC 2011.  Can you see downtown Los Angeles?  The Pacific Ocean?
Click to enlarge

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19 comments:

  1. I have a gallon can of Sunnyside Denatured Alcohol. It says on the side of the can: "Denatured Alcohol with less than 4% Methanol".

    Commercial Ethanol should be about 95% Ethanol and 5% water. I believe that is called an azeotropic mixture, where fractional distillation will no longer raise the alcohol concentration. We made asolute ethanol back in analytical chemistry class by mixing quicklime with the alcohol to absorb the water. You have to have absolute alcohol to mix with gasoline or the water may separate. I would assume that there is no water in HEET, since it is intended to remove water from gasoline, but I don't know that for certain. My Denatured Alcohol should then be about 91% Ethanol, 4% Methanol and 5% Water. Yours could be different. We could try a hydrometer, but it's probably not worth the trouble. In the long run, I guess that it's a question of what does it take to get the job done and if it takes 1-1/2 times the volume of HEET to do the same job as Ethanol, then the Ethanol can cost 1-1/2 times the cost of HEET, neglecting wasted volume and weight. I haven't priced any of this lately, so I will have to compare prices. Being winter, there may be some some justification for blending. I think that it's pretty clear that Ethanol is the weight and volume winner. Aside from heat value, there may be some differences in the flame temperatures that could be important in the differences between the fuels. The actual composition of HEET may not be 100% Methanol. I happen to have some Racing Fuel which should be at least 95% Methanol. It's used as antifreeze in ground source heat pump loops. I might try some of that against HEET and see if there is a difference. I's all pretty much academic, since I'll probably keep using my Denatured Alcohol. Thanks for the thought provoking post.

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  2. Sunnyside Denatured Alcohol MSDS: % by wt
    Ethyl Acetate 1
    Ethyl Alcohol 85.7
    Solvent Naptha 0.8
    Methyl Isobutyl Keytone 1.9
    Methyl Alcohol 3.6
    This adds up to 93% so I assume the remaining % is water.

    Kleeenstrip SLX Denatured Alcohol MSDS: % by wt
    Ethyl Alcohol 45-50
    Methanol 45-50
    Methyl Isobutyl Keytone 1-4
    Amount of water content is unknown and not able to compute from the above data.

    HEET is 99% Methanol with 1% proprietary additive.
    Ethanol has approx 1/3 as much energy as methanol.

    I've picked up a new brand of Ethanol called Bioflame at CanadianTire that has a really high ethanol content.
    Bioflame Denatured Alcohol MSDS: % by wt
    Ethanol 95
    Propanol-2 5
    Water content not stated.

    Jim is so right -- if you need to count grams then ethanol is the winner but it is definitely more expensive. In my case Bioflame is 4x the cost of Methyl Hydrate (methanol 99.9%) and is NOT as readily available.

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  3. Opps wrong version of Kleen-strip was quoted above, the correct one is
    Kleen-strip Green Denatured Alcohol % by wt
    Ethanol 90-100
    Methanol <10
    Methyl Isobutyl Keytone <10
    Ethyl Acetate <5

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  4. I am kind of surprised at the use of MIBK. I wonder if it is being used as a solvent for shellac rather than as primarily a denaturant.

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  5. Roarmeister and Bill,

    Thanks for all the good discussion. Roarmeister, thank you in particular for collecting up all the MSDS data.

    I really need to try Sunnyside brand. I've been meaning to for some time anyway since it has high ethanol content and is sold by the gallon. Green denatured is only sold by the quart and is comparatively expensive. I'm also intrigued that Sunnyside contains Naptha although it sounds like it's in such a low concentration that it wouldn't make much difference.

    Bill, I have no idea as to why MIBK is included. It sounds like you may have more insight on this issue than I do.

    HJ

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  6. The soot problem with ethanol is enough to kill my interest for using it regularly. In Norway it is a lot of regulations making methanol almost impossible to get. Still by my experience some methanol in the ethanol makes the soot disappear. The energy content is still much lower than in e.g.kerosene so if weight is an issue, you will need less total weight on a summer-trip longer than 5 days, or a winter trip of more than 3 days.

    Its fun experimenting with this, but I will still bring an Optimus or Coleman stove on real trips.

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  7. I am definitely going to try adding some methanol. What % did you find effective?

    HJ

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  8. I got to the home store this afternoon and found Sunnyside Denatured Alcohol at $14.00 per gallon. That works out to about 10.9 cents per fluid ounce. I also found HEET in a four pack of 12 Fl. Oz. bottles on sale for $4.00. That works out to 8.33 cents per fluid ounce. Since it tales 1.5 fluid ounces of HEET to do the same job as one ounce of Ethanol, the effective price is 12.5 cents per 1.5 Fl. Oz. By this method, Ethanol is indeed more economical, but not by much. I really do think that a blend of HEET and Denatured Alcohol may give the best performance, but at what percentage?

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  9. Another interesting thing: In straight chain hydrocarbons, the energy per unit of weight is greatest in the lighter hydrocarbons, but the energy per unit of volume is greater in the heavier hydrocarbons. Methane has the highest heat value by weight. Gasoline is lower and Kerosene lower still. On a volume basis, Kerosene is highest, Gasoline lower and Methane lower still. This doesn't seem to be quite the case with alcohols, but I haven't looked that closely at them.

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  10. Hi, Bill,

    That's a good price on Sunnyside. Usually I expect to pay $16.00/gallon. Do you mind if I ask what store that was at?

    I see you're calling for a ratio of 1:1.5. In my testing I was getting a ratio of 1:1.3. Does the higher ethanol content of Sunnyside account for this difference?

    HJ

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  11. How much methanol? 20% works always, 10 % seems to be to little. I t may wary, i dont know why. Differnces in the humidity, and the denaturation additives in the alkohol??

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  12. Yes, the denaturing agents will probably have an impact on combustion, so it would make sense that variations in the formulation of the denatured alcohol would more or less methanol, depending on the nature of the variation. Those are good numbers, though. They give me a range to experiment within. Thank you for that.

    HJ

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  13. I bought my HEET and Denatured Alcohol at Menard's. I don't know if they have stores outside of the Midwest. The 1.5:1 ratio came from your data of 18mL Ethanol doing the same amount of heating as 24mL HEET. It's just an approximation anyway.

    If the Denatured Alcohol that I get is 4% Methanol, then 10 to 15% HEET should give a good mix.

    I used to keep HEET around all the time, but since most of the fuel that we get is 10% Ethanol, it's hardly necessary anymore. I do use shellac and varnish occasionally, so normally keep some denatured alcohol for thinner and removing old finishes.

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  14. Hi, Bill,

    Thanks. Yeah, no Menards around here. :( Nice prices for you, though.

    It is surprising in a way that HEET is still on the market since gasoline has so much ethanol in it now, but since it's there, I use it. It's cheap enough anyway.

    HJ

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  15. Oh, and you're right about the ratio. 1.5:1 is a good approximation. I obviously was having a senior moment there.

    HJ

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  16. Here is a link to an interesting, but different, alcohol burner.

    http://kepisbushcraft.blogspot.com/2011/12/monkey-boy-burner-for-crusader-cooker.html

    I don't know how practical or efficient it would be. One of these could probably be adapted to a Trangia 27, but I don't have any idea whether it would be worth doing. I'm not certain thet the Vaseline tins are available here.

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  17. Bill,

    Looks like an interesting one. I doubt that exact tin is available in the US, but I'm sure that there must be something like it available. I have no idea if it's efficient or not. Let me know if you experiment with it.

    Regards,

    HJ

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  18. Try SLX denatured alcohol for winter or when low smoke is necessary. It's half ethanol half methanol so you get the best of both.

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