Sure, you can run your alcohol stove on methanol; that's what comes in a bottle of HEET. I mean it's cheap and available and all -- but it doesn't have as much heat content as ethanol. In other words, you have to carry more methanol just to do the same amount of cooking.


OK, so I can get more heat from ethanol than methanol, great, but alcohols with high ethanol content tend to be more expensive. Just how much weight can I save? In other words, Is Ethanol Worth It?

Join me on today's Adventure in Stoving as we "do the numbers" on ethanol.

HJ

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.

Kleen-strip Green Denatured Alcohol % by wt
Ethanol 90-100
Methanol <10
Methyl Isobutyl Keytone <10
Ethyl Acetate <5

HEET is 99% Methanol with 1% proprietary additive.
Ethanol has approx 1/3 more energy as methanol by weight and 18% more energy by volume.

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 a jaw-dropping 3x the cost of Methyl Hydrate (methanol 99.9%) and is NOT as readily available. See my other post in this forum for my own non-scientific testing.

Nice post! Thanks for all the MSDS info. I've seen them before, but not all nicely collected up like that.

I've been meaning to try Sunnyside for some time. It's got good high ethanol content AND is sold by the gallon. Green denatured (at least where I've seen it) is only sold by the quart, and that gets expensive.

Do you mean "ethanol has approx 1/3 more energy than methanol"?

HJ

Wiki has an Energy content table halfway down the page at wiki/Ethanol

Methanol has 17.9 MJ/L compared to 21.2 MJ/L for Ethanol.
21.2/17.9=1.18 ==> Ethanol has 18% more energy than does Methanol.

The difference between your .333 increase and the .18 theoretical (by volume) is interesting. You're getting better than theoretical improvement using less than optimum (pure Ethanol) fuel. Sunnyside should do even better.

I was using a different site: http://hypertextbook.com/facts/2003/RoxanneGarcia.shtml
http://hypertextbook.com/facts/2005/JennyHua.shtml
26.8 MJ/kg vs 20.16 MJ/kg = 1.329x the energy by weight.

Perhaps using the energy per volume is more appropriate when using ml and oz. of liquid for stove testing? In that case your figures make more sense.

Well, whether by weight or by volume, I'm not sure, but as an actual practical matter in the field, ethanol definitely has higher heat content.

If you guys get around to doing quantity boil tests (what amount is required to boil X amount of water of methanol vs. ethanol), I'd love to see your numbers. The won't be exactly the same because so much depends on the set up used and the conditions in which the test was conducted, but they should still show the general trend of being able to use an appreciably smaller amount of fuel with a high ethanol content blend.

HJ

P.S. Anyone in LA want to hook me up with reagent grade ethanol for my tests?

Do you carry everything on your back? Then weight is the relevant parameter.

If one is a backpacker, then weight is always relevant, and as the saying goes "everything weighs something."

How much is a given individual going to spend to save 2.5 ounces? Some will laugh it off, and others will think it worthwhile to go after eliminating that weight.

HJ

Hi Jim. If you had to cook under a semi-enclosed shelter, would it be better to use the ethanol blend? Less toxic? Or would it not even matter.

It's an interesting test, but we do need to be consistent in whether we're measuring energy density by weight or by volume. By weight, Ethanol energy comes out 134% of Methanol -- by volume only 118% -- that is significant.

This has been an educational thread for me. If "high ethanol content blends like Green denatured produce a little more soot", how does Sunnyside with an even higher percentage? Since "Complete combustion of ethanol forms carbon dioxide and water vapor", I'm thinking Sunnyside may burn cleaner (less soot) since it doesn't have as much other stuff in the mix. Is there an optimum blend to eliminate soot?