So I've been playing with my new FeatherFire XL the last couple days, and have come up with a few questions and observations.

Everclear is only available at 75.5% in Michigan, not 95%. I used ~22ml to boil a pint of tap water with the stove throttled way down (in my kitchen). With the stove fully opened I then boiled a pint (after whole system had throroughly cooled) using ~18ml of 75% Everclear. My Ti-Tri is on the way... but still, I expected better fuel economy with the stove "simmer" setting. Any insight?

Second question: I've found mention that even pure grain alcohol (ethanol/ethyl alcohol/etc) releases formaldehyde in combustion. Is that true? If so, is there a fuel that doesn't release toxins when you burn it? By extension, I have access to 2 kinds of industrial ethanol, one of which is spectroscopic, totally pure unadulterated (though still petrochemically based, I think?) 199.99 proof. Would burning ~100% etoh be roughly 25% more fuel efficient than burning my 75% everclear? And further, even though that spectroscopic stuff is probably petrol based, would it ultimately release any more toxins than the everclear?

Thanks!

> Would burning ~100% etoh be roughly 25% more fuel efficient than burning my 75% everclear?

Weight for weight it should be more efficient. But we have found that the size of the flame and the size of the pot can be confounding factors here as well.

I think an article on water/alcohol blends is in preparation, but it is some months away.

Cheers

My experience echos Roger's comments. Even though 100% ethanol SHOULD have more energy in it than methanol, and 100% SHOULD be 33% more efficient than 75%, I find it doesn't burn as well when used straight. Watering it down does help some, but not sure just how much water is optimal. Methanol is so cheap that it's a moot point for me.

Not sure about the toxins. Incomplete combustion would, at the very least, release ethaonl fumes which are definitely a toxin. I presume CO would also be floating around?

Edited by retropump on 01/21/2009 12:26:15 MST.

Be sweet if you could water it down with cola.

Hmmm, dehydrated cola?

I can get the 190 proof Everclear here. I hike it in as a beverage. I figure in a pintch I can use it for fuel. I've never tried it in a stove. For one thing it's expensive for fuel. On another note, I don't think I could bring myself to just burning it. If it brought it for fuel I'd likely end up drinking all of my fuel and eating cold meals.

I think you are correct on the 99.99 percent stuff. They add some nasty chemicals to it in order to extract the last 5 percent of water.

I hope someone invents powdered cola soon. Hopefully it comes with powdered fizz and powdered ice.

Once again, I have posted a comment which added nothing to the conversation.

Thanks so far, guys-
I guess even if I carried the ~100%, I could water it down with water in camp and save a little fuel weight that way.

I'm not so sure about the powdered cola, but I have seen powdered beer... use a straw for bubbles?

If anyone has some insight on products of combustion I'd really appreciate it. Cheers-

A professor of mine in my chemical engineering course work said that benzene (a carcinogen) was used to extract the last bit of water to make ~100% ethanol leaving trace amounts behind. I don't think there would be any health issue using this for burning if you can get ahold of it but for drinking it's not a good idea.

On a side note this professor was telling how he was in charge of purchasing the alcohol for the parties at his dorm when he was in college in the 50's. He didn't know better at the time and purchased 50 gallon drums of industrial 100% ethanol and they mixed it with punch. He's currently over 80 and seems to be in good shape so I wouldn't get too terribly worried about it.

"I can get the 190 proof Everclear here. I hike it in as a beverage."

That's not a beverage, that's a drug. A beverage should at least taste nice ;)

RE: drinking 99.99% ethanol, bad idea thanks to the traces of benzene. Better to go with the 95% stuff. I find ethanol leaves some soot behind that I don't get with methanol, and the 95% stuff doesn't burn as efficiently as methanol in my experience, but the difference is pretty small.

I tried burning 151 proof (75.5%) Everclear in various stoves. It didn" work as well as the denatured alcohol from the paint store.

Hi Lynn

> ethanol fumes which are definitely a toxin.
Yeah, so no sniffing your cognac!
Methanol is toxic in that sense; ethanol is ... well ... not so toxic :-)

> I presume CO would also be floating around?
Some. See the alcohol section of the CO series at
http://www.backpackinglight.com/cgi-bin/backpackinglight/stoves_tents_carbon_monoxide_pt_4.html

The 95% Everclear would make a good fuel; the 75% Everclear will work in some stoves. Good fuels...

But beware: 'denatured alcohol' in the USA can legally have horrendous nasties in it. Tinny found bleach in his.

Technical Reviews on this coming soon.

Cheers

Regarding "powdered cola": try Nuun's Kona Kola - it comes in tablet form and dissolves much like AlkaSeltzer leaving a fizzy cola-ish drink. It's available next to all of the sports drink mixes in little white tubes.

Honestly, I wasn't impressed as a straight cola replacement, but it might work well for drink mixes.

Ice already comes in powdered form and can often be found on the trail if you hike in the right spots :)

Edited by slacklinejoe on 03/17/2009 16:18:50 MDT.

"Yeah, so no sniffing your cognac!"

Definitely not if you are a tea-totalling health nut.

"and the 95% stuff doesn't burn as efficiently as methanol in my experience, but the difference is pretty small."

It seems that you would get a lot less energy from burning methanol than ethanol. 2 less C-H bonds to oxidize. Do you find any noticeable difference in the field?

Hi Tom

> It seems that you would get a lot less energy from burning methanol than ethanol.
> 2 less C-H bonds to oxidize. Do you find any noticeable difference in the field?

Dead right. Technical article on this coming soon.

Cheers

" Technical article on this coming soon."

I'll be watching for that one, Roger. I'm particularly interested in the effect on combustion, if any, of the 5% of H2O that Everclear contains. Minimal, I'd guess, but I'm no expert.
Cheers,
Tom

> the effect on combustion, if any, of the 5% of H2O that Everclear contains.

That was the bit that surprised me too. A bit of water seems to be a 'good thing'.

Cheers

I've been playing with samples of ethanol and other alcohols obtained from a friend. Best stuff I've found so far was of course the stuff that we can't really get, 95% + ethanol (that grade of Everclear isn't legal in my state). A couple drops of water helped a little, but not enough to matter to me. I've been routinely using 13ml of ~95% etoh to boil a pint with my caldera cone.

"That was the bit that surprised me too. A bit of water seems to be a 'good thing'."

Would that have to do with hydrogen combustion(re-oxidation) from the fraction of H2O that dissociates as the temperature in the stove rises? My chemistry is very rusty, but I seem to vaguely recall that heat applied to water will cause it to dissociate into 2H + O. Hydrogen does not remain elemental very long in the presence of oxygen, and its re-oxidation would release heat. A partial recapture of heat released by the original oxidation of the ethanol, sort of an after burner effect? Or am I totally out in left field here?

Hi Tom

The left hand giveth, and the right hand grabbeth ...
If the water molecule dissociates it sucks energy out of the flame; when it recombines it liberates the same amount of energy. There is no net profit.

The effect of adding water seems to be more along the lines of limiting the rate of burning of the alcohol. This has two benefits I think. One is that less of the flame goes up the side of the pot to be wasted. The other is a bit more subtle, and has to do with the limited rate oxygen can diffuse into the flame from the periphery. By slowing combustion in the flame, the water prevents soot from forming so easily.

Much more in the articles.

Cheers