View Full Version : Home Made Pepsi Stoves

B Thrash
10-16-2003, 19:23
On my last section hike I noticed alot of hikers were using home made pepsi stoves. These stoves weigh only a ounce or two and the fuel (about 11 ozs) that they carried in plastic bottle with a screw cap on it would last for several days when they used about an oz for each cooking. I would like to know what would be the best type fuel to use with this stove?. i.e white gas, wood alcohol, heet or some other fuel.

10-16-2003, 19:33
SGT. Rock did a bit of a study on this somewhere. As I recall, Isopropyl alcohol throws out the most BTUs (is hottest) but burns real dirty. Ethyl alcohol (either denatured or pure grain) is next hottest and burns clean. Methyl alcohol has the least BTUs and is clean.

Methyl alcohol is cheap and can be found just about anywhere. Gasline antifreeze (HEET is a brand name) is mostly gasline antifreeze, although some supermarket brands are cut with other stuff causing some dirty burning. About $1.25 will buy you a bottle of HEET, which generally lasts (me) 8-12 days. Denatured alcohol is more expensive and a little harder to find. You generally need a hardware store or an outfitters along the trail (sell by the ounce). Most hardware stores will only sell you a liter can, which means you need to split it with someone or leave it in the hiker box (note: Check hiker boxes for fuel before buying). Pure grain alcohol is expensive (you pay alcohol tax), but you can make afternoon cocktails with it.

B Thrash
10-16-2003, 19:47
After the first cooking and a nip using pure grain alcohol I will be without fuel. Maybe I should not consider this for fuel, go with heet will be my best bet.

10-16-2003, 20:00
On a shorter trip the wise man brings denatured or methyl and a flask of rum or bourbon.

10-21-2003, 09:38
This is from (I think) Sgt Rocks study: Edited so I could type less javascript:smilie(':p')

Using the same stove to boil the same amt of water in the same covered pot, using exactly 1oz of fuel I timed minutes & seconds to a rolling boil & to flame out.
*Lab grade USP Ethyl 200 proof/dehydrated... 7m45s to boil, 9m54s to flame out.
*Paint store denatured 70%Methanol... 8m30s to boil, 10m45s to flame out
*HEET gasline antifreeze... 9m10s to boil, 10m30s to flame out
*Rubbing alcohol Isoproyl 70%. 10m30s to boil, 10m25s to flame out, I had to re-do this 1 test twice using extra fuel to get the 10m30s boil.
HEET; the red bottle is isopropyl & the yellow bottle is methanol. Isopropyl alcohol burns with yellow, sooty flames, indicating that it is not combusting completely. It is less toxic than methanol, though.

My note: "Less toxic" is relative, DO NOT DRINK EITHER, THEY WILL KILL YOU.
Also, I have never timed it, but these numbers seem to be close to what I have experienced at home AND in the field.


10-21-2003, 10:08
I use a mixture of isopropyl alcohol and denatured (methanol) alcohol. The latter is very expensive and the former is really cheap. You don't want your alcohol dry, a little water helps the furl burn better. My combination is 55% denatured, 45% isopropyl and maybe 15 water. This has worked well for me. It dependes upon how much air one gets to their flame. You doe not want a yellow flame (dirty and not as hot). Blue flame is good. You may want to increase the denatured alcohol or add a little bit of water to get to the blue flame. I carry my commercially made alcohol stove with me even when I am day hiking. Nothing like hot soup for linch on a cold day.

Grey Owl

10-21-2003, 10:31

I'm not following the water thing. Wouldn't that just dilute the mixure and make it give off less heat? Last I checked water was not flammable. However since it is the gasses burning and not the actual liquid you may have a point. Could you or someone else comment on the concept of adding water to fuel.

10-21-2003, 10:47
I used a pepsi can stove and heet on a recent hike and my problem was that it severly blackened the bottom of my pot. Someone suggested that I coat the bottom of the pot with soap to prevent blackening. Is blackening normal or did I do something wrong?

10-21-2003, 10:57
red bottle or yellow bottle Heet - it sounds like you were using isopropyl Heet (red bottle) - generally isopropyl will soot up your pot - I have tried several designs of stoves trying to use isopropyl but I have not found one that I am happy with.

10-21-2003, 11:01
I use HEET (in the yellow bottle not the red) most of the time and ive never had any soot on my pot. There must either be some impurities in the HEET you have been using or maybe there is water or something that has gotten into your stove that is causing the blackening. Was the fuel bottle you used completely clean and dried out before you put the HEET in it?? Streamweaver

10-21-2003, 11:01
I use denatured alcohol from the hardware store, purchased by the gallon it's cheap enough to not be worth spending much effort looking for cheaper sources.

I get no soot and the flames are clean blue.

Agree with HOI -- sounds like you got isopropyl or the stove wasn't getting enough oxygen (what did you use for a windscreen?). What color flames did you have?

A little soap on the bottom of a pot before cooking is an OLD trick for cooking over wood fires that I learned MANY years ago in scouts. As I remember it didn't work real well then either, it was just better/easier to cook over coals or other clean heat sources. :)

10-21-2003, 11:09
Thanks for the replies. I used the heet in the red bottle. I'll try something else. Another thing is that with these stoves there is no flame control. My stove seemed to flame up quite a bit. Also, you have to rig or make something to set your pot on. But, you can't beat the weight.

10-21-2003, 11:12
Being a chemist you think that I would know the answer to that question, but I really don't. The amount of water is very trivial, actually 95% Ethanol (which I can get in the lab) does very well. The soot thing comes from incomplete combustion of the fuel and is dependent upon the amount of oxygen present. One does not need as much alcohol to burn methonal as opposed to isopropyl alcohol. On the other hand one does not get as much heat from methanol as one can get from isopropyl alcohol. SO I go for a mixuture. The instructions that came with my stove said to use a litle bit of water if the flame is yellow.

One can cut down their boiling time if they paint the bottom of their pot black. I have a very old 2 cup aluminum pot that I used spray black enamel on. A thin coat of enamel. It decreased my boiling time by 3 minutes!!

Grey Owl

10-21-2003, 11:24
A good set of instructions can be found at;


You should cut and paste the link. Will tell you how to make a holder. My fist stove was a tuna can stove that worked very well, them I went to a pepsi can stove that was lighter. I now use a Tranga westwind stove that is still light, but rugged. Works very well.

Grey Owl

10-21-2003, 22:24
Why soap your pots?
I paint the bottom of all my pots with black grill paint which seems to speed the cooking time by a few seconds, well at least I think it do, I have never tested it actually. BTW: don't use "engine paint" as it becomes slick when heated, I learned that lesson years ago, AFTER loosing all my hot water as the pot slipped off the stove. :rolleyes:

Also, I think that the "water helps" theroy is for very hot weather, it slows the combustion down so the food cooks slower or more evenly or something. I don't know I always use fuel with as little water in it as I can.

steve hiker
11-16-2004, 03:06
I've made 3 pepsi stoves so far, and each one has its own personality. Each were built according to instructions on PCTHiker, using a Pepsico (Sierra Mist) top and Guiness Draught bottom.


First stove -- Burns with an even temper, but takes a couple of minutes for the flames to come out the pinholes on top. Boil time for 18 oz. water at room temperature (70 degrees): 7 minutes

Second stove -- The flame doesn't come through the pinholes on this one, except after about 10 minutes of burn time. Even then, the pinhole flames are small. For all intents and purposes, the flame is restricted to the open center only. Perhaps the 3 punch holes at the bottom of the inner wall aren't big enough to allow enough alcohol into the outer chamber. I'm going to take it apart and try making these holes bigger. Boil time for 18 oz. water at room temperature (70 degrees): 10 minutes

Third stove -- For this one, I lightly stuffed plain steel wool (no soap) between the outer stove wall and the interior wall, before assembling the top and bottom. The result is the alcohol is drawn up to the pinholes immediately, and it burns robustly. Boil time for 18 oz. water at room temperature (70 degrees): 5 to 6 minutes

With each stove, I've had a slight leakage problem as a result of crimpage from fitting the top (pepsico can) section over the bottom (Guiness Draught can). Even using a shimmey, there is a slight indentation on each stove that I've had to seal with JB Weld or tape.

Anyone else find each stove to have its own personality?

Dances with Mice
11-16-2004, 07:52
Anyone else find each stove to have its own personality?

Yeah, definitely. In fact, each piece of my homemade gear is unique, or has a personality as you say. Few of those items were my first attempts at making that item, and each has some feature or function that suits me better than other attempts. A lot of my store-bought gear has been modified in some way, too.

Since you're experimenting with homemade stoves, try out the cat stove (good directions on Rock's homepage) and check out my photo gallery on the "kitten stove" manufacture, it's a lightweight variation on the cat stove. It's easier to make (I think), and burns different than the pepsi-style stoves. Whether it burns better or worse depends on your preferences and, of course, the stoves' personalities.

11-16-2004, 09:50
You asked:


I'm not following the water thing. Wouldn't that just dilute the mixure and make it give off less heat? Last I checked water was not flammable. However since it is the gasses burning and not the actual liquid you may have a point. Could you or someone else comment on the concept of adding water to fuel."

I have worked in the lab for a couple of ethanol plants, and learned something about the chemistry of ethanol while there.

First, I know that when used for fuel in internal combustion engines such as in cars, ethanol mileage per volume used does increase when there is a modest amount of water in the fuel (say, 10%), as opposed to it being virtually completely anhydrous. The reason for this is that water expands well as it vaporizes and the reaction gases pushes pistons more efficiently.

Now, the situation with heating a pot by burning alcohol with or without some water in it would be a somewhat different situation. If true that a pot of water will come to a boil sooner if heated by alcohol with a little water in it(and I suspect that it would be), it would probably be due to the water's very high gram specific heat. That is a chemical term that means that a lot of energy is involved in heating or cooling a given mass (weight) of water. Steam (hot water vapor) in the fumes from an alcohol stove would be more efficient at transferring heat to a pot than would simply heated air and carbon dioxide alone. Now, there is water that is produced by burning ethyl alcohol in any event as shown by the figure below, but it makes sense to me that slightly increasing the amount of water vapor in the fumes could make the heat transfer process more efficient, thus speeding up boiling.

from http://home.att.net/~cat6a/org_chem-VIII.htm

Now, there is obviously an upper limit to the amount of water desired in with the ethanol in your stove. Aside from obviously not wanting to have to heat a whole lake's worth of water to boiling with a tiny volume of ethanol, there is also an upper limit to how much water can be mixed in with ethanol and have it still burn. I remember it was about 50%.

Just having your fuel mixture be slightly above 50% isn't acceptable, either, IMO. The reason is that during burning the alcohol will be preferentially removed (taken out at a faster rate than is the water). This is due to the alcohol having a lower boiling point than water. So, if you had a stove with fuel that was only 55% ethyl alcohol, it would probably light, but after you burned only part of the fuel, it would go out and be unrelightable, leaving water-enriched warm fuel that still had a considerable amount of alcohol in it. Much better to be initially considerably above the minimum alcohol proportion that will ignite; I can't tell you the exact percentage off the top of my head, but 90% intuits about right.

Also, ethanol absorbs water from air very readily, so keep that in mind for storage. If you keep it in mostly empty containers, it will absorb considerable water from the air. This is especially true in warmer weather (over 55o F, say), as warm air tends to carry far more water than cooler air.

Chris is also correct that isopropyl yields more heat per volume burned than does ethanol, and ethanol more than methanol. The difference is substantial, especially between ethyl and methyl. (I can give you exact numbers if you need it.)

As far as the toxicity issue goes, the difference between isopropyl and methy alcohol matters considerably IMO. Both are bad news when swallowed, but methyl is worse, and goes straight to the optic nerve; that's why moderate methyl alcohol contamination of beverage alcohol makes so many people who drink it go permanently blind. Isopropyl's vapors are no big deal to breath in moderate amounts, and we all know how it is accepted to use on skin. You do NOT want to get methyl alcohol on your skin! I don't know the exact exposure limits (look up "Material Safety Data Sheet" for methanol if you want to know; it's online), but if you just don't buy methyl alcohol, you don't have to worry about it.

Lastly, the various alcohols have different flash points, related to (but NOT the same as) their boiling points. What this means to a hiker is that a stove with isopropyl is harder to get going when it is cold than one with ethyl, and one with ethyl than one with methyl alc. The rule of thumb for ethanol was that below about 45o F. it pretty much did not give off flammable fumes. The usual way around this is to have a SMALL amount of something (usually a petroleum-derived chemical) with a much lower flash point mixed in. That is why pure ethanol is not used for vehicle fuel up north, rather it is mixed with 15% petroleum products. Alternatively, you could just put your stove near your body long enough to warm it up to above 45o, and many hikers already know to do that.

Hope all this helps. If you have any more questions, ask away; if I know the answer, I'll happily tell you.

Rain Man
11-16-2004, 10:55
... If you have any more questions, ask away; if I know the answer, I'll happily tell you.

I have one. What are the common names for these alcohols?

As in, where does "denatured" alcohol fit in your explanations (which were very fine, BTW).

Rain Man


11-16-2004, 11:39
Isopropyl alcohol = isopropanol = rubbing alcohol (normally only 70% alcohol, the rest is mainly water). This is the ~40 cents a pint bottle stuff you can get in the pharmacy section at Wal-Mart.

Ethyl alcohol = ethanol = beverage alcohol = grain alcohol.
This is the ~$2.00/bottle stuff in the pharmacy section.

Methyl alcohol = methanol = wood alcohol
(NEVER found in pharmacy section, guaranteed)

The structure of each type of alcohol comes from the related hydrocarbons:

<TABLE border=1><TBODY><TR><TD>Meth</TD><TD><CENTER>1</CENTER></TD><TD>methane</TD><TD>CH<SUB>4</SUB></TD><TD>http://web.jjay.cuny.edu/~acarpi/NSC/images/formula-methane.gif</TD></TR><TR><TD> Eth</TD><TD><CENTER>2</CENTER></TD><TD>ethane</TD><TD>C<SUB>2</SUB>H<SUB>6</SUB></TD><TD>http://web.jjay.cuny.edu/~acarpi/NSC/images/formula-ethane.gif</TD></TR><TR><TD> Prop</TD><TD><CENTER>3</CENTER></TD><TD>propane</TD><TD>C<SUB>3</SUB>H<SUB>8</SUB></TD><TD>http://web.jjay.cuny.edu/~acarpi/NSC/images/formula-propane.gif</TD></TR><TR><TD> But</TD><TD><CENTER>4</CENTER></TD><TD>butane</TD><TD>C<SUB>4</SUB>H<SUB>10</SUB></TD><TD>http://web.jjay.cuny.edu/~acarpi/NSC/images/formula-butane.gif</TD></TR><TR><TD> Pent</TD><TD><CENTER>5</CENTER></TD><TD>pentane</TD><TD>C<SUB>5</SUB>H<SUB>12</SUB></TD><TD></TD></TR><TR><TD> Hex</TD><TD><CENTER>6</CENTER></TD><TD>hexane</TD><TD>C<SUB>6</SUB>H<SUB>14</SUB></TD><TD></TD></TR><TR><TD> Hept</TD><TD><CENTER>7</CENTER></TD><TD>heptane</TD><TD>C<SUB>7</SUB>H<SUB>16</SUB></TD><TD></TD></TR><TR><TD> Oct</TD><TD><CENTER>8</CENTER></TD><TD>octane</TD><TD>C<SUB>8</SUB>H<SUB>18</SUB></TD><TD></TD></TR><TR><TD> Non</TD><TD><CENTER>9</CENTER></TD><TD>nonane</TD><TD>C<SUB>9</SUB>H<SUB>20</SUB></TD><TD></TD></TR><TR><TD> Dec</TD><TD><CENTER>10</CENTER></TD><TD>decane</TD><TD>C<SUB>10</SUB>H<SUB>22</SUB></TD><TD></TD></TR></TBODY></TABLE>
<CENTER>* only the first 4 are illustrated</CENTER><CENTER> </CENTER><CENTER>The difference between the alcohols and methane, ethane, etc. is that a hydrogen has been removed and an -OH is in its place.</CENTER><CENTER>=================================================</CENTER><CENTER> </CENTER><CENTER><TABLE width="85%" border=0><TBODY><TR><TD>Alcohol Name </TD><TD>Formula</TD></TR><TR><TD>Methyl alcohol (methanol)</TD><TD>CH<SUB>3</SUB>OH</TD></TR><TR><TD>Ethyl alcohol (ethanol)</TD><TD>CH<SUB>3</SUB>CH<SUB>2</SUB>OH</TD></TR><TR><TD>n - propyl alcohol</TD><TD>CH<SUB>3</SUB>CH<SUB>2</SUB>CH<SUB>2</SUB>OH</TD></TR><TR><TD>Isopropyl alcohol (propanol -2)</TD><TD>CH<SUB>3</SUB>CHOHCH<SUB>3</SUB></TD></TR><TR><TD>n-butyl alcohol (butanol -1)</TD><TD>CH<SUB>3</SUB>(CH<SUB>2</SUB>)<SUB>2</SUB>CH<SUB>2</SUB>OH</TD></TR><TR><TD>ethylene glycol</TD><TD>CH<SUB>2</SUB>OHCH<SUB>2</SUB>OH</TD></TR><TR><TD>glycerol


</TD></TR></TBODY></TABLE></CENTER><CENTER> This accounts for the increased amount of heat yielded per volume of alcohol burned as you raise the # of carbons in a molecule of an alcohol. The molecule has a smaller and smaller %age of oxygen; that is, it is less oxidized. Also, as the # of carbons in an alcohol increase, its other chemistry is more and more like that of the original hydrocarbon; that is, it explains why methanol and ethanol mix with water in any proportion, but the higher alcohols (butyl, etc.) not so. </CENTER><CENTER> </CENTER><CENTER>Here is a water solubility chart for some higher alcohols:</CENTER><CENTER> </CENTER><CENTER><TABLE cellSpacing=0 width="40%" border=1><TBODY><TR align=middle bgColor=#cccccc><TD align=left>Alcohol</TD><TD>(mol l<SUP>-1</SUP>)</TD><TD>(% w/w)</TD></TR><TR align=middle><TD align=left>Butanol</TD><TD>0.97</TD><TD>7.4</TD></TR><TR align=middle><TD align=left>Pentanol</TD><TD>0.25</TD><TD>2.2</TD></TR><TR align=middle><TD align=left>Hexanol</TD><TD>0.059</TD><TD>0.60</TD></TR><TR align=middle><TD align=left>Heptanol</TD><TD>0.0146</TD><TD>0.17</TD></TR><TR><TD>Octanol</TD><TD align=middle>0.0038</TD><TD align=middle>0.049</TD></TR><TR><TD>Nonanol</TD><TD align=middle>0.00097</TD><TD align=middle>0.014</TD></TR><TR><TD>Decanol</TD><TD align=middle>0.000234</TD><TD align=middle>0.0037</TD></TR></TBODY></TABLE> Octane (six carbon hydrocarbon, the main component of gasoline) only dissolves to about 200 parts per million in water, and as you see, octyl alcohol isn't that much better. </CENTER><CENTER> </CENTER><CENTER>================================================== ==</CENTER><CENTER> </CENTER><CENTER>Now, as far as the subject of denaturing goes, denaturing is something that normally is only done to ethanol. The purpose is to dissuade people from voluntarily drinking it; that is because there is a substantial tax laid upon alcohol intended for beverage use by the government, which is much larger than the cost of producing it (around a buck a gallon, or less), and the gov't doesn't want that tax to be avoided. Reagent-grade alcohol (ultrapure stuff) used in labs has had the BATF tax paid on it as part of the price the supplier charges.</CENTER><CENTER> </CENTER><CENTER>There is a huge reference book the Bureau of Alcohol, Tobacco, and Firearms puts out (I've had professional reason to consult it) that specifies what type and proportion of denaturants are to be put into alcohol, depending upon what end use is intended for that ethanol product. Ethanol intended for mixing with gasoline in a 90/10 gasoline/alc. mixture may simply use gasoline or methanol as a denaturant. Denaturants can be things like pine tar, other organic chemicals, or even bittering agents like denatonium benzoate (Bitrex). The idea is to put in something that is a real PITA to remove, and drinking the alcohol is not likely with it in it, while leaving the denatured alcohol still fully functional for its intended use.</CENTER><CENTER> </CENTER><CENTER>When you buy denatured alcohol, you are buying mostly ethyl alchol, with something (not water) intentionally added, generally in the 5% range or less. There is often water in most relatively pure alcohol sold because the last 5% or so of water is a real pain to remove from ethyl alcohol due to something called an azeotrope, and for many purposes isn't worth the effort. It is done for alcohol that will be mixed with gasoline; that typically has well under 100 ppm of water, and MUST have under 1%. I can tell you plenty more about this, but I seriously doubt you want to hear about it...:rolleyes: </CENTER>

11-16-2004, 13:28
I can tell you plenty more about this, but I seriously doubt you want to hear about it.
Actually, I thought that was a most excellent post! Very informative.

Rain Man
11-16-2004, 15:08
... There is often water in most relatively pure alcohol sold because the last 5% or so of water is a real pain to remove ...

THANKS!!! Quite informative!!!

A prior post discussed "adding" water to alcohol to make it burn better, but it would seem it all has a bit of water anyway.
Rain Man


11-16-2004, 16:32
BTW, I wrote on page 1 that octane has six carbons. That is incorrect; it has eight. Also, I think I gave the wrong impression about water vis-a-vis gasoline; they are a bad combination. If ethyl alcohol (typically added to gasoline to make gasohol at 10% volume/volume) has even one percent water, there will be a separate water-rich layer form at the bottom of the gas tank, called a phase separation. This layer will not burn when taken into the engine, an obvious drawback for a fuel. Now, when pure ethanol is used for fuel (widely done in Brazil now), some water in the multiple percent range presents little or no disadvantage; as I mentioned, it can work even better as a fuel.

You cannot just start using pure alcohol in a car engine set up to be run on gasoline; there are about half a dozen mechanical adjustments that need to be made first. You cannot use ethanol in a diesel engine at all, either.

Also, ethanol will dissolve and knock off a bunch of accumulated engine crud when you first start using it as a pure fuel (not really an issue when just replacing 10% of gasoline to make gasohol). You will go through multiple fuel filters, etc., for a while, if you switch a car over to running on pure ethanol that has been running on gasoline for a while. It is preferred to start with a brand-new vehicle if possible to run on pure ethanol, if you can. Note that no mechanical adjustments need to be made to use gasohol (10% ethanol/90% gasoline) in an engine.

About removing that last 5% of water...

Simple distillation (heat to boiling, then cool and condense) can reliably produce 190 proof (95% pure, rest = water) ethanol from fermentation mash that has gone to completion (called "beer"), which runs from several percent alcohol v/v up to about 16% alcohol (record is over 35%; sake gets over 20% by fermentation). To get it the rest of the way to suitability for use in making gasohol, a complicated device called a molecular sieve is used, which requires steam, beads of zeolites, etc., etc. The reason that pure ethanol can't be made by distillation is that azeotrope phenomenon I was referring to earlier; 99% ethanol actually boils at a lower temperature than pure ethanol does.

Had enough? ;)

11-17-2004, 10:26
If you have any inclination to use any part of what I have posted on this thread as part of a permanent piece on "Stove Issues" in the Information drop-down, feel free. I would be honored to have made such a permanent contribution to White Blaze, if you think it might be of that caliber.

SGT Rock
11-17-2004, 11:07
Actually I planned to ask you about that.Thanks.

11-17-2004, 11:15

Thanks for all the info on the fuels! Think I'll cut and paste and give it to my son. This might make a super science project!!! :)

11-17-2004, 11:30
I am genuinely glad that it looks like I have found a topic on which I can make a halfway significant contribution to White Blaze. By all means, feel free to chop up and use however whatever parts you feel would fit in to a permanent reference.

If you still have any remaining questions, do feel free to ask me if know anything about the answers. I worked in that field as my job for over four years, and learned a lot, I believe.

Bolo, I appreciate the thought, but I would caution you about one thing with science projects for pre-college school environments. They tend to be VERY much against anything that involves a flame of any kind. If they even allow such a project to be entered, it is likely to suffer prejudice that will be reflected in its appraisal.

06-10-2006, 07:27
First, I know that when used for fuel in internal combustion engines such as in cars, ethanol mileage per volume used does increase when there is a modest amount of water in the fuel (say, 10%), as opposed to it being virtually completely anhydrous. The reason for this is that water expands well as it vaporizes and the reaction gases pushes pistons more efficiently.

Not to get too far off topic here, but does this mean that an auto would actually run better, and farther if water were added to the gas tank? :confused: The stuff they are selling now has 10% ethyl alcohol blended in the gas, which means that 12.8 ounces of every gallon is alcohol. So 10% of that would be 1.28 ounces of water per gallon could be added? Or am I just all wet with this idea? :-?