SLX Denatured Alcohol vs HEET vs Green (Klean Strip) Denatured Alcohol

I think Javen is right on the money. Zelph thx for sharing your stoves, I'm new to them and I'm kind of overwhelmed at what I saw on your site.

If I'm not mistaken, a stove is an engine, converting one form of matter into energy. As such each engine design may perform differently with differing fuels. My Evernew definitely isn't designed to use high ethanol content fuels without sooting. In my mind I feel that detuning a fuel to make it work in a stove isn't the best choice unless it's your only one. It would be better to use a stove designed for a higher energy fuel then go from there.

Another thing I noticed from using Green DA is the stronger scent from combustion. It wasn't that noticeable when I used it once but for testing, I ran back to back to back tests and the collective smell was significantly stronger than what I'm used to with SLX. Perhaps it has something to do with the higher MIBK content than SLX? (Methanol via HEET is not an issue since it doesn't seem to produce much at all).

I went out and did a little testing of my own with various stoves this past weekend.

My results were very similar to James’. On SLX Denatured:

Everything had nice blue flames except the two brass Trangia burners, but Trangia puts something in the burner to make the flames that particular orangish color for safety, so that’s not a fuel or burn efficiency related issue.

The same stoves on “Green” Denatured:

A lot of yellow flames although the Trangias seem less affected, and the “Tall Boy” stove (back row, center) didn’t have any yellow in the flame.

Green denatured definitely burns hotter and tends to make yellow flames. Stoves that are more efficient to begin with and burn with a lower flame handle the “green” alcohol better.

HJ
Adventures in Stoving

What a great test! You have a nice selections of stoves there Jim.

I'm in the process of uploading my comparison between SLX and Green DA to youtube, hopefully it comes out nicely.

I actually started out with a wider variety of stoves. The stoves in the above photo were just stoves that made the first cut.

My starting line up:

I’m basically looking for efficiency and reliability. I want to consistently be able to boil 2 cups of water in a variety of conditions (calm, windy, cold, etc.) on a minimum amount of fuel.

To weed out inefficient stoves, I conducted burn duration tests. Any stove that burns through a given quantity of fuel quickly is not an efficient stove.

“Closed” jet type stoves (back row in the above photo, the two to the right) quickly fell by the way side. Closed jet type stoves require priming which requires that some of the fuel be used for the priming which winds up shooting any overall efficiency to heck. A closed jet type stove undergoing duration testing:

Priming pan in use with a closed jet stove. Note blue flames coming out of priming pan.

“Fast” stoves (ones that boil water quickly) were eliminated next. Fast typically equals inefficient. This stove is inefficient!

I then benchmarked the remaining burners against Trangia burners. If a test burner cannot outlast a Trangia burner in a duration test, then there is little chance that the burner is efficient.

I noticed the tendency of hotter stoves to burn with yellow flames when using “green” denatured alcohol. Notice in the photo above that the only test stove NOT burning with a yellow flame is the tall stove in the middle of the back row. The tall stove was also the only stove that came close to the Trangia in duration testing.

After conducting duration tests, I did boil tests.

Side burners typically were eliminated during boil tests. Side burners generally have the problem of flame spillage where flames spill up around the pot and heat is wasted. Wasted heat = inefficient.

All of the above “weed out” procedures left me with a few open top jet stoves.

The tall stove shown above did exceptionally well in both duration and boil tests. Inside a windscreen, a notably different environment than out in the open as in my duration tests, the tall stove brought water to a boil slower than my Trangia burners (generally a sign of efficiency) and held the boil for multiple minutes. Inside a windscreen, I was getting nearly 15 minute burn durations on 3/4 fl. oz. of denatured alcohol with boils occurring around 11 minutes and lasting until nearly 15 minutes. That’s pretty good.

Now, I need to “deconstruct” the tall stove that did so well. I wish I could claim the Tall Boy Top Jet (the name of the stove) as my own design, but this one comes from a stove designer here in the Los Angeles area who gave me a copy of his latest creation for testing. It did better than anything else I have including the commercially produced Trangia burners.

HJ
Adventures in Stoving

With respect to your first screen test, you may find that the interaction with the pot will skew your results. The pot will act as a barrier limiting the amount of airflow to feed the flames. Along with that, it can take some time to optimize the stove to pot distance. Finally, the windscreen design can have a significant impact on the stove perfromance. So example, some double wall stoves work great in the open but fail with a windscreen. Inside a windscreen, the ambient temperatures can go up as high as 50F-70F. Best regards – Jon

With respect to your first screen test, you may find that the interaction with the pot will skew your results. The pot will act as a barrier limiting the amount of airflow to feed the flames. Along with that, it can take some time to optimize the stove to pot distance. Finally, the windscreen design can have a significant impact on the stove perfromance. So example, some double wall stoves work great in the open but fail with a windscreen. Inside a windscreen, the ambient temperatures can go up as high as 50F-70F. Best regards – Jon

Hi, Jon,

Yes, you’re right. Stoves burn very differently when there’s a pot and a windscreen in place. The pot and windscreen generally calm a stove down quite a bit, so it’s possible that I could overlook a promising design. My description above is a little bit of an over-simplification of what I actually did. I actually did conduct boil tests (with pot and windscreen) on many of the stoves that were “cut” in the first round just to make sure I wasn’t cutting a stove inappropriately. I think I’ve been pretty thorough. By the way, all of the boil tests confirmed that my “first cut” was valid.

Thanks for keeping me honest,

HJ
Adventures in Stoving

I used to think that alcohol stoves were like universal camping tools but now I'm starting to realize that it's more of a specialty tool where you want to fit the stove-to-cookware combo to your cooking needs.

For example, while I haven't tested it "out in the field", stoves that burn a lot of fuel quickly, assuming they burn relatively clean, seem ideal for those who want shorter times to heat something up or more specifically, boil water. One that tends to burn fuel at a much slower rate would also suggest less heat energy is being produced so fuel efficiency comes at a cost of increased heating times. What used to take 3.5 minutes to bring to a boil may take 7 minutes.

Efficiency, in my feeble mind means doing more with less. A stove that uses fuel slower doesn't seem to fit that theory necessarily. While a stove's heat output could be better used if superior heating materials were used in the cookware (for example copper for titanium), since copper retains heat better, it would require less effort to maintain that heat than it would titanium. Also, since Ti resists heating more than copper would, it would require more heat energy to overcome that resistance in order to have it transfer to whatever's in your cookware (water for instance).

Everything seems to have a "this for that" tradeoff.

– A stove that burns fuel fast would suggest higher heat output so you can boil water in less time. The tradeoff is more fuel for shorter times. The caveat to this is you don't want to use it in a situation where gradual heating is involved. (i.e. cooking a full turkey at 900F in half the time is not better than cooking it slower at 450F)

– A stove that burns fuel slower would suggest lower heat output so you can keep something heated longer. The tradeoff is longer burn times at the cost of additional time to boil water. This may be the better solution for those who intend to really "cook" rather than simply boil water.

– Copper is the best heat conductor between aluminum and titanium, but at the same thickness it's also the least durable. To make it as strong as Ti, it needs to be thicker thus adding to its weight. Aluminum seems to be a decent "medium" since it's tougher than copper at the same given thickness but still a better heat conductor than titanium. The issue with aluminum is regarding health concerns regarding its reaction with your food. Even damaged anodized aluminum (which isn't easy to do) might allow exposed aluminum to come into contact with your food.

I wouldn't worry too much about the aluminum cookware for backcountry use unless you are cooking with lemon juice or something else highly acidic in an uncoated pan. You'll get an order of magnitude higher dose from taking an antacid tablet or buffered asprin…and most of the cookware used in restaurants is plain aluminum.

zelph wrote: > I have 2 stoves that will burn iso91 clean. The Super Stove with reduced pot support height and the Ring of Fire stove. Photos of these stoves have been posted on Whiteblaze.net, youtube, here on BPL and bplite.com. nobody remembers them, sniff sniff :-) I have a prototype that burns kerosene cleanly. Made that one 5 years ago, posted it on whiteblaze. Nobody is seriously interested in exotic stoves. They want what everyone else is using….alcohol or canister.

Zelph,

Stoves that burn isoproanol cleanly? Are they light weight? The search function here isn’t worth beans. Do you have any links?

HJ
Adventures in Stoving

James Nomura wrote: > I used to think that alcohol stoves were like universal camping tools but now I’m starting to realize that it’s more of a specialty tool where you want to fit the stove-to-cookware combo to your cooking needs.

Yep. Well said.

James Nomura wrote: > Efficiency, in my feeble mind means doing more with less. [emphasis added]

Exactly! Or at least doing more with the same amount. Feeble? Dude, you’re going strong!

Think about it this way: If one stove takes 1 fl. oz. of alcohol to boil two cups of water and another stove takes 1/2 fl. oz, who cares if it takes a couple more minutes to come to a boil? Just by switching stoves, I’m able to do double the number of boils with the same amount of fuel. That’s efficiency.

I want a stove that is efficient but isn’t too much of a hassle to use and isn’t so “sensitive” that the slightest misstep in how I set it up prevents a boil.

James Nomura wrote: > Everything seems to have a “this for that” tradeoff.

Yep. Welcome to backpacking. Welcome to life.

Don’t get to hassled about aluminum. The whole Alzheimers scare turned out to be just that — a scare. It’s baseless, and aluminum is pretty safe.

HJ
Adventures in Stoving

Thx for the kind remarks and nice tips Jim!

Here are the links to my video test, please bear with me as I was super tired when I made those vids.

Green Denatured Alcohol Test: http://www.youtube.com/watch?v=jF5w5GAcJL4

SLX Denatured Alcohol Test: http://www.youtube.com/watch?v=vf8z_p6nb-Q

Hi, James,

Not bad vids at all.

Assuming that your videoed tests are representative, it looks like we can conclude at least two things from the videos:
A. Green Klean Strip denatured alcohol brings water to a boil faster.
B. Regular SLX Klean Strip denatured alcohol burns more cleanly (of course there are some stoves that will burn Green DA cleanly).

If you do more tests, I’d be curious to know:
1. How long does, say, 15ml of Green denatured alcohol burn for vs. the same amount of SLX denatured?
2. What is the minimum amount of Green DA required to boil 1 cup of water vs. the minimum amount of SLX DA required?

The really important question is (to my mind) #2: what are the minimum amounts required, respectively, to bring 1 cup to a boil? If I can carry less fuel to do the same amount of work, then perhaps it’s worth it to get the Green DA. Otherwise, just stick with cheaper, generally cleaner burning SLX.

HJ
Adventures in Stoving

Jim, good comments!

My conclusions for my specific test setup:

1. Green DA burns hotter due to higher ethanol content

2. The amount of heat generated is amplified by how the stove burns fuel mixture.

3. My stove setup won't likely burn high-ethanol content fuels clean without some kind of modification.

4. SLX and Methanol fuels (yellow HEET) are more forgiving to use in a cleaner manner.

5. Methanol is the least "stink" fuel to burn, Green DA is by far the "stinkiest".

6. Resorting to using water to tone down high ethanol fuels makes no sense when SLX or methanol fuels are readily available.

=====

Now regarding your questions, I believe I'd need to come up with a rig that can showcase those questions.

1. Obviously #1 is an issue about "time". Since the question is simple it's just a matter of measuring out the exact amounts for each DA and measure burn times. Honestly, I don't believe Green DA and SLX will vary much at all in terms of total burn times using 15ml each using the same, non-adjustable stove.

However if you're looking to use whatever information from that test to go after a more efficient burn, I'm thinking that since GDA has a higher energy content, a stove could be designed to tone down the combustion so that you can stretch the burn times versus SLX. I've seen a few stoves on youtube that are adjustable and I think those may make a better candiate to test for this.

2. #2's goal differs in that it doesn't emphasize time so much as long as you achieve a boil. This one's going to be a tougher for me. You'd have to minimize heat energy from being wasted from heating too much surrounding air around the flame source so most of it can be transferred to the pot, which should be made of the best heat conducting materials designed to absorb as much of the heat energy and incorporate something on the inside to allow it to give up heat as fast as possible.

I used to use a CPU heatsink on my old Pentium 2 made by a company called Alpha, what made it unique was it used both copper and aluminum to rid the CPU of heat very efficiently. The "hot" side was copper which likes to heat up quickly and retain heat. However a heatsink needs to get rid of it as fast as possible and copper does not do that well. Aluminum is almost the opposite, it resists heating up more than copper however it gives up its heat faster. So a pot with a solid copper bottom mated to an aluminum topside is what I'm thinking would best achieve the goals of this particular test.

NOTE: I recall reading something where Tinny from Minibulldesign hacked a Jetboil pot…

For the stove, I would forego the idea of using any stove design that requires priming as priming itself is an inefficiency.

6. Resorting to using water to tone down high ethanol fuels makes no sense when SLX or methanol fuels are readily available.

Maybe. But what if you don’t have to carry 30% of your fuel on your back? What if you get to your camp site, pull out 70% of your fuel from your pack and and get the remainder from the creek you’re camped by? 30% fuel weight savings would be really sweet.

Regarding my question 2, don’t get all wrapped up in the lowest minimum amount possible. The question is what is the difference between the amount of the two fuels (regular DA and Green DA) required. As long as you use a consistent set up, you should be able to determine the difference in the amount of fuel used between the two. Your Ti pot will do just fine for that.

priming itself is an inefficiency.

Well said and very true. Priming in and of itself is an inefficiency.

HJ
Adventures in Stoving

I believe in being able to use more efficient methods of generating heat for food/water however fuel dilution is directly impacting the efficiency of that fuel. For example in my specific test setup, using 30% less fuel would also come at the expense using additional water just to run the stove.

With cars, if you used a fuel that created a condition where your engine ran way too hot, the correct solution isn't to dilute the fuel, the engine needs to be retuned and/or altered to accomodate that fuel. Dilution IMO should be left as the last resort to make something work.

In order to use a higher energy alcohol fuel, it's my belief that it's better to use a stove that can make better use of it without dilution. I don't know how to figure this all out mathematically but since we know GDA burns much hotter than SLX for example, in order to achieve the same kind of results from using SLX, you need to reduce the flame from using GDA (burn less fuel but produce the same total heat as SLX) in order to conserve fuel.

I understand the concern for #2 however I'm sure you'd agree that for that test, the combination of fuel being used, stove design and pot material will collectively affect the results. If I chose to use Titanium pots, I'd likely have significantly different results from a person performing the same test using copper pots. Naturally certain stoves are better designed for gradual, steadier flame output than my Evernew stove so that's why I believe we would need to look at all areas and not just the stove or fuel.

I don't know how to say this other than through the use of the term "total balance". In Japan that basically means "everything has to be right and each part needs to be tuned properly to work best with each other, nothing can be out of place".

As soon as I find a decent portable copper tea/water kettle, I'd like to find out just how much boiling times vary between using titanium vs copper using the same amount of fuel. Then repeat that test to see how much fuel is needed to bring each pot to a boil simply due to the difference in materials.

I know there's quite a few people on this forum that probably did all of this many times before, I'm interested to hear what they have to share.

James,
Yeah a total balance of each cooking system is always needed. It also depends on where you intend to use it. The caldera cone or tight fitting wind screen are important parts to every burner(they work about the same.) How to let air in without disrupting the internal system? How to let exhaust gas out and capture the maximum amount of heat? How not to produce soo much heat it is wasted yet get acceptable boil times? What size pot? what material? What shape? All a matter of balancing the whole system.
So, my question is: If you had a copper pot, would you hike with it? Copper is *heavy*. Ti has the potential for being lighter, but, most pots are simply stamped a few times (or once) and it does not stamp really well…it rips. They end up thicker than needed, soo, they are almost always heavier than aluminum. Aluminum is very malliable, it stamps out easily and thinly. And they are lighter than ti pots. Ti does not conduct heat all that well. Aluminum conducts heat almost as well as copper.
For my money, I would use aluminum.
A camping buddy once said he could go camping with a couple sheets of aluminum foil. This is truely super ultralight, but he had to fiddle with forming a pot each time and eventually it leaked(around the 4th use) and it was hard to grab and pour.
Anyway, comparing a 1.4L ti pot to a 1.5L aluminum pot of about the same size, both fit into the same caldera cone, there was only about a 12 second differance between them on 10 runs. This was about just over the tollerance. But, the aluminum consistantly boiled that bit quicker (between 4 and 20 seconds.) But this was in a stable environment, no wind, same starting point for water(40F,) same ambient temp (68F,) same stove, same cone and the same height from the burner. (The height required a bit of fiddling with cotton line to get them the same because they were slightly different sizes, and the handle cut-out was a bit different.) I assumed that the handle cut-out would change things slightly and gave it the benefit of the doubt by applying a ten second tolerance for measurements, and the wind screen cutout. I defined boiling as 200F by a digital thermometer to avoid any large phase changes. I would also note that ti is not pure ti. Most pots have aluminum in them.
Roger Caffin suggested to me that because of the very thin nature of campware, the difference between ti and aluminum would be unimportant. Checking this with the above stuff, I agree. The actual difference of 2 seconds (after deducting the tollerance) was not real significant in an 8-9 minute boil. ANY wind would have changed the boil time. Any residual heat in the water, any air temp difference, any difference in fuel, etc.
For any real cooking, besides just boiling water, we loose any science, but I can burn soup in the ti pot. For trail stews, it is a mess. For frying, aluminum is FAR better. But this is subjective.
Anyway, I would be interested to hear what your results with copper are, should you decide to do this. Have fun!

James Marco, thanks for your input!

You're absolutely right, we haven't even gone into some of the more real important factors while outdoors… the environmental variables. I really like the comment about the wind affecting heating times and how a proper windscreen is needed to maximize efficiency. Copper is indeed much heavier than the other materials and probably better suited to use at home than on the trail.

My tests are done in a controlled environment, hardly realistic compared to what I'd likely see out on the trail, lol. Variances in a kitchen having 15-20 seconds between boil times may end up much closer in the field. Being in Hawaii I have some nice advantages and disadvantages compared to the rest of you. First ambient temps don't vary much, it's never "cold". Salt air is a given and it's always moderately humid. However a 2-day backpacking event would mean I'm doing laps around the island, lol. Also no access to grain alcohol making GDA one of the few products I can purchase with that much ethanol content.

James (Nomura):

Agreed. Diluting a fuel is hardly the best solution. The better solution is to get a stove that burns higher ethanol content fuel well.

As for pot material, it’s going to vary a lot person to person. Some will choose Ti, others aluminum, and yes some even stainless steel. Ideally, we’d run tests on each type of material, but that’s a lot of work. My thought is that by running tests with one material we might be able to make a statement that could be generalized to other pot materials. For example if we found that with, say, an aluminum pot we could boil 2 cups of 20C water with, say, 13 ml of GDA but it took 16ml of SLX DA, I think those results could be generalized to say that one can boil the same amount of water with less fuel when using GDA, yes? That was where I was going with my line of reasoning.

To me, understanding if GDA makes any appreciable difference in fuel requirements is a very important question for someone concerned with the amount of weight on his or her back. Knowing that we can burn cleanly or reduce boil times is also important, but to me the big issue is: How much less fuel can I carry if I use GDA?

James (Marco) wrote: > …a total balance of each cooking system is always needed. It also depends on where you intend to use it. The caldera cone or tight fitting wind screen are important parts to every burner(they work about the same.) How to let air in without disrupting the internal system? How to let exhaust gas out and capture the maximum amount of heat? How not to produce soo much heat it is wasted yet get acceptable boil times? What size pot? what material? What shape? All a matter of balancing the whole system.

Well said. Thanks also for your insights on pot material.

HJ
Adventures in Stoving

Intent: To determine boiling times of 2 cups of room temperature tap water using 3 different alcohol fuels, HEET (yellow), GDA and SLX DA.

Conditions: 78F ambient room temperature, 55% humidity, 90 feet above sea level. Water is stabilized to 75F before starting each test run. Stove will be lit and pot will be set on the DX stand immediately (before it achieves full bloom). Timer will be stopped once full rolling boiling has been achieved. The stove will then be allowed to properly cool down for 10 minutes between tests with a Vornado desk fan aiding. GDA is to be tested last due to sooting. Each fuel will be tested twice and each time will be recorded.

Pot and Stove Used: Evernew 600ml Titanium teapot (no lid used for testing), Evernew Titanium DX stand and Ti stove.

=====

Results:

HEET (yellow), 99% methanol —> 5:48 both runs

SLX (approx. 50/50 ethanol/methanol) —> 5:25 both runs

GDA (approx 90/10 ethanol/methanol) —> 5:32 both runs

=====

Hypothesis/Theories/Conclusions:

First of all I was surprised to find out that the times for each test were identical and repeatable. I'm now at the idea that repeating the same test twice is unnecessary if the test conditions are the same.

GDA's performance surprised me, despite all that has happened, I expected it to be the best performer. However thanks to many of your comments during the course of this thread, I now have a better idea of what might be going on and it was already mentioned earlier.

The theory is since GDA is burning too hot, the extra heat is being absorbed by the stove resulting in more fuel being boiled off creating an overly rich condition, and the immediate combustion area lacks sufficient oxygen to burn it off completely which leads to the sooting and reduced boiling times.

James,

Good stuff, bro! More interesting tests and interesting results. You’re a very meticulous person if you’re getting such repeatable results. Particularly outdoors it’s hard to get such repeatable results.

The theory is since GDA is burning too hot, the extra heat is being absorbed by the stove resulting in more fuel being boiled off creating an overly rich condition, and the immediate combustion area lacks sufficient oxygen to burn it off completely which leads to the sooting and reduced boiling times.

James, my take is that although the GDA has more potential heat, the GDA isn’t putting out all the heat that it might. The problem is that it’s not burning efficiently and so some of the heat is “left on the table.” We need to fully burn the GDA in order to realize all of the potential heat in GDA. I’ve got a candidate stove based on my testing from a week ago. The stove designer whose design I was testing has promised me one for further testing. More to follow when I’ve done some more tests.

HJ
Adventures in Stoving

Recently I was in discussion with a fellow stove maker and the discussion went into  Green (Klean Strip) Denatured Alcohol causing soot on the bottom of a Sterno Inferno pot with heat exchanger fins.

Looking for an update from folks out there using  Green (Klean Strip) Denatured Alcohol and soot being formed on the bottom of pots. Thank you for your imput.

https://backpackinglight.com/forums/topic/13360/

Putting water in alcohol has got to be the most counterproductive measure that minibulldesign had ever come up with. Those that continue to advocate doing so are ………

I’m looking for updates on Green(KleanStrip) Denatured alcohol causing soot not how to dilute it with water that will reduce soot.