Thinning stove alcohol with water

Since I get almost no soot using denatured alcohol (S-L-X from Home Depot or Lowe's) I only dilute when I need to simmer. If I'm just boiling water, I don't bother. Diluting appears to drop the temp and allow it to cook a bit longer. Some forms of rice require 20-30 minutes of cook time. Since I've started with "cozy cooking", I've not had much need for the longer cook times and save the fuel, allowing the food to rest in the insulated cozy for a while instead of cooking the whole time.

"When I started using my Trangia, I learned that one should thin the alcohol with around 10% of water, to avoid soot on the pots."

I did likewise with my meths Sigg stove (a more expensive clone of the Trangia), but it seems to not be well-known as a practice in countries that never traditionally had much Trangia use.

I've been posting on it for years but people seem to just ignore the advice.

I could be wrong here, but I was under the impression that diluting alochol with water was a typical practice in the UK because the alcohol sold there is dyed purple, and the dye causes soot unless it's diluted.

Here in the US, the denatured alcohol available in hardware stores is not dyed and burns cleaner, so I don't think there's a need to dilute it. At least not if you dilute it to avoid soot. If you dilute it in order to generate longer simmer times, I think that's a different story.

Am I off on this?

I'm no sure of the reasons, but the alcohol we get down this way doesn't burn as well in some stoves unless it's thinned. Thanks to Arapiles for that tip. However, I have been testing stoves with pure lab grade methanol as well as the purple stuff, and they both burn better with some water dilution, which leads me to wonder if the US HEAT is already watered down a little?? Anyone in the US with access to 100% pure methanol care to test it side-by-side with HEAT??

HEAT is specifically for absorbing water in gasoline systems.
It's job is to find water, bind, and burn.

Adding water to alcohol fuels does NOT improve performance it actually REDUCES the performance of it as a stove fuel more so in Methanol/water mixes than Ethanol/water mixes. I have not tested IPA water mixes.

Heet is 99% methanol, Iso-Heet is 99% IPA.

US Denatured Alcohol mixes depends on brand, the composition of them can vary quite considerably, they can contain from 20%-95% ethanol and 5%-75% Methanol with up to 10% IPA, up to 10% Methyl Isobutyl Ketone, water and many other additives I have found 13 different additives so far.

Australian Denatured (Methylated Spirits) much more consistent as it is usually 95%-96% ethanol with a water/methanol mostly making up the rest. I have not researched what is available in the UK and NZ.

As far as water added to alcohol stopping soot depositing on the pot I have not seen any evidence of this, besides a blackened pot can help the efficiency of the stove/pot system.

Tony

Thanks for that info Tony. I didn't know OZ/NZ meths was mostly ethanol. That explains why it doesn't burn as well in some stoves that were developed with methanol in mind. This will be worth knowing for folks such as Bill Bellowe and his white box stove, which those of us down-under seem to have trouble with using our purple ethanol-based fuel.

Still, there is absolutely no doubt that adding 5-10% water to methylated spirits 'improves' the flame, ie it burns more blue, less yellow flare, less soot in some of the pressurised stoves I've tested (particularly the White Box).

Hi Allison,

I have just completed an extensive series of tests with different alcohols and mixes using many different alcohol stove designs. With all of the stoves Ethanol had a slightly more yellow flame then they did with methanol including the Trangia. I will agree that Methanol burns with nice looking blue flame but that does not mean that it is a better flame, do not forget that Methanol and its fumes from combustion are very toxic.

With all stoves I used considerably less fuel to boil the same amount of water with Ethanol than Methanol, in some stoves IPA which has more heating energy than ethanol did not burn that well as when using ethanol and I used a little bit more fuel to boil but was still much less than when using Methanol. IPA had by far the dirtiest flame it also left a very powdery film on the pot, it was also the smelliest. In the Trangia IPA was the best performing fuel.

Basically I do not care if my pots get a little bit dirty using Ethanol, using less fuel is more important to me.

Tony

I know ethanol theoretically has more potential BTUs per gram than methanol, and in general all of my alky stoves burn really well with the ethanol based methylated spirits. For some unexplainable reason though, the White Box stove doesn't work well with this mix, and I get better fuel mileage with methanol in this stove, or watered down ethanol. There is no 'scientific' reason I can think of why this would be so. I know Franco and Roger Caffin have also had probs with methylated spirits in this stove, and I have tried 3 different White Box stoves now, so I know it's not just an occassional defective stove. I haven't communicated this to Bill Bellowe yet, but I think anyone down-under who is looking at getting a White Box stove should be informed that "meths" may not burn well in it.

Hi Allison,

Thanks for that information. I have not tested the White Box stove, I have tested similar designed stoves and they have been consistent with what I have found with all other alcohol stoves.

I would be interested in testing an actual White Box stove, if someone wants to send me a White Box stove or an alternative is to send me some specifications like height. out side diameter, number of hole, size of holes, distance of holes from top and some pictures of what is done inside I will make a copy and do some test, I will then post the results.

Tony

I must admit I was told to dilute meths with water for efficiency, but the Trangia site says it's to avoid sooting … which I have to say I don't care much about.

Tony

I'm pretty sure, after another round of tests this morning, that the White Box Stove in particular is sensitive to which fuel is used in it. It burns great on methanol, not so great with ethanol or methylated spirits. As I've mentioned before, I haven't seen this with other stoves of 'similar' design, such as the Gram Weenie PRO (smaller version of White Box from what I can tell comparing them side-by-side), or other pressurised stoves from softer aluminium cans.