Soto Microregulator vs. Monatauk Gnat in Cold Wx

"Jim's test is actually very good. While most quality canisters have propane and possibly isobutane instead of N-butane. there are probably some cheep brands out there that are filled mostly with just N-butane. In most cases vendors do not list the exact contents of the cans and in fact the contents of the can may very over time due to canges in the price of propane, isobutane and N-butane. When Jim filled both his canisters with butane he eliminated the biggest variable in most other reviews and test."

Thank you for that explanation.

"something something something you don't like to do your home work something something."

Stuart… when you say things like that…. it hurts my feelings….. I've sent Ryan an email asking him for an intervention where we can learn to express our feeling in a mutually beneficial way.

On a more serious note, you are correct and I need and will do more research on fuel characteristics for no other reason than to understand when issues like this are raised. I have no intention of ever mixing my own fuel or refilling a canister so I keep my personal research confined to how stove a works with fuel b. Where you are incorrect is that I invest plenty of time simulating field conditions in camp backyard so I am not hit with surprises in the field. My wife has serious concerns with my water boiling obsession.

When someone voluntarily starts a thread about a stove's field performance it isn't unreasonable to ask them about their testing methodology and why they chose to introduce certain variables, especially when the results are massively inconsistent with my experiences with this stove under similar conditions. Another person answered those questions for Jim so onwards and upwards.

FWIW I haven't seen anything with this canister north of 30* with commercially available fuel which should cause anyone alarm. We're having an unusually warm winter so not too many days below the 30s to test this stove out. For giggles I threw a canister in the freezer for four hours until it hit -4* just to see what would happen. As expected, the stove ran like a furnace for about two minutes and then fizzled off and performed just like Hikin' Jims video. No one including Soto claims that the stove would perform down to those temperatures but I figured what the hay. As someone else mentioned, if I would occasionally shake the canister, it would resume full performance for 10 or 20 seconds and then the flame would drop again. I could still boil water but it would take three times as long.

Those would be temperatures for white gas or inverted canister so basically a pointless experiment but I had a few minutes to kill.

Peace out.

"As someone else mentioned, if I would occasionally shake the canister, it would resume full performance for 10 or 20 seconds"

So, what you need is a flame-powered fuel stirrer. That sounds almost like something that would have been found on an early spacecraft.

–B.G.–

The other question I have or might affect things is this on Jim's blog:
"Boiling point of n-butane at 6,000'/1800m: About 19F/-7C"

The boiling point of liquids typically drops with altitude. I don't have any altitude data for butane but 19F at 6000ft seems resonable.

Isn't the above in an open system and it is the internal pressure of the canister that in the key? And, closer to sea level pressures (and could be higher)?

Not sure what you are asking. What is important is the pressure difference between the inside of the canister and the external air pressure. If both are the same than no fuel will flow. If you were at sea level at 32 degrees the stove will only work as long as there is propane or isobutane in the canister. But once that Burns off the pressure difference goes to zero and the stove goes out.

At temperatures below the boiling point of the fuel the only thing you can do to keep the stove working is to heat the canister up.

"The other question I have or might affect things is this on Jim's blog:
"Boiling point of n-butane at 6,000'/1800m: About 19F/-7C"
Isn't the above in an open system and it is the internal pressure of the canister that in the key? And, closer to sea level pressures (and could be higher)?"

"Not sure what you are asking. What is important is the pressure difference between the inside of the canister and the external air pressure. If both are the same than no fuel will flow. If you were at sea level at 32 degrees the stove will only work as long as there is propane or isobutane in the canister. But once that Burns off the pressure difference goes to zero and the stove goes out."

Steven,
What I was pointing out is the effect of pressure on the boiling point of the n-butane.

Open system meaning – not in a canister, an open top container.

My guess is that the the n-butane boiling point in Jim container was closer to the 30-34 degrees then the 19 degrees assumed in the the demonstration. So, the n-butane was mostly in the liquid state.

del

Hi, Ian,

Sorry, not trying to blow you off. I promised my daughter that I would take her hiking, and I needed to get her out the door. Three year olds can be very tempermental; it’s best to go when they are willing rather than to wait and risk them changing their mind.

I think others have actually answered fairly well, but let me talk more about why I chose the test conditions I did (fuel, temperature, elevation, etc.).

First, my objective: Test the Soto OD-1R Microregulator stove in cold induced low canister pressure conditions. I wanted to answer the question, “can a Soto Microregulator compensate for loss of canister pressure due to cold?”

Now, at what point does canister pressure really start to fall off? Well, generally about ten Fahrenheit degrees (about five Celsius degrees) above the boiling point of the fuel. And what are the boiling points of the fuels inside a canister? Well, regular butane boils at 31F/-0.5C, isobutane at 11F/-12C, and propane at -44F/-42C. So, adding about 10 Fahrenheit degrees to the boiling points, we get our critical test temperatures: 41F/5C for butane, 21F/-6C for isopbutane, and -34F/-37C for propane. Note: I could also use a blend of fuels, but the computations necessary for calculating the boiling point are beyond me.

Now, I live in Southern California. Temperatures like those described above are a little hard to come by — but in the mountains such temperatures abound. There’s just one catch: Boiling points fall by about 2 Fahrenheit degrees for every thousand feet of elevation (about 1 Celsius degree for every 300m of elevation). I went to 6000′ of elevation, therefore the boiling point will be 12 degrees lower than at sea level (and the critical temperature, boiling point + 10).

Now, I can use any fuel I want, so long as I am at the critical point (about 10F above the boiling point). The easiest to use is butane for someone in Southern California simply because the temperatures are relatively warm here. It’s hard to find temperatures cold enough to really test isobutane and propane here.

Basically though, it doesn’t matter which fuel one tests with, so long as one tests at a temperature appropriate for that fuel. Again, the point is to test at the point where canister pressure is really going to fall due to cold.

I believe I did just exactly that. Look the flame in the “long” video on my blog. It is robust. That means there was good canister pressure. But at the end of the video, the flame was very small. That means there was poor pressure. What happened in between? The canister got cold. The regulator valve was not able to compensate for the loss of pressure in the canister.

I’m really tired after my hike, so I hope I’m making sense.

HJ
Adventures in Stoving

well said Jim

and what do you mean, going out hiking rather than defending yourself??? : )

and Jim said the Soto was pretty good, but people claim it works better at cold temperatures than a regular upright. I think Jim did pretty good showing that claim is not valid. But, the Soto is still a good upright.

I don't think it makes any difference which upright – Gnat is 1.7 oz, Pocket Rocket and others weigh 3 oz, Soto in between – no significant difference

The only stove that's a little better is the Jetboil Sol Ti, which weighs the same when you include windscreen and pot weight, but Jetboil uses a little less fuel which is where the weight is.

" There's just one catch: Boiling points fall by about 2 Fahrenheit degrees for every thousand feet of elevation (about 1 Celsius degree for every 300m of elevation). I went to 6000' of elevation, therefore the boiling point will be 12 degrees lower than at sea level (and the critical temperature, boiling point + 10)."

Jim,
What about the issue of the n-butane being in a canister? For the inside pressure of the canister to equal the outside pressure; wouldn't the volume/size of the canister have to increase while the amount of the fuel inside remained the same?

If my understanding is correct there is a 23% decrease in air pressure from sea level to 6,000ft.
http://www.endmemo.com/physics/pressurealtitude.php

If, I'm correct that means that the n-butane was below or at the borderline of its boiling temperature during the test.

Also, what was the temperature of the canister at the beginning of the test (not air temp)? Was it possible that they were warmer then the air temps so there was a good amount of n-butane in the gas state?

Did you weight the canisters before and after the test to see which burned more fuel?

And it was interesting that there was a difference in canister temps between the two. Yes, I did watch the long video!

Anyway – thanks for taking the time to stand in the cold to do this.

Jim,

Thanks for your response; that was really informative. I was on the trail yesterday as well with my kids/nephews ages ranging from 7-12. Not necessarily as temperamental as a three year old but my apologies to any fellow hikers on the trail for the chaos I unleashed.

BLUF I don't regret purchasing the Soto but I wouldn't steer anyone towards it vs any other canister stove. I'd probably buy the Sol Ti if I had to do it all over today.

I originally purchased this set up over the Sol Ti with the perceived benefit of having the ability to cook over a fire or Esbit if I encountered a system failure. I've seen people use Esbit with their Sol Ti pot but I have concerns that this may damage the fins in the long run.

It appears from reading reviews that the weight of the Sol Ti can be reduced to ~7.8 ozs if you get rid of all of the unnecessary extras which is close enough weight comparison to my set up. I can only milk out 14 16oz boils from the Soto using a 100g canister when I use the optional wind screen. Reviewers indicate that they are achieving 24 16oz boils from their Sol Ti. I'd gladly trade whatever benefit my system has (real or imagined) for those 10 extra boils.

My absurd test of throwing the canister in the freezer (-4*f) resulting in a 2 minute blast before my stove performance dropped shows why the Sol Ti would excel over the Soto in colder temperatures. It would boil the water or at least have it hot enough to rehydrate food before the performance would likely drop off.

Sousaville on Youtube ran some tests on the Sol Ti vs Reactor in conjunction with frozen canisters which seems to support that general theory.

Paul Mason wrote: > What about the issue of the n-butane being in a canister? For the inside pressure of the canister to equal the outside pressure; wouldn’t the volume/size of the canister have to increase while the amount of the fuel inside remained the same?

If my understanding is correct there is a 23% decrease in air pressure from sea level to 6,000ft.
http://www.endmemo.com/physics/pressurealtitude.php

If, I’m correct that means that the n-butane was below or at the borderline of its boiling temperature during the test.

Paul, the key difference in pressures is the relative difference between the inside (the canister) pressure and the outside. As gas is drawn off, pressure starts to equalize between the inside and the outside. At the point no more gas issues forth, the pressures are equal. Ultimately, it is the ambient air pressure and canister temperature that determines how much flow you’ll get from a canister.

But that aside, consider how large the flame was at the beginning of the test. Clearly, the temperature of the canister was such that there was good pressure. Had the canister temperature been hovering around the boiling point of the fuel, the flame would have been small from the beginning which it was not.

Paul Mason wrote: > Also, what was the temperature of the canister at the beginning of the test (not air temp)? Was it possible that they were warmer then the air temps so there was a good amount of n-butane in the gas state?

I had been out for the day in fairly chilly temperatures (fog, a few flakes of snow falling throughout the day). I took the canisters out of my pack before I started setting up. They were on a snow free metal surface that had been outside all day. Metal is a very effective conductor of heat. At the time of the test, the sun had been behind a high ridge to the west for a couple of hours. No sun had been warming the metal in other words. I’m reasonably sure that the canisters were at ambient temperature.

Paul Mason wrote: > Did you weight the canisters before and after the test to see which burned more fuel?

No. My interest here was not fuel efficiency testing but rather to see if the Microregulator could maintain flame size in cold conditions. It could not.

Paul Mason wrote: > Anyway – thanks for taking the time to stand in the cold to do this.

I just get so darned curious about these things that sometimes I have to see for myself. :)

HJ
Adventures In Stoving

"I just get so darned curious about these things that sometimes I have to see for myself. :)"

Jim,
Thanks again – I learned some more – I didn't know about that pressurization equalization.

Now Ian has got me wondering about this:
"I can only milk out 14 16oz boils from the Soto using a 100g canister when I use the optional wind screen. Reviewers indicate that they are achieving 24 16oz boils from their Sol Ti. I'd gladly trade whatever benefit my system has (real or imagined) for those 10 extra boils."

I read a hiking board where avalanches are a concern. It is amazing all there is to know. Looking back over some hikes in mountainous snow areas I see how stupid I was. Now at least I know that I don't know.

James Klein wrote: > I… think that Jim used butane for his test, to see if the regulator provides any benefit over a normal valve as the fuel approaches its boiling limit.

Yes, exactly. Since butane has the highest boiling point of the three fuels commonly used in gas canisters, I chose butane. Finding weather sufficiently cold is tough in Southern California if one wishes to use isobutane or propane.

Steven Franchuk wrote: > Jim’s test is actually very good… When Jim filled both his canisters with butane he eliminated the biggest variable in most other reviews and test. The only variables in Jim’s test were the stoves.

Exactly. That was exactly what I was after.

Stuart R wrote: > By using n-butane, Jim eliminated one of the major variables in stove testing: the fuel. With a blended fuel, not only are you not certain of the precise percentages when the canster is new, but the percentages change as the canister is used, as the more volatile gas boils off more quickly, so the pressure in the canister is constantly varying.

Spot on (and good explication). And why use a complex test when a simple one will do? With butane, we have fuel whose composition and boiling point are known and do not change as the burn progresses.

Jerry Adams wrote: > Jim said the Soto was pretty good, but people claim it works better at cold temperatures than a regular upright. I think Jim did pretty good showing that claim is not valid. But, the Soto is still a good upright.

Thanks for bringing that up, and, yes. The Soto OD-1R is the nicest lightweight canister stove with auto ignition that I know of. Yeah, the pot supports are a little wonky, but the new version, the OD-1RX should fix that. The pot supports fold up compactly but expand out to provide some real pot support. So, the stove itself is very nice. I just don’t see a practical cold wx advantage. In a way, I think the noise about the Soto Microregulator having a cold wx advantage is a disservice to an otherwise very fine stove.

HJ
Adventures in Stoving

I just wanted to add a few comments.

Nice job with the write-up Hikin' Jim whether Soto intended it or not you are doing a good job dispelling some myths that are obviously floating around (given some peoples unwillingness to accept your results even after you laid out exactly what you did).

I defense of Soto what I think they are trying to do is simply show how their regulator automatically adjusts to changing bottle conditions (which is to get colder over time as the tank blows down). That is why a regulator has advantages over a needle valve. As tank pressure drops the regulator will automatically open up. To get the same performance out of a needle valve you would have to slowly open it up over time. They frame the advantage in terms of as the tank gets colder, which some people have incorrectly assumed means the stove has a cold weather advantage. Soto certainly seems to have caused confusion and it is good that you are clarifying.

Ian, I hope you understand what happened in your experiment as it shows a good reason why someone should not conduct these types of experiments with fuel mixture. When you stuck your tank in the freezer you condensed out most of the butane leaving mostly propane in the vapor volume. That little flash you got when you fired up your stove was the propane burning off. Your experiment drastically changed the mixture ratio of your fuel tank. No such uncontrolled factors occurred in Hikin' Jim's experiment because he used a pure butane tank.

"As tank pressure drops the regulator will automatically open up. To get the same performance out of a needle valve you would have to slowly open it up over time."

That doesn't seem very useful to me.

You have to watch the stove regardless. When it reaches boil you want to turn it off. Any flaming device should be watched carefully to make sure it doesn't spread.

Typically, I'll start the stove, after maybe one minute the canister cools so the flame level reduces, so I'll turn it up. Not a big deal.

On the other hand, not being very smart, sometimes after a while I'll wonder why it's taking so long and it occurs to me that it has to be turned up. It would be a little nice for it to stay at the same level automatically.

So, the regulator does provide a little usefullness.

Thanks and yes I understand. HJ ran his experiment in a way to rule out variances in fuel mixtures which can't be controlled for or measured due to discrepancies in fuel mixtures.

I ran mine in a way to see how the stove would perform in a variety of temperatures using commercially available fuel as that is what I'll personally be using in the field. I try to learn the limitations of my gear in a controlled environment (e.g. home or day hikes.)

I've previously apologized for my snarky and inappropriate post/response and I'll once again say thank you for the useful information.

Ben Hayes wrote: > Nice job with the write-up Hikin’ Jim whether Soto intended it or not you are doing a good job dispelling some myths that are obviously floating around. … Soto certainly seems to have caused confusion and it is good that you are clarifying.

Ultimately, that’s what I hope will come out of this. This is a very nice stove. It’s just not better in cold weather than other stoves.

Ben Hayes wrote: > In defense of Soto what I think they are trying to do is simply show how their regulator automatically adjusts to changing bottle conditions (which is to get colder over time as the tank blows down). That is why a regulator has advantages over a needle valve. As tank pressure drops the regulator will automatically open up. To get the same performance out of a needle valve you would have to slowly open it up over time. They frame the advantage in terms of as the tank gets colder, which some people have incorrectly assumed means the stove has a cold weather advantage.

Some have compared a regulator valve to a cruise control on a car. The regulator valve can keep your flame constant so long as there is more pressure in the canister. The problem of course is that even at temperatures of 18C (64F), per Randulf Valle’s testing, you still reach a point where canister pressure falls to the point where the regulator valve can no longer compensate and the flame begins to decrease in size. This pressure fall off begins after about 10 minutes, and that’s in temperatures that most of us I think would call fairly warm in terms of backpacking.

What I’d like to see here is more testing where the canister temperature is more than 10 Fahrenheit degrees but less than 20 Fahrenheit degrees above the boiling point of the fuel. The Soto OD-1R may have some practical advantage here.

HJ
Adventures In Stoving

"What I'd like to see here is more testing where the canister temperature is more than 10 Fahrenheit degrees but less than 20 Fahrenheit degrees above the boiling point of the fuel. The Soto OD-1R may have some practical advantage here." -HJ

Yeah I agree. I think the "cruise control" feature of a regulator isn't a huge advantage in this situation as you can tell from this testing. It takes quite a bit of burning before a noticeable change in flame size is observed on the gnat.

I've been spending some time thinking about this and what I came up with is that with a regulator valve you *could* have the possibility that the valve would open up much more than would be safe on a needle valve. If you put a huge needle valve on a stove, Murphy says, someone is going to crank it completely open on a hot day with a full tank and that could lead to thermal run-away (big boom!). With a regulator the valve would only open up completely when tank pressure is low. The valve would automatically close down to a safe level on a hot day and be able to open up much more than a needle valve in that 10-20 °F range.

If you open the valve more, then the canister will cool more due to evaporative cooling which will reduce pressure

Just having a bigger orifice is not a total solution for cold weather operation

Jerry Adams wrote: > If you open the valve more, then the canister will cool more

True, but there’s a time lag there. So long as your canister’s temperature stays about 10 Fahrenheit degrees above the boiling point of your fuel, you should be able to adjust your valve to keep a steady flame. The Soto should theoretically make the adjustment for you.

HJ
Adventures in Stoving