Soto OD-1R Canister Stove Product Review

This Japanese stove is small, light, and well-made, with a unique miniature pressure regulator instead of a needle valve.

Overall Rating: Average

It's small, light, well-made, and works reasonably well, but its CO emissions are definitely too high for comfort. The marketing claims for the merits of the pressure regulator valve are misleading or worse.

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by Roger Caffin |

Soto OD-1R Canister Stove Product Review

Overview

There are many small upright canister stoves on the market with Western brands on them, and after a while one gets to recognise not just the basic designs used but also, in many cases, the Chinese or Korean factory the stove probably came out of. This stove is not one of those. It is made in Japan and the quality of the stove is uniformly high. The weight is at the lower end of the spectrum, the power output is good, and it has an integrated piezo-igniter system. Its chief claim to fame however is the unique 'valve' system used. It does not have the conventional needle valve: it has a miniature pressure regulator instead. We will review the various features in turn, with the pressure regulator given extensive coverage at the end.

The piezo-igniter seems well made. The interesting bit is that the insulated high voltage wire goes up the inside of the burner column to emerge at the top of the burner. You can see a small, bright, pointy bit right at the top of the burner head: that's the spark gap. This means that the wire and spark gap are well protected from damage. The metal housing around the piezo mechanism itself seems tight and compact. How long the spring mechanism inside the housing and behind the button will last - that I do not know.

It has been claimed that a piezo-igniter (any brand) will only work up to 2,000 - 2,500 meters (6,000 - 8,000 feet). Part of the reason for this is that there is only so much energy in the spark, and if the air and the gas is very cold, the spark may not be able to ionise the gas and break the molecules down. Whether or not this is strictly correct, there is no denying that it might be a smart move to always have a spare lighter (or two) at any altitude.

In use the stove has to be operated slightly differently from other stoves. With a conventional needle valve, you turn the valve off by screwing it in until it comes to a firm stop. With the pressure regulator, there is no firm stop. Instead, you screw the valve in until the flame goes out, then just a little bit further. To start a needle-valve stove, you open the valve from its easily-sensed closed position by a fraction of a turn. With this pressure regulator valve, you have to start winding the valve open and use the piezo many times as you go. Since you can overshoot on the shutting off (no hard stop, remember), it may take a turn or two before gas comes out. This can be rather alarming the first time you experience it (help, it isn't working!), but it's something you get used to after a few starts. For the rest of the control range, there is no real difference in behaviour.

SOTO OD-1R Canister Stove Product Review - 2
Morning tea on the banks of the Colo River, Wollemi NP, Australia.

The power output is claimed to be up to 3,260 W. I think that may be possible with a new canister on a warm day (when the canister pressure is high). Many other canister stoves claim similar power output - but need the same caveat. The claim by Soto that the stove will continue to perform just fine at -5 C (23 F) is seriously misleading however. The claim only works if the canister has an iso-butane/propane mix. If your canister does, then most any upright stove will perform just the same.

Not all brands of canister contain iso-butane: many contain n-butane instead. If your canister has n-butane then, just like any other upright stove on a new canister, it may work at -5 C (23 F) for a while - until the propane in the canister has been almost all used up. Then this stove will die, just like any other upright stove, leaving a canister two-thirds full of n-butane. The claim that owing to the regulator the Soto stove will boil water faster than any other upright stove at -5 C (23 F) flies in the face of basic physics and can be dismissed as marketing spin.

The pot supports are rather cute. You have to slide them up and down to open them out and lock them in position. There is even the word 'SLIDE' with a bidirectional arrow stamped on each arm to remind you. The sliding mechanism seems to work just fine. However, I do wish they held the pot a bit further from the burner, because of the CO emission.

SOTO OD-1R Canister Stove Product Review - 3
CO emission behaviour for the OD-1R stove

The CO emission spikes very high at start-up: almost 300 ppm when measured in the test system we have used for the CO series. It decays steadily, but even after a long time, it is still sitting over 100 ppm. The problem is the usual one of inadequate clearance between the burner and the base of the pot. Vendors often minimise this clearance in order to get slightly higher power output: marketing drive versus customer safety. The graph here shows that CO emission can be reduced by increasing this clearance.

It is worth looking at this problem in slightly more depth. A high level of CO means not enough oxygen (or air) is getting to the flame. Normally most of this air is sucked in through the air holes in the burner column by the high-speed jet of fuel coming out of the jet. The more powerful the jet, the more air gets sucked in. In most stoves the jet is quite small, allowing a high inner pressure P (see next section) to get the right amount of gas coming out - at high speed. But in this case it seems the range for the inner pressure P is lower, owing to design requirement of having the regulator work down to a low canister pressure. The lower pressure drop across the jet requires a large jet hole to get the needed gas flow, which means the jet speed is lower, which means that less air is dragged in through the air holes. To cut a long story short, the design decision to use a fixed regulator with a low output pressure range seems to have resulted in a slightly inadequate amount of air being sucked in, and a higher CO emission.

The instructions do mention The stove can produce carbon monoxide which has no odor and may cause death. The instructions do warn against using the stove in an enclosed space: a warning which should be heeded I think.

The instructions also say NEVER cover the stove with rocks and a windscreen while in use and NEVER surround the unit with wind shields. There is a diagram of the stove with a windshield half way around it and a big cross. I am not sure what 'cover' means, but any stove which cannot be used with a windscreen is pretty much useless in the field. I smell lawyers...

The Pressure Regulator - Reviewed

The novel pressure regulator used as the control valve is interesting. This regulator works well as a control valve, but there has been a lot of misleading marketing spin put about by various distributors selling this stove. The claims seem to be based on the marketing claims made by the Soto company - claims which, while not false, do tend to confuse reality. A lack of knowledge at the distributor end has compounded the problem. We will examine what is really going on here.

SOTO OD-1R Canister Stove Product Review - 4
The control system.

Inside the canister, there is gas pressure, which is a function of the composition of the fuel and the temperature of the canister. This pressure is far too high to go direct into any stove jet: it has to be reduced. This is normally done by the (needle) valve which presents a huge restriction on the gas flow, creating a pressure drop (down to 'P'). The greater the restriction or pressure drop at the valve, the less pressure there is left to push the gas through the jet, and so the less power comes out of the stove.

In other words, there are two places where the pressure is dropped between the canister and the outer face of the jet (which is at atmospheric pressure): across the control valve and across the jet. If there is a lot of pressure drop across the valve there is little pressure drop across the jet. If there is little pressure across the fixed-size jet there is little flow through it. It is identical to having two resistors in series or two taps on a hose.

It is crucial to understand here that the details of how the pressure is reduced (to P) by the control valve simply do not matter. All that matters is how much pressure is across the jet. A conventional needle valve varies the restriction or pressure drop across itself by varying the area of the hole around the needle in the valve, but this is not the only way this can be done. A more sophisticated diaphragm arrangement can be used for this: one which actually is designed to control the output pressure P per se. This latter is what is done in the Soto stove.

The marketing claim made by Soto is that the stove can maintain a constant power output as the canister pressure varies, and this is technically correct up to a point. The pressure P is regulated, and the flow through the jet depends directly on P. The claims made by some retailers and reviewers imply that the regulator will maintain a constant power output no matter what the pressure in the canister falls to, and this is seriously misleading (or false). The pressure regulator will only work while the canister pressure is high enough: it has to be a fair bit above P to be able to regulate. At this higher canister pressure, it does not matter whether a needle valve or a pressure regulator is used to get P. Below that, canister pressure the power output WILL fall.

The big difference is that using a pressure regulator rather than a needle valve means that P, and hence the flow of gas through the jet, and hence the power output, will be fairly constant despite a falling canister pressure. When using a needle valve, the intermediate P and hence the power output will vary. What the marketing claims do not examine is whether this constant power output matters in practice. I don't think it matters at all.

If I want high power (to bring water to the boil for instance) I open the valve so the stove is roaring away. If the power output varies a bit - who cares? If I am simmering, I turn the stove right down, but any small variations don't worry me either because I am usually monitoring dinner fairly closely and may be varying the power output as I go. To be sure, if I was running the stove for half an hour straight there might be some significant changes in the power output which might need correcting - but I never run the stove for that length of time.

Summary

The bottom line then is that the stove is nicely built, the piezo igniter works well, and the pressure regulator valve works very smoothly, but the CO emission is a bit higher than I am really comfortable with. The performance in the field does not show any special advantage to the unique pressure regulator valve.

Specifications and Features

Brand Soto
Country of origin Japan
Model OD - 1R
Power output (claimed) 3,260 W
Material Brass, aluminium, stainless steel, plastics
Size, packed 78 H x ~55 D mm (3.2 x 2 in)
Pot support diameter 110 mm (4.3 in)
Weight (claimed) 73 g (2.6 oz)
Weight (measured) 72 g (2.6 oz)
MSRP n/a, but retail US$65 has been seen

What’s Good

  • Well made
  • Light
  • Compact

What's Not So Good

  • High CO emission
  • Excessive and misleading marketing spin
Disclosure: The vendor provided this product to the author and/or Backpacking Light at no charge, and it is owned by the author/BPL. The author/Backpacking Light has no obligation to review this product to the vendor under the terms of this agreement.
 


Citation

"Soto OD-1R Canister Stove Product Review," by Roger Caffin. BackpackingLight.com (ISSN 1537-0364).
http://backpackinglight.com/cgi-bin/backpackinglight/soto_od-1r_canister_stove_product_review.html, 2010-03-23 00:00:00-06.

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Forum Index » Editor's Roundtable » Soto OD-1R Canister Stove Product Review


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Addie Bedford
(addiebedford) - MLife

Locale: Montana
Soto OD-1R Canister Stove Product Review on 03/23/2010 12:49:56 MDT Print View

Companion forum thread to:

Soto OD-1R Canister Stove Product Review

jeff arnfield
(Windward) - F

Locale: NE Tennessee
CO is the primary negative? on 03/23/2010 14:21:30 MDT Print View

Another fine review, Roger, as always.

I have been looking at the stove and was concerned that the pot supports flip down rather readily when pans are moved. I did like the size, weight and igniter.

Apart from CO levels, nothing to recommend against it except for the hoopla and expense? I do not now cook in my tent, but all things being equal I'd like the option without the asphyxiation hazard.

Boiling times, which you don't list, are interesting, but much like sleeping bag temperature ratings in that there are enough variables to render them almost meaningless.

Did you happen to measure fuel consumption per 500 ml boiled under some standard conditions? Swine of a Jetboiler that I am, I can count on using about .2 oz / pt under a broad range of field conditions.

Addie Bedford
(addiebedford) - MLife

Locale: Montana
Roger on 03/23/2010 19:09:29 MDT Print View

Jeff, Roger's out walking. I expect you'll be hearing from him when he's back in range!

jeff arnfield
(Windward) - F

Locale: NE Tennessee
Best excuse there is! on 03/23/2010 19:40:03 MDT Print View

How dare he go do what we all spend lots of time just discussing! Sigh. I suppose we'll just get on until he returns. ;^)

Stuart R
(Scunnered) - F

Locale: Scotland
Re: fuel consumption on 03/24/2010 04:33:12 MDT Print View

> Did you happen to measure fuel consumption per 500 ml boiled under some standard conditions? Swine of a Jetboiler that I am, I can count on using about .2 oz / pt under a broad range of field conditions

Fuel consumption has more to do with the pot than the stove
What matters is the thermal coupling between the combustion gasses and the pot.

The main factors are the size of the flame, the diameter of the pot, whether it has heat exchanger fins and external factors such as wind.
Your figures for the jetboil indicate a thermal efficiency of 68%
The jetboil pot on another stove will yield a similar value, change the pot or the flame size and you will get a different value.

I get 50-60% efficiency in the field on several gas stoves (not Soto) with a non-heat exchanger pot, 5" dia but it can drop below 50% with the flame at max or windy conditions.
As a guide, 50% efficiency is 8g gas per 500ml water with 90C temperature increase

Mike Nielsen
(mikenielsen) - F
pizo igniter at altitude on 03/24/2010 05:59:20 MDT Print View

Regarding the comment about a canister stove with a pizo igniter maybe not working above 8K feet. I've used two different titanium stoves with pizo igniter with various brands of gas canisters on both the Pacific Crest Trail and Colorado Trail at altitudes well above 11K feet on numerous occasions and have had no difficulty igniting the gas. Still carry waterproof matches and small butane lighter just in case, however. Thanks for great articles.

Timothy Cristy
(tcristy) - F

Locale: Ohio
pizo igniter at altitude on 03/24/2010 12:11:51 MDT Print View

I used the Soto for a 5-day trip in the Beartooths last year with no problems at over 10k.

Several others in my group have other cannister stoves and I have seen less apparent problems with temperature and cannister issues with the Soto. On my last trip, someone with a Snow Peak Lite Max had to borrow my Soto because their stove wasnt staying lit with their mostly empty cannister. The Soto worked just fine with that cannister.

Tim

Rick Dreher
(halfturbo) - MLife

Locale: Northernish California
Re: pizo igniter at altitude on 03/24/2010 12:37:17 MDT Print View

Some will and others will not. The variables seem to be the spark's strength and location, and the stove's ability to throttle the air:fuel ratio precisely to the point where it will ignite. To work, the piezo spark has to occur within an air:fuel zone between the lower and upper explosive limits and some stoves simply don't make this possible. An external flame or sparking device has a much easier task in accessing the ignition zone.

I've used canister stoves that refuse to self-light at altitude, due to bad design. Others work reliably, even over 10k. FWIW I've never owned a piezo lighter that works much above 6k or 7k feet, and have given up on them completely.

Cheers,

Rick

Tom Kirchner
(ouzel) - MLife

Locale: Pacific Northwest/Sierra
Re: Re: pizo igniter at altitude on 03/24/2010 17:40:48 MDT Print View

"FWIW I've never owned a piezo lighter that works much above 6k or 7k feet, and have given up on them completely."

+1

Ken Thompson
(kthompson) - MLife
piezo on 03/24/2010 17:52:23 MDT Print View

Dead weight if you carry other firestarting equipment. Marketing at work.

James Lantz
(jameslantz) - F

Locale: North Georgia
Soto OD-1R Performance on 03/24/2010 19:52:33 MDT Print View

It seems to me that the Soto stove should be tested against its competitors in cold conditions at altitude or in a controlled environment to simulate these conditions to see if the manufacturers claims are true or false. Only with controlled testing could the piezo function & heat output be tested with canisters in various states of full vs. empty. Anecdotally, the Soto stove seems to work much better in cold than a Primus Technotrail or MSR Pocketrocket even with a near empty fuel canister but what "seems to be" & "what is" can be different.

Jason Brinkman
(jbrinkmanboi) - MLife

Locale: Idaho
We need to get a hypobaric freezer for Roger! on 03/24/2010 23:59:20 MDT Print View

The claims regarding the low temperature performance of this stove have perplexed me since it came out. But I would like to see the definitive control test to put the issue to rest. So how about one of you MYOG specialists draw up some plans for a hypobaric freezer for Roger to test in? This should also solve the spark ignition question. And if possible it should be big enough to be cross utilized for garment and sleeping bag/quilt reviews, allowing for control of temperature AND air pressure (simulated altitude)!

Just kidding of course - I am very satisfied with the answer given in the article a previous posters messages! Thanks for another great review!!

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Roger on 03/25/2010 01:57:04 MDT Print View

First, we should test Roger inside the hypobaric freezer!

--B.G.--

M W
(rcmike) - MLife

Locale: California
Product review or marketing review? on 03/25/2010 14:13:19 MDT Print View

I like the review but would have wanted to see comparison data on performance against other stoves in its category as was done here: http://www.backpackinglight.com/cgi-bin/backpackinglight/lightweight_canister_stoves_test_report.html

Arapiles .
(Arapiles) - M

Locale: Melbourne
Re: Soto OD-1R Canister Stove Product Review on 03/29/2010 06:50:08 MDT Print View

I'd never heard of, or seen, either this stove or this brand and as you may know I've lived in and been in and out of Japan for the last 19 years (including this January when I spent several days wandering around Tokyo's gear stores) so I was a bit curious about it.

I searched on Yahoo Japan and found their website:

http://www.shinfuji.co.jp/index.html

If you click on the "Close up" tab on the top you get some nice photos of the stove in question.

And this is an expensive gas lamp that they have

http://store.sakaiya.com/product_info.php?products_id=41722&DS-STYLE=396ab89f2812f726baafc2d4d837b662

It's interesting that they are now being stocked by stores in Tokyo - either these guys are a re-brand of an older company or someone has invested a lot of money in expanding a brand. Their website says that the Soto brand has been around since March 1992, but as I say, I've never seen them. That may simply be because they're based in Aichi prefecture which is several hundred k's to the south of Tokyo. It just goes to show that Japan is a big place and is very regionalised. And I'm willing to bet that the reason they're now available in Tokyo is as a result of them cracking the US market through REI - odd and circular as that may seem.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: CO is the primary negative? on 03/30/2010 01:41:07 MDT Print View

Hi Jeff

Yes, I would say that the CO emission is the primary negative - apart from the somewhat ridiculous marketing spin :-)

Sorry, I didn't measure the fuel consumption for this stove. As others have said, there is no reason to believe it will be any different from any other small upright canister stove of similar dimensions. It will of course depend hugely on the pot diameter, the effectiveness of the windshield, the power setting used - excatly the same as for any other similar stove.

Don't get me wrong: it IS a well-made stove. But it should be judged just the same as any other upright stove. The use of a pressure regulator does not change anything - awards from other magazines (of lesser technical knowledge) not-withstanding.

Cheers

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Roger on 03/30/2010 02:52:39 MDT Print View

> First, we should test Roger inside the hypobaric freezer!

It's called ski-touring...

Cheers

James Eagleton
(toc) - F
This review doesn't blow on 03/30/2010 22:16:32 MDT Print View

Roger, nice experimental science, I look forward to more quality research.

Your theory is extremely biased. You prove your point by essentially saying "all else being equal, all is equal" Then you imply a couple times that the jet diameter of the Soto is larger. (So you can bash Soto for high CO) Do you know how much bigger diameter the Soto jet is compared to other stoves? Obviously, for a given jet pressure P, the jet with a larger diameter hole will at least partially live up to the marketing hype (of being hotter).

You also say: "The pressure regulator will only work while the canister pressure is high enough: it has to be a fair bit above P to be able to regulate."

How much is "fair" in your opinion. Does a needle valve need more than "fair" or less than "fair" to deliver the same flow with and outlet of P?

Did you "basically" blow into the Soto stove fitting and a needle valve stove fitting with both set for max flow? Maybe, I'm not the experimentalist you are, but I have more respect for the "face of basic physics".

btw, I would not be surprised if the Soto has a slightly less than a 2x advantage at cold temperatures, but slandering new people, Backpacker Magazine?, is not additional data. Also, Soto only claims a specific advantage between 0 C and -5C, so the advantage probably drops off rapidly outside this range. Although the range is small, many of us would like a prompt warm dinner in these conditions.

Cheers

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: This review doesn't blow on 03/31/2010 00:33:30 MDT Print View

Hi James

Perhaps I should start by explaining I have been testing canister stoves for many years, and in addition I have been designing and building canister stoves from scratch for a couple of years. By 'from scratch' I mean starting with sheet titanium, aluminium rod and brass rod; not by converting parts from other bought stoves.

So it may be that sometimes I will make a statement which is perfectly obvious to me but which is presented without full explanation or justification. Sorry about that, but it does make the articles shorter!

"The pressure regulator will only work while the canister pressure is high enough: it has to be a fair bit above P to be able to regulate."
Yes, this is correct. The extra pressure is what gives enough energy to the regulator for it to be able to work, or provide regulation. You can't get something for nothing here. A needle valve does not need this extra pressure drop as it does not 'regulate'. How much extra pressure drop? I have not measured that.

> you imply a couple times that the jet diameter of the Soto is larger
This follows from the basic physics of wanting the regulator to work down to quite low pressures. The intermediate pressure between the regulator and the jet will normally be lower than is found in a needle-valve stove. The higher CO emission follows from the lower-speed jet having more trouble sucking in enough air. I have spent a lot of time working on that aspect of stove design. Please remember that the higher CO levels are measured facts: real basic physics.

> Soto only claims a specific advantage between 0 C and -5C,
Actually, you can get exactly the same performance from an ordinary upright stove if you use the same canister. It's the gas in the canister which determines how well it performs at sub-zero temperatures, not the stove. The SOTO stove might have better 'regulation', but who needs precise regulation?

I will repeat two things here: the stove is well-made, and the marketing spin which I attacked comes almost entirely from the distributors, not from SOTO. SOTO themselves are quite careful in their claims. As far as I can see, the distributor marketing departments are the ones who have twisted the SOTO message into something they want to hype.

> many of us would like a prompt warm dinner in these conditions.
An ordinary upright stove will give you this at exactly the same speed as the SOTO OD-1R. Note however: there will be cases where neither will succeed!

Cheers

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
operation in cold on 03/31/2010 08:30:18 MDT Print View

Nice review as always, Roger.

On the Soto website they have a video showing how the stove maintains flow when you put the canister into ice water.

This seems like marketing hype to me.

You would never encounter this in real life.

It might get colder, slowly, but you should be watching the stove and if it gets too slow, just open up the needle valve.

I worry about the long term reliability of the regulator. It might get clogged or something. This is new technology (?)

On the other hand, it's nice that it's well built.

And the Piezo lighter is nice.

It costs a little bit more than conventional stoves.

I think a MSR Pocket Rocket would be a better buy - more available, cheaper, and long history of people using it.