Editor’s note: This feature article, by BackpackingLight.com subscriber Roger Caffin, offers one perspective that considers the performance comparison between two liquid fuel stoves: the MSR Simmerlite and the Coleman Xtreme. The conclusions, comments, and opinions derived in this article belong solely to the author, and have not been endorsed or verified by BackpackingLight.com or the BackpackingLight.com Product Review Program or its staff.
Translation key from Australian English to American English:
petrol = white gas
gas = butane/iso-butane/propane mixes, i.e. canisters
The Coleman Xtreme and MSR SimmerLite, packed, with fuel containers.
The Coleman Xtreme and the MSR SimmerLite do look rather similar, especially when packaged up in the bags provided. They weigh almost exactly the same when equipped with ‘full tanks’ of fuel. However, underneath they are quite different.
The MSR SimmerLite is an updated version of the classic WhisperLite. The burner weighs 181 grams (6.4 oz) with all three legs and hose installed. The pump weighs 64 grams (2.3 oz), a slight increase from the old version’s 49 grams (1.7 oz). The smallest MSR fuel tank (11 fluid ounce volume) weighs 69 grams (2.4 oz) without a cap; the cap weighs an additional 10 grams (0.4 oz) but can be left at home so is not counted. With the tank filled to the recommended level, total weight is 290 grams (10.2 oz), or 221 grams (7.8 oz) of petrol. A 12-gram (0.4 oz) tool kit with multi-purpose spanner, mineral oil for lubricating the washer on the pump, and a spare O-ring for the tank-to-hose coupling is included. The total weight of all components and a full fuel bottle is about 547 grams (19.3 oz). Additional items that many users will choose to leave behind are a 21-gram (0.7 oz) stuff sack and a multilingual instruction manual.
MSR claims that this stove’s “shaker jet” technology makes cleaning easy. The shaker jet is a heavy object inside the jet which, when the stove is shaken, pokes a wire through the jet to clean out any muck which lodges there. I think this feature implicitly acknowledges that these stoves do get blocked jets. For more serious troubleshooting, the whole stove disassembles with the spanner for field service. The manual’s instructions on this procedure are good, but I recommend a practice run at home before taking it to the mountains. I would strongly recommend that disassembly be done over a large cloth or hat to catch all the bits and keep them clean.
The stove hose is a little short, but well reinforced. The coupling into the tank is long and well secured with a spring clip. If you use a windscreen around the stove, which is recommended, the hose length will not be a problem.
This is the stove that I use for all my winter ski touring trips. It looks quite similar to the SimmerLite, except for the rather large and heavy gas regulating valve assembly on the end of the hose. The burner weighs 314 grams (11.1 oz). There is no pump. The smallest fuel tank weighs 68 grams (2.4 oz) and holds 170 grams (6.0 oz) of gas, for a total of 238 grams (8.4 oz) for a full fuel bottle. (I consider this amount of gas to be comparable to the 221 grams (7.8 oz) of petrol that the small MSR fuel bottle contains.) The total weight of a full fuel bottle and all components is therefore about 552 grams (19.5 oz), as compared to 547 grams (19.3 oz) for the SimmerLite. It too comes with a little nylon bag (31 grams, 1.1 oz).
No tools or service information were supplied with the stove, although a maintenance kit is available and recommended. The hose is slightly longer than the hose on the SimmerLite.
I must say this stove does have a ‘clean’ appearance, and the burner itself is quite light compared with some of the older models. There is a thin generator tube running around the edge of the burner. From my experience with petrol stoves, I have to say the length of this tube looks like a massive overkill: some petrol stoves have far shorter generator tubes. However, I think the reason for the length is to allow the petrol to be vaporised even when the stove is running at a very low flame. The effectiveness of this is discussed below.
The pump that came with the stove is a newer model than on my other MSR stoves. There have been some small engineering refinements, but the basics are still the same. It should be possible to swap the pumps around between stoves. The manual gives adequate instructions on filling, pumping, and checking for leaks, with an emphasis on safety. The stove includes a flexible windshield, a stove base of the same material, and a nice little kit of spare parts. The windshield is the standard MSR heavy aluminum foil style that is normally wrapped around the fuel tank when traveling. I found its height to be inadequate. The foldable stove base is not durable and is too soft to provide any real additional stability to the stove. Its only useful purposes are to catch spilled fuel or to insulate a surface from the heat of the burner.
My first impression of this stove was that the valve assembly was rather large: but then, you don’t want the gas connection falling off, do you? The first bit of the hose that protrudes from the burner is rigid: use care to avoid damaging the junction between the hose and burner. The hose is thin compared to the SimmerLite hose and the generator tube is smaller. The stove does not include a windscreen or stove base.
The gas tank is similar in size to a small MSR fuel bottle. People sometimes complain about the weight of the empty gas tanks: at 68 grams (2.4 oz) I am not sure what they are moaning about. A small ‘can opener’ is provided with the stove. This is designed to allow you to puncture the tank after you have emptied it, to allow it to dry in the sun. The empty tank can then be recycled with soft drink cans. Finally, every gas cartridge is supplied with a plastic clip-on lid to protect the outlet valve from dirt or debris. Strangely, Coleman does not provide a cover for the open end of the valve assembly.
Assembly of the MSR SimmerLite is easy. Fill the fuel tank, insert the pump, and give it the recommended twenty strokes. Then, lubricate the end of the hose before inserting it into the connector in the pump. The manual recommends using spit or oil, which seemed a little primitive. Instead, I used a very small amount of silicone O-ring grease that I’d gotten from another stove spare parts kit. Finally, extend the stove’s three folded legs.
Assembling the Xtreme is extremely simple. Extend the legs, then push the end of the gas cartridge into the valve unit and give it a small clockwise turn. It clicks into place. It took me a couple of tries to get the feel for it, but after that it was easy.
I fired the stove up for the first time on a slab of rock outdoors. The instructions are fairly clear: you open the valve and let fuel wet the whole burner head – without soaking the surrounds of course. Then you shut the valve and light it up. The burner head is rather cunning, it has a rim around the edge that holds some of the priming fuel. There is also a small cup around the bottom that will collect a small amount of spilt fuel. The flame heats the generator tube quite well. When the priming flame has died down you open the valve on the tank – carefully. You do not need any special priming paste or fuel; the normal fuel does just fine.
The usual priming flare was about 30 centimeters (12 in) high: not the sort of thing you want in a tent, of course. The manual recommends that you preheat the stove with fuel in the generator tube: this ensures you start with hot fuel rather than chilling the generator tube with cold fuel when you open the valve. This is an important point for all liquid fuel stoves, both petrol and kerosene.
Assuming I start with a tank of fuel which is still under pressure from the last time I used the stove, that I have a stable base to put the stove on, that the stove is plugged in to the tank, that everything is to hand and I have had some practice, I find that it takes me about 1 minute 45 seconds to get this stove going. That’s not too bad – kerosene takes much longer. How long does it take you to get all the bits and pieces together before this stage? Well, that’s up to you and your degree of organisation.
The first time I lit the Xtreme up I simply turned the control valve on gently while holding a lighter next to the burner. It worked just fine. There was no flare up at all, and I routinely light this stove inside my tent. There is a small generator tube at the burner, but it did not seem to need any preheating. Of course, as soon as the flame is alight, the tube gets hot. So if I start from the same state as above, with everything together, it takes me about 2 seconds to get this stove running. It feels much faster, but in the overall scheme of things there is not much to the difference.
Operation: full bore and simmering
Stove setup for the simmer and boil (less the pot lid) tests
I ran two sorts of tests here. The first was at full power to assess the minimum time to boil 1 litre of water; the second was to see how slowly I could heat water to test simmering capability. The first test is all about the big macho advertising claim: “Our stove boils faster than yours.” Frankly, so what? I never run a stove flat out like this, but you can’t have a stove review without this sort of data. As shown in the picture, I set up the stove with a 180-millimeter (7.1 in) diameter stainless steel pot containing 1 litre of water, put my folding windshield around the stove and pot, and put a digital thermometer in the middle of the pot. The top of the pot was covered for some tests; for others I did not bother, as I wanted worst-case results. The temperature of the water was logged every 5 seconds. Once the water was really boiling I turned the stove off and let the water start to cool.
The results for heating 1 litre of water are shown with the SimmerLite in red and the Xtreme in blue. Note that both graphs are nearly linear in the heating stage; both stoves heated water at a constant rate. The slight change in rate near the top is due to evaporation of steam, since this test was done without a lid. The SimmerLite reached a rolling boil from 21 °C in about 4 minutes 45 seconds, while the Xtreme took slightly longer at 5 minutes 15 seconds. These times are longer than the typical manufacturer claims. I had the SimmerLite going as fast as it could, but I did have the Xtreme turned down a fraction from the maximum. This was due to my reluctance to have flames roaring up the sides of the pot. The Xtreme may have had a slightly faster boil time if I had allowed this.
Time to boil 1 litre of water
The SimmerLite and the Xtreme boiled 1 litre of water in about the same amount of time.
In my opinion, the second test is more important: can I simmer a stew? For this, I need the stove turned down as low as possible. I tested for this by turning each stove down as far as I dared. The Xtreme stove turned down to a very low level and remained stable. The SimmerLite was a different matter. According to reports from other users of the SimmerLite, MSR has said you have to get the stove hot and then turn it down slowly. I interpreted this to mean that it was important to make sure the whole generator tube was hot and remained hot. Even so, I found the flame height on the SimmerLite rather unstable: I could hear the burn rate going up and down without intervention from me. I considered trying to adjust it continuously, but decided this was not acceptable. In the field I am usually busy with other things while dinner is cooking. The test arrangement was the same as before except that in this case I put a lid on the pot to limit evaporation.
Again, the SimmerLite is in red while the Xtreme is in blue. The SimmerLite graph starts at a higher temperature. This is because I had to spend some time fiddling with the valve to get as low a burn rate as possible. In the end, however, the flame on the SimmerLite just went out. That’s why the red graph stops where it does: I quickly turned the valve off when I heard the flame go out. For reasons of both safety and cleanliness, you do not want fuel leaking everywhere! I found it very difficult to control the rate of heating with the MSR stove on its lower settings.
Slowest rate of heating 1 litre of water
The Xtreme is far better at simmering than the SimmerLite.
The SimmerLite heated at a rate of 39 degrees Celsius in 8 minutes, or 4.9 degrees per minute. The Xtreme heated at a rate of 39 degrees Celsius in 20 minutes or 2.0 degrees per minute. This means the Xtreme could be turned down to less than half the heating rate of the SimmerLite – plus it was very stable in that mode. In summary, the Xtreme is far better at simmering than the SimmerLite.
The Xtreme turns down so well that extrapolating the above graph suggests that in a bit over 30 minutes the temperature would reach about 70 °C and not go any higher! That is, the heat loss from the pot at high temperature would match the input from the stove – this is simmering! The data from the SimmerLite suggest that equilibrium could have been reached around boiling point if the valve had not crept shut and turned the stove off. It will simmer, sort of, but not very easily or reliably.
I discussed the three-leg design of both stoves above. In addition to stability on the ground, however, it’s also important that the pot be stable on the stove. You wouldn’t want your dinner to go sliding off onto the ground!
There are two standard techniques manufacturers use for preventing a pot from sliding off the stove. To contain pots, the inner ends of the pot supports can be tilted upwards to make a cradle. This does not work if the pot is larger than the pot supports, as mine is. The second technique is to roughen the top surface of the supports. Not so much that they chew into the base of a pot and wreck it: just enough to stop any sliding.
The SimmerLite has both the tilted arms and little bumps on the arms. They are smoothed off without any sharp edges. The Xtreme also has tilted arms and notches along the top, but the notches do not reach to the highest points. You can run your hand over the arms of both stoves without getting any scratches. My stainless steel pot seemed to be stable on both stoves, so there appears to be just enough roughness on each one.
I mentioned in my general review of stoves, Got Gas? Stove Theory and How They Work, that you should expect to use a little more weight of petrol than of gas, and that I normally use about 30 grams (1.1 oz) of gas per day to cook for two people. The fuel consumption data during this trial matched those figures, but are of limited value for any other user. The reason is that everyone uses their stove differently, and cooks different amounts. So all I can say is that both stoves are efficient examples of their class.
While fuel consumption was as expected, it may be worth noting that the cartridges for the Xtreme are rather specialised and may be hard to come by in a small country town. It is a specialised winter stove. But then, while spending six weeks walking in the French Pyrenees in 2002 I was able to find standard screw-thread (EN417) gas cartridges more often than I could find Coleman fuel or white gas. In Nepal you might be hard pressed to find anything other than kerosene. You will need to research resources where you are going before deciding what sort of stove is appropriate.
During the course of this field test I did not have to do any maintenance on either stove. MSR provides tools, and these tools were sufficient to field strip the stove. Coleman did not provide tools, but I have never needed to field strip a gas stove anyway.
By now you may have got the impression that I have a slight bias towards the gas stove – towards any gas stove! This is true, and this test has not altered my opinions. Both stoves are good stoves and will give good service. It’s just that I find gas (canister) stoves much easier to use than petrol (white gas) stoves.
Figures in graphs are quoted courtesy of www.bushwalking.org.au/FAQ/.
Roger Caffin is a consultant research scientist. He maintains the aus.bushwalking FAQ and Confederation of Bushwalking Clubs NSW web sites. He is the Editor of the Confederation’s quarterly magazine and a tester at BackpackGearTest.org. Roger started bushwalking at 14 with ex-Army gear. He took up rock climbing and remote exploration walking at University with the girl who later became his wife. Over the last four to five years he and his wife have converted to ultralightweight gear. They prefer long, hard walking and ski-touring trips, from Tasmania to north of Sydney and in Europe. They spend at least two days per week walking or ski touring.