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MSR Reactor Review

Backpacking Stove

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Price:   Varies from $150 - $200 online  —  Compare at 4 sellers
Pros:  Highly efficient, storm-proof, very fast, easy to use
Cons:  Heavy, pot does not attach to stove, does not simmer, expensive
Editors' Rating:     
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Manufacturer:   MSR


The MSR Reactor was once the king of the hill when it comes to boiling water fast in the harshest climates. It is designed to provide all-conditions performance for one to three people, but lacks the ability to simmer and it functions poorly on low. Now the MSR Windburner may be rendering the Reactor obsolete as it has taken the best features of the Reactor and the Jetboil and rolled them up into one. The Reactor is a great tool for boiling water very fast and will stand up to all kinds of weather.

Get the Reactor with a 1.7L pot if you voyage to cold climates with two to four people. Otherwise, the Windburner is smaller and less expensive, and just as storm-proof. For the best in value, versatility, and durability, get the time-tested MSR WhisperLite for $89.95.

To see how the Reactor stands up to the rest of the stoves we tested check out our full Backpacking Stove Review.

RELATED: Our complete review of backpacking stoves

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Analysis and Hands-on Test Findings

Review by:
Jessica Haist
Review Editor

Last Updated:
February 10, 2015
The Reactor is a leader in its class for fuel efficiency and boil time. We had some concerns with a malfunction while testing this stove, and believe its brother the Windburner provides more bang for the buck.

Performance Comparison

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Glen in an open bivy in the High Sierra, getting his morning brew ready on the MSR Reactor.


As with all the integrated canister stoves we tested, the Reactor is not as versatile as we would like. While it may be a champion at boiling water, the Reactor will not slowly reduce your pasta sauce, fry up an omelet, or cook rice. In fact, this stove simply does not simmer and it is relatively poor at running on low. During our attempts to simmer delicate cuisine, we extinguished the burner dozens of times. Heating less sensitive canned food such as baked beans or chunky chicken vegetable soup still requires a delicate touch and nearly constant stirring.

In contrast to the Jetboil Flash, the Reactor comes sans auto ignitor and lacks the ability to clamp to the pot. This stove's other sore thumb is an awkward single-purpose lid. We would prefer to see a more versatile cover that could also be used as a plate or bowl. We also scored the Reactor low in versatility because of its inability to be repaired in the field, as we discuss below.

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Ian McEleney eats his hard earned Ramen noodles from the MSR Reactor's pot. We like the sturdy handle, but think the lid could use some improvement.

Issues with the Reactor

We experienced a malfunction while testing the Reactor. Thankfully it was in the front-country and not when we were depending on it to cook our meals in the field. While we were doing our boil tests, the Reactor would not light properly and the flame seemed to sit on top of the metal grate and remain a blue wispy flame, not the red hot one we are used to. It took us almost 4 minutes to boil half a liter of water. After contacting customer service at MSR, it was determined that this was indeed a malfunction, and the flame was not behaving as it should. It should have been jumping down to the metallic foam burner itself instead of sitting on top. One potential issue is that we were testing in a garage with very little air movement. MSR told us they have experienced this problem while doing lab tests indoors with no air movement, so they advised us to cook outdoors. They also told us it is preferable to light the Reactor with a Strike Ignitor type lighter so that the sparks land directly on the metallic foam burner. If you use a lighter (or a match) make sure to light the stove at the edge above the MSR logo on either side of the burner. There is a small opening in the top dome where the screen has been stretched to help the flame reach the burner surface. All this taken into consideration, our Reactor still was not working properly and we have sent it back to MSR to find out what went wrong with our model. We don't seem to be the only people who have experienced this problem and have read other reviews online of those who have. That being said, our testers have used other Reactors and have never had problems before.

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Our MSR Reactor malfunctioned, and the wispy blue flame shown here would not "jump down" to the metallic foam burner below. We contacted MSR's customer service to troubleshoot this problem.

With integrated canister stoves, the unfortunate reality is that there is very little you can do to repair or troubleshoot these in the field, so if you are way out there and this malfunction happens, you may be eating cold Ramen for dinner. MSR did give us a quick fix to this particular problem that you can use if this happens to you while you're in the backcountry: If you see a blue flame after lighting the stove, you can briefly place a finger or thumb just in front of the air intakes on either side of the control valve. This essentially acts as a choke (like on a carburetor) to reduce the air intake and richen the fuel mixture. It will make the flame jump down to the metal foam and turn red very quickly. Be careful doing this if the stove is warm as the solid ring around the top of the stove could be very hot. We tried this on our malfunctioning burner and it worked!

Fuel Efficiency

The Reactor is the most fuel-efficient stove we tested when it is working properly. The Reactor's burner has several unique features that make it better than all the rest: (1) It is the widest of all stoves tested (roughly 3.5 inches in diameter). (2) It's surrounded by perforated metal which acts as a windscreen and captures air for the burner. (3) Unlike most stoves which only use convective heat, the Reactor's burner incorporates metallic foam that also dispatches radiant heat. (4) The Reactor includes a pressure regulator that maintains a consistently low pressure throughout the life of the canister. This enables the stove to perform better when canister pressure nears zero and in low temperature, high altitude conditions.

All versions of the Reactor's pots include a built-in heat exchanger that occupies the bottom inch of the pot. This sits on top of a convex burner, blocking wind, trapping heat, minimizing the distance between the pot and stove, and increasing the burner's surface area to roughly twice that of a traditional flat-bottomed pot. Unlike the Jetboil Flux Ring, the Reactor's heat exchanger is constructed to withstand expedition style abuse. The heat exchanger's strong fins are welded to the bottom of the pot, but above it is lower profile.

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THE MSR Reactor heat exchanger. This is a more durable design than the Jetboil Flux Ring heat exchanger.

Unlike many liquid fuel stoves, which roar like jet engines and turn dinner into a shouting match, the Reactor is wholly tranquil. Based on our observations, it is the quietest stove on the market today. The only problem with this is that the Reactor is so quiet, we have to lift the pot up or take off our gloves and put our hands by the vents to make sure it is on occasionally and not just wasting gas.

Boil Time

The Reactor's red hot burner boils water fast. In our tests at 8000 feet, the reactor boiled half a liter of water in 2 minutes and 25 seconds. While it was malfunctioning and we only managed to get a blue flame out of it, it still worked eventually, boiling that half liter in 3 minutes and 54 seconds.

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Head to head testing in windy conditions. The MSR Windburner and Reactor (left) stood up to the test, while the Jetboil Sol barely made it and the Jetboil Flash (right) blew out.

In an 8 mph wind this system boiled a liter of water in 3:16, embarrassing the hugely popular Jetboil Flash, which limped in at 8:44. As conditions worsen (increased elevation, increased wind speed, decreased temperature), the Reactor's performance significantly improves relative to competing stoves. Thus, if you venture high into the mountains and the storm gods deliver as promised, the Reactor will be a trustworthy companion.


For a stove that we like to bring on fast and light alpine missions, the Reactor is not as lightweight as we would like. With a 1L pot the Reactor weighs in at a hefty 14.5 oz, 4.4oz heavier than the Jetboil Sol Ti.The 1.7L version weights 19 oz. That being said, if you consider the Reactor a pot, stove, and bowl all in one, it may save some weight compared to a gas stove like the MSR XGK-EX.

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The MSR Reactor in the alpine with the morning Alpenglow, where it belongs.


The Reactor is shorter and squatter than the Jetboil Flash, making it more stable. It is also less tippy than the tall Windburner. Even when filled completely and held at full extension for pouring, the Reactor's handle hinge showed no sign of flex. To our pleasant surprise, the Reactor's handle also makes for an excellent bottle opener.

As mentioned previously, unlike Jetboil models or the Windburner, the Reactor does not attach to the burner. This makes the whole Reactor system a little more prone to tipping over or falling apart, although it is easier to remove the pot from the heat source when it is about to boil over. It is much easier to move these stoves around when they are a single unit like the Jetboil models.

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Trish McGuire using the MSR Reactor and the Melitta Ready Set Joe to brew coffee while camping at Charlotte Dome.

Packed Size

We were disappointed to see that the Reactor's burner does not fit neatly into the 1L pot. It fits awkwardly into the pot, the valve handle sticking out preventing it from fitting in flush. If MSR made the burner slightly smaller and it could nest inside the bottom of the pot, there may be enough space for a 375g gas canister to fit on top. Everything does nest well inside the 1.7L pot, but this size makes the Reactor impractically large for the lightest of alpine pursuits and is more appropriate for two to four-person teams.

Best Application

If you're anticipating being outside when the weather gets bad, the Reactor is a great choice to bring along. It can handle itself at high winds and cold temperatures. It is a great snow melter. Alpine climbing, mountaineering, and backcountry ski trips are all great applications for the Reactor, especially if you want to boil water for more than 2 people with the 1.7 or 2.5L pots.

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The Reactor and the Hilleberg Jannu at 11,800ft.


The Reactor is expensive and retails for $189.95. Its burner is slightly larger than the Windburner (3.5 inches in vs. 3 inches in diameter). We think that the Windburner is a much better value and has better features, especially if you're looking for something in the 1L size. If you don't need something that performs in extreme weather, consider our Best Buy Award winning integrated canister stove, the Jetboil Flash.


The Reactor is near and dear to our hearts, and at one time was the only entirely windproof stove. Now competitors are creeping into the market and may eventually render the Reactor obsolete. We still think it is a great stove and will continue to bring it on our alpine missions, but the Windburner is just as efficient, weighs almost the same, and has a few advantages over the Reactor like its integrated pot and better lid system.

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Molly drinks from the MSR Reactor in the North Cascades, WA.

Other Versions and Accessories

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Reactor Stove System, 2.5L
  • 2.5L Pot with Reactor, ideal for 2+ people or snow melting
  • $220

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Reactor Stove System, 1.7L
  • 1.7L Pot with Reactor, ideal for 1-2 people and light and fast trips
  • $200

Reactor Hanging Kit
  • Stable and supportive hanging kit
  • Suspend the reactor from a single point
  • Ideal for big wall climbing or expeditions where cooking in the tent is required
  • $30

Strike Igniter
  • Truly the best way to light the reactor because the flame must penetrate the tip grating
  • $16
Jessica Haist

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OutdoorGearLab Member Reviews

Most recent review: September 3, 2015
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   Sep 3, 2015 - 10:03pm
johngenx · Climber
Something that I LOVE about this stove is one of it's so-called "weaknesses." The fact that the pot doesn't attach to the burner. When using a hanging kit (mine is a modded JetBoil one - lol) you can take the pot on and off the stove while the burner runs - making melting tons of snow super easy.

The wires from the hanging kit stabilize the pot, but you can still easily remove it, pour, and put it back on.

You'll have to pry the Reactor out of my cold, dead, hands. Oh, wait, I've got a nice hot drink thanks to my amazing stove!
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Running the Reactor on the Columbia Icefields in the Canadian Rockies. Hot drinks all day long!!

Bottom Line: Yes, I would recommend this product to a friend.
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