Jetboil Joule Review - Part 1, Overview

The Jetboil Joule is a high-volume cooking system that performs very well in ambient conditions; however more testing in cold conditions is needed to asses its overall performance.

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by Ryan Jordan | 2014-07-15 00:00:00-06

Overview

The Jetboil Joule cooking system is a liquid-feed canister, high-volume cooking system.

Liquid feed canister systems take advantage of the canister in an inverted configuration to deliver liquid fuel to the burner, in contrast to upright canister systems, which deliver fuel as vaporized gas to the burner.

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The Jetboil Joule is an inverted canister, liquid-feed, integrated stove system that includes a 2.5L pot with an integrated heat exchanger.

The primary advantage of a liquid feed canister system is that it offers better cold weather performance, since the vapor pressure in the canister isn’t changing while the stove is operating.

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In the Jetboil Joule system, the canister is inverted, with the liquid feed tube exiting from the bottom of the stove and controlled by the wire valve. The entire canister-fuel delivery/control unit is contained in a cage that provides stability, as well as simplicity of form and function. Most inverted canister stove systems require the canister to be remotely detached from the stove unit.

In upright canister systems, as the vapor pressure in the canister decreases, the canister temperature decreases, and the rate of fuel delivery to the burner decreases.

Thus, upright canister systems don’t work so well in the cold, or for boiling large volumes of water at cooler ambient temperatures.

The Jetboil Joule attempts to solve this problem not only by inverting the canister, but also by preheating the liquid fuel before it hits the burner, which allows it to maintain power in cold temperatures.

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The tube that feeds liquid fuel to the burner is preheated by the burner, thus vaporizing the fuel as it leaves the burner head for efficient combustion. This design is commonly used in other liquid fuel (e.g., white gas) stoves.

In addition to the inverted canister configuration and the preheated liquid fuel delivery tube, the Jetboil Joule pot has an integrated heat exchanger, which allows for more efficient heating of the pot, and greater fuel efficiency.

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The Joule offers a 2.5L pot with an integrated heat exchanger. Our testing has shown time and again that integrated heat exchangers that have large surface areas with the heat exchanger fins in direct contact with the cooking pot bottom offer significant fuel efficiency gains.

The other unique feature of the Jetboil Joule is that it’s an integrated system that consists only of two parts - the stove base and the pot - which connect to each other to make one solid unit during operation.

There are no separate parts such as windscreens, fuel pumps, or external heat exchangers, and the entire stove unit - with an attached fuel canister, nests neatly into the pot for space efficient storage.

Features & Specifications

The approximate pot volume of the Jetboil Joule is 2.5 L - just about the right size for melting snow for a 2 or 3 person cook group, or for three season cooking with groups of 3 to 5 people.

Not including the weight of fuel canisters, we verified the weight of the entire system (stove base + pot) as 27.6 oz.

Table 1. System Specifications (Comparison of Jetboil Joule & MSR Reactor 2.5L System)

Stove WeightPot WeightTotal System WeightNominal Water Capacity [1]Inside Pot Dimensions
MSR Reactor 2.5L6.3 oz14.9 oz21.2 oz72 oz (2.1 L)6.875 in (dia) x 4.375 in (height)
Jetboil Joule11.7 oz15.9 oz27.6 oz88 oz (2.6 L)6.125 in (dia) x 6.0 in (height)

[1] Nominal water capacity was calculated as the amount of water that the pot can hold up to a point 0.75 in below the top rim of the pot.

Other features of note include a lid that serves as a pasta strainer, a silicone-coated folding handle that contains the system when packed away, a piezo-electric igniter, a neoprene pot cozy that helps the system retain heat during cooking, and enough fine fuel line control to be able to simmer foods at low heat.

Using the Stove

Using the Jetboil Joule simply involves removing the stove base, attaching a fuel canister, filling the pot with water, attaching the pot to the stove base, opening the fuel line valve, and clicking the piezo-electric igniter to light the stove.

Setup is even easier the second time around, because the fuel canister can remain attached to the stove base until it empties and needs to be changed out with a new canister.

Baseline Fuel Efficiency

Let’s compare the Jetboil Joule with another integrated canister stove system, the MSR Reactor with its 2.5 L pot (note that the Reactor system is an upright, or gas-feed system, as opposed to the Joule, which is an inverted, or liquid-feed system).

For the purpose of this baseline test, both system pots were filled with 72 oz (2.1 L) of 55 deg F tap water. The test was performed indoors at an ambient temperature of 65 deg F. Boil times represent the time to a rolling boil. The tests were performed at an altitude of 4,750 feet above sea level. All other test procedures were based on the test description in the Lightweight Stove Systems for Group Cooking series. See Table 2 for the results.

Table 2. Baseline Comparison of the Jetboil Joule and MSR Reactor: Boil Time & Fuel Efficiency

Water Volume Boiled (L)Boil Time (mm:ss)Fuel Consumed (g)Canister Capacity (# Pots Boiled Per 8 oz net Canister)Fuel Efficiency (g of fuel consumed per L boiled)
MSR Reactor72 oz (2.1 L)12:3020 g11.4 pots (23.9 L)9.5 g / L
Jetboil Joule72 oz (2.1 L)5:4520 g11.4 pots (23.9 L)9.5 g / L

Observations

  1. The Jetboil Joule is a much louder stove than the MSR Reactor. At a distance of 12 inches from the burner head, noise was measured at 78 dB for the Joule and 53 dB for the Reactor (ambient sound in the space where the testing was performed was measured as 49 dB).
  2. Both stove systems required the same amount of fuel to boil the same amount of water. This indicates that they have comparable efficiencies (i.e., when efficiency is defined as the amount of fuel consumed for a given amount of water boiled).
  3. The Jetboil Joule is a powerhouse of a stove. Its boil time was less than half that of the MSR Reactor system.
  4. In the mild and warm test environment of an indoor kitchen, it’s clear that the Jetboil Joule offers a huge operating efficiency advantage (as defined by decreased boil times relative to the MSR Reactor system). In theory, because the Reactor is an upright (gas feed) canister system, and the Joule is an inverted (liquid feed) canister system, these differences should be even more pronounced at cold temperatures and other scenarios where boil times may be extended (e.g., melting snow). Future testing will explore the Joule’s cold weather performance.

Preliminary Assessment

I have to admit that I was pleasantly shocked by the Joule’s operating efficiency. A blisteringly fast boil time for a large volume of water, a system that was easy to setup and operate, and nesting storage that allowed the fuel canister to remain attached are its strong points.

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The canister can remain attached to the stove unit and stowed inside the pot for simple storage and easy setup the next time it’s used.

We’ll reserve our review rating pending long term testing of cold weather performance, a more detailed evaluation of the stove’s design, engineering, and construction, and consideration of its carbon monoxide production.

But for now, there’s a lot to like about the simplicity and fast boil times from the Jetboil Joule, especially for group cooking that requires larger water volumes.


Citation

"Jetboil Joule Review - Part 1, Overview," by Ryan Jordan. BackpackingLight.com (ISSN 1537-0364).
http://backpackinglight.com/cgi-bin/backpackinglight/jetboil-joule-jordan-review-part-1.html, 2014-07-15 00:00:00-06.

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Jetboil Joule Review - Part 1, Overview
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Maia
(maia) - MLife

Locale: Rocky Mountains
Jetboil Joule Review - Part 1, Overview on 07/15/2014 14:00:04 MDT Print View

Companion forum thread to:

Jetboil Joule Review - Part 1, Overview

James Marco
(jamesdmarco) - MLife

Locale: Finger Lakes
Jetboil Joule Review - Part 1, Overview on 07/15/2014 14:57:58 MDT Print View

I don't think I will be getting one antime soon. 27oz+ is way too heavy.

Greg Mihalik
(greg23) - M

Locale: Colorado
Re: Jetboil Joule Review - Part 1, Overview on 07/15/2014 15:04:01 MDT Print View

^^^^
But not to bad if you're with 5 others doing group cooking.

It's the right tool for that job.
But that's not My job.

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: Re: Jetboil Joule Review - Part 1, Overview on 07/15/2014 17:03:33 MDT Print View

and in the winter when the inverted canister would be very useful

James Marco
(jamesdmarco) - MLife

Locale: Finger Lakes
Re: Re: Jetboil Joule Review - Part 1, Overview on 07/15/2014 17:50:57 MDT Print View

Ya know, I usually only go with myself and sometimes one other person I call me.

Phil Barton
(flyfast) - MLife

Locale: Oklahoma
Re: JetBoil Joule on 07/16/2014 10:30:06 MDT Print View

Wow. It's a bit expensive too. $200 at http://www.rei.com/product/868190/jetboil-joule-group-cooking-system

Jeff McWilliams
(jjmcwill) - M

Locale: Midwest
Re: Price on 07/16/2014 10:39:06 MDT Print View

Meh.

Roger Caffin's inverted canister stove cost me $144.00, and I still need to supply my own pot (such as the Primus ETA 1.8L pot for $55.00)

The MSR Reactor is also a $200.00 stove.

An MSR Dragonfly white gas stove would cost $140.00. A Primus 1.8L ETA heat exchanger pot would cost an additional $55.00

I'd say this is right in line with similar products on the market designed for winter use.

Eric Blumensaadt
(Danepacker) - MLife

Locale: Mojave Desert
EFFICIENCY?? on 07/16/2014 14:32:15 MDT Print View

How does its fuel efficiency compare to other canister stoves?

THAT'S the real question for longer group trips.

Joel Benford
(Morte66) - F - M

Locale: Surrey flatlands, England
Re: EFFICIENCY?? on 07/16/2014 15:45:54 MDT Print View

9.5g of gas for a liter of water seems pretty good. My cheapo gas stove uses 7g for half a liter.

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: EFFICIENCY?? on 07/16/2014 15:50:51 MDT Print View

From Roger's article http://www.backpackinglight.com/cgi-bin/backpackinglight/canister_stove_efficiency_p3.html

average upright canister stove was 11.6 g/L, four Jetboil models were between 8.5 and 9.5 g/L, Reactor was 10.5 g/L

From this (Ryan's) article Jetboil and Reactor were 9.5 g/L

So Roger and Ryan are pretty consistent on the Jetboil (although Roger didn't measure the inverted Jetboil). Roger measured Reactor 10% higher than Ryan.

In Roger's article, the Jetboils used about 20% less fuel than average upright.

You got to read the article - has a bunch of different stoves...

I think this measurement is tricky. Hard to compare two different experimenters - any difference might just be the way they measured it. Roger's measurement where he uses same test set-up to measure different stoves is more valid.

James Marco
(jamesdmarco) - MLife

Locale: Finger Lakes
Re: Re: EFFICIENCY?? on 07/16/2014 17:03:45 MDT Print View

There are a lot of variables that can effect the efficiency numbers. Oxygen content of the air will effect the efficiency of the burns. Humidity. Ambient temperature. Surface you put the stove on. Height of the burner/pot. Etc... 10% is within tolerance. I usually give these numbers a spread, min, max and average. I call 15% a significant deviation to account for the crudity of most tests. For example, depending on weather you have a burner on high, medium or low, but there is no set definition for these terms. People eyeball the medium setting. High is the maximum for a stove, but this can vary between 4500BTU and 11000BTU. Low can sit there forever without boiling a liter of water, yeilding inconclusive results. Some stoves will not run evenly on lower settings (Simmerlite for example.) And, how low is low? Too low will drive *up* fuel consumption.

I usually try for a 10-12 minute burn for a half liter. This usually produces the best fuel efficiency. Longer means more heat is radiated out. A 20 minute burn for one liter is barely tolerable, though. If you want a 10 minute burn, you will use more fuel. This is assuming all else remains the same: pot, lid, distance, heat screen, etc. For 2 Liters, the numbers can get worse. At least with the Joule, it will make a good cold weather stove(<20F) for a larger group(>4 people.) I think this is where Ryan is headed with this. For me, myself and I, well, we have no use for it. But it is interesting to read about these little toys.

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: Re: Re: EFFICIENCY?? on 07/16/2014 17:23:47 MDT Print View

Yeah

Roger's stove is probably better for really cold temps. If you don't want to fiddle with putting canister in a bath of water or ... It weighs less and you'll never make up for the added weight with improved efficiency on the Jetboil

For 1/2 liter or 1 pint, I figure 3 minutes on fairly high, or turn to medium and it takes 5 minutes but saves 10% of the fuel


"For me, myself and I, well, we have no use for it."

Interesting how many solo hikers there are on BPL. Reaction to working in "the Dilbert world"?

James Couch
(JBC) - M

Locale: Cascade Mountains
Re: Jetboil Joule Review - Part 1, Overview on 07/16/2014 18:36:47 MDT Print View

I will be very interested in seeing how the Joule actually performs in cold weather. It could well be the ultimate snow melting machine! The time difference with the Reactor shown here is astounding.

Tjaard Breeuwer
(Tjaard) - MLife

Locale: Minnesota, USA
Winter use on 08/12/2014 07:23:26 MDT Print View

The other feature that seems promising for winter use is that the burner is high above the ground, so you could hopefully use a less heat resistant stove base as well as having less melting of the snow under the stove.
It also looks like it could work well as a hanging stove.

The big question for me when looking at the design is how well the flame control works in cold weather, since it is on the liquid fuel line, not on the vaporized part at the top.
However, for winter use I don't do a lot of simmering or fine cooking, so as long as it can be turned down far enough to prevent the snow from scorching, it's acceptable to me.

Edited by Tjaard on 08/12/2014 07:27:14 MDT.

Santiago Vazquez-Gonzalez
(iago) - MLife

Locale: Boston & Galicia, Spain
Hanging kit with windscreen on 10/25/2014 05:19:40 MDT Print View

There's an alpinist hanging kit for $20 that includes a windscreen. Would also be interesting to see if the wind screen afects CO2 performance.

http://www.jetboil.com/Products/Joule-Alpinist-Kit/

Edited by iago on 10/25/2014 06:54:46 MDT.