gnat vs. jetboil

[M B]

In anticipation of possibly not being allowed to use alcohol next summer on the JMT, Ive been playing with my Gnat a bit.

For this, I may use a stainless steel 10cm cup that weighs 2.03 oz. With lid its 2.2 oz.

So I did some test boiling 16 oz water (weighed). With high heat, It rolling boils in 2.5 minutes on 0.27 oz fuel. But on very low heat, it reaches boil in about 9 minutes on 0.18 oz fuel.

Big difference by waiting a few minutes.

So, I calculated up how many boils I could get out of a 100gm cannister that way. = 19.5
A single 100gm cannister will work for me for the JMT.= :)

So, I wondered how a jetboil would compare to this. Note, I dont own one.

Jetboil says they basically average 0.14 oz fuel per 2 cup boil. Not that great really, but it is much faster, which is worth something in groups for sure.

On a total weight basis, a jetboil would be 8.5 oz+8 oz for 100gm cannister and fuel = 16.5 oz to boil about 25 2-cup boils.

For the same weight with my gnat and SS cup, 3.9 oz + larger 12oz cannister/fuel = 15.9 oz, but could boil 8/.18= 44 2-cup boils.

Jetboil loses. Even at 0.1 oz per boil the jetboil still loses.

This surprised me because fuel efficiency on long trips was the reason many cite for carrying a jetboil. Yes its fuel efficient when used to heat fast. But not enough to make up for the weight it seems if you heat slow with a UL cannister setup.

[James holden]

the folks at BPL have already done all the math and testing in the 2011 SOTM

http://www.backpackinglight.com/cgi-bin/backpackinglight/2011_sotmr_integrated_canister_stoves.html

read it

;)

[Jeremy and Angela]

That's a lovely chart Eric, but what do the numbers represent?

(I assume higher is better, as wind appears to lower them.)

[James holden]

lets just say its a certain amount of water boiled

i suggest signing up to view the full BPL article

;)

[Greg Mihalik]

Table 4:
"Comparative gas mileage (number of pints/approx. 0.5 L of water that can be boiled from a single 8-ounce/227-g fuel canister) for eight canister stoves in four conditions."

[M B]

Hmmm.

Dont see that they tested my setup on as low of heat, and compared boils vs. total carried weight at all.

If you do, please point me to it.

And wind is not an issue.
As an avid alcohol stove user, I know how to minimize wind impact.
In bad conditions, it involves encircling my stove and pot with a sleeping pad.

Fuel conservation is a priority, because I dont bring extra.

The fuel usage for the gnat is 22% higher on low, and 34% on higher on high than what I found. Obviously the high was higher than mine, I dont turn up all way, no reason, and the lower was also higher.

[Christopher Kuzak]

I know this isn't scientific, but I get about 14 or so uses out of my Jetboil (Sol Ti now) from one of the small canisters. Looking at the check marks on my canisters (how I keep track), I know for sure I'll get 12. That's pretty good given altitude, wind, etc.

[James holden]

Dont see that they tested my setup on as low of heat, and compared boils vs. total carried weight at all.

they tested MODERATE heat on the gnat …

note that neither you nor BPL did an apples to apples comparison … youre both "testing" FULL ON jetboil fuel use against LOW/MODERATE gnat fuel efficiency

i suspect that at lower settings the jetboil becomes even more fuel efficient

;)

[M B]

My understanding, never having owned or used one, is that the jetboil doesnt go real low, at least it didnt at one time. People complained they couldnt simmer. I recall reading somewhere where someone figured out how to do it, but said it wasnt easy.

My windscreen for the gnat/cannister is water bottles, food bag, rocks, logs, natural items, depression in ground, and as a last resort…sleeping pad. No extra weight needed.

The only thing I care about is weight carried vs boils. And all I do is boil water. Usually 1.5 cups.

"they tested MODERATE heat on the gnat .."

They should have tested a bit lower, on par with alcohol.

[USA Duane Hall]

What temp was the water in your tests with the Gnat? Close to Sierra Nevada water temperatures? I'll bet not. Good fuel conservation.
Duane

[James holden]

My understanding, never having owned or used one, is that the jetboil doesnt go real low, at least it didnt at one time. People complained they couldnt simmer

my jetboil gets REAL low

it simmers just fine

if youre going to make a comparison i suggest borrowing a jetboil and testing the fuel usage under the exact same conditions …

just like BPL did (well the should have tested the jetboil at moderate heat too)

testing conditions can vary, so i wouldnt put too much stock on the claimed fuel usage jetboil or even BPL claims, as your conditions that you test your stove under could be different in temperature, altitude, canister pressure, pot type, etc …

i also suggest testing it with a household fan with your makeshift windscreen and seeing how much fuel usage goes up ….

like i said BPL tested this 2 years ago … and they do these tests better than anyone else ive seen on the intrawebs so far

in short they found ~ a 30% fuel savings in jetboils at FULL BLAST when compared to a gnat at "moderate" heat …

as to whether it was "low" enough … its your call whether to wait 2 min for water vs "9 min" and still use less fuel with the jetboil …

;)

[M B]

Water was 65 F

Wont matter, I will stick a full 100gm cannister in resupply bucket anyway. And I probably would boil on high too, just because it wont matter. But in a pinch, nice to know how much the fuel consumption can be reduced by slowing it down.

Up till know, I only used the gnat with a 1.3L pot for 2 persons, preferring alcohol even for 2P. But given the uncertainty of fire restrictions , figured Id better at least be prepared to take a cannister.

[Greg Mihalik]

MB,

This Thread, and John's blog, addresses a similar question. Note that his systems are all modified, and his water volumes are somewhat "non-standard".But, most importantly, he Knows where his numbers come from for the conditions typical for him.

Note that when he used 24 grams of esbit per days the "cross over occurred at Day 9.

Build a spreadsheet, use numbers for Your conditions and requirements, and see what happens.

[M B]

Actually, I have no desire to do any more comparison.

I already know for the hiking I do, a jetboil will never pan out, being too bulky, and heavy.

At best, fuel efficiency per weight carried even on high,using BPL #s would put the jetboil ON PAR with the gnat

This is because for the same weight, I can carry a 220gm cannister instead of a 100 gm
Thats 25 days between resupply. Double what I ever suspect I would.

On LOW, I have no fear of using my 1.05 oz Zelph flat bottom pot with a gnat either, as it has a steel bottom.

[James holden]

so basically no real "comparison" was done …

you will note that on HIGH the jetboil blows the gnat away by almost half the fuel use even in calm warm conditions …

BPL themselves said

Some people claim that an integrated canister stove’s fuel savings offsets the stove’s additional weight compared to a lighter weight combination of a top-mount stove and titanium cook pot. Let’s look at some numbers. The stripped down Jetboil Sol Ti Premium Cooking System weighs 7.5 ounces (213 g); the Monatauk Gnat weighs 1.6 ounces (48 g), and an ultralight titanium cook pot with volume equivalent to the Jetboil Sol Ti weighs 3.1 ounces (88 g), for a total of 4.7 ounces (144 g), a difference of 2.8 ounces (79 g). From our gas mileage calculations for Warm/Calm conditions, we estimate that the Jetboil Sol Ti will boil 29 pints of water from a 4-ounce (113 g) fuel canister, while the Monatauk Gnat will boil only 18.5 pints. If we assume a need for four pints of water boiled per person per day, then a 4-ounce (113 g) fuel canister would support two people for 2.3 cooking days with the Monatauk Gnat versus 3.7 cooking days using the stripped Jetboil Sol Ti. The comparison comes out as a tie because of the fuel canister – in both cases you would likely take along a full fuel canister, so there is no savings in weight carried. The only time you could save weight in this comparison is when you can get by with a smaller size canister of fuel or you are using the stove to boil water for a group.

there are many other reasons to use the jetboil … thats a persons choice whether to do so or not …

but if i were to make a "comparison" of say 2 down jackets … or any other 2 pieces of gear … i should probably have both pieces in hand and have tested both personally

;)

[M B]

Im not doing any comparison.

Please show me a graph of WEIGHT CARRIED vs. TOTAL BOILS that includes the jetboil and real UL cannister setups. I dont see any. But I suspect for the short trips most take, if they took a partial cannister, the jetboil would not look good.

An issue I had with the BPL comparisons involving alcohol, is they will test some absurdly heavy popular item instead of the lowest possible weight setup, then make a chart that showed the crossover point at 4-5 days. My crossover point for alcohol vs cannister is 2 weeks.

No offense to any users of popular alcohol items, but when you can have a cannister setup, including fuel container, that weighs less than your alcohol setup, something doesnt make sense.

I totally agree there are reasons to carry a jetboil.

However, I am a minimialist when it comes to stoves. It is only used for a paltry 20% of my food, and I find it almost ridiculous to bring at all. Thats why my alcohol setup is 2.5 oz with empty fuel bottle. I am not worried in the least of running out of fuel, or not having hot water. If I run low on fuel, you use warm water instead of hot for several days, or eat crunchy food. Its simply not a big deal.

The weight carried, is, to me.

[James holden]

sure you are as implied through the thread title … perhaps a better title would be "testing of gnat"?

we can make a chart that shows the weight and daily usage of a gnat setup vs. a jetboil using the BPL data …

its not that hard … any BPLers interested?

when everyone gets into arguments about partial canisters, its honestly time to stop worrying about a few grams here and there

personally i thing this concluding statement on the BPL review says it all ..

Using this reasoning, which we admit is a bit of a rationalization, the integrated stove comes out at least equal, or on top under certain conditions. If our reasoning is valid, this is the first time it can be successfully argued that an integrated canister fuel stove is a lighter weight option than a conventional canister stove plus a cook pot. And the integrated stove offers some serious convenience as well. In any amount of wind, the integrated stove will completely blow away (pun intended) the conventional stove. It’s worth it for that reason alone.

;)

[M B]

"Using this reasoning, which we admit is a bit of a rationalization, the integrated stove comes out at least equal, or on top under certain conditions. If our reasoning is valid, this is the first time it can be successfully argued that an integrated canister fuel stove is a lighter weight option than a conventional canister stove plus a cook pot. And the integrated stove offers some serious convenience as well. In any amount of wind, the integrated stove will completely blow away (pun intended) the conventional stove. It’s worth it for that reason alone."

I suppose everyone should carry a Hilleberg tent too, all the time?
Or driver a 4 wheel drive all the time?
Or bring down booties and down pants all the time?

Of course not.

The statement is wrong. An item is only worth it, if its actually needed.

$150 because you might cook on a windy day?
Extra weight carried on normal length trips because you might cook on windy day?

Ill eat my noodles crunchy, but you know what?, I havent had to yet:)

[James holden]

worth depends on the person … but its probably some BPL conspiracy to sell more jetboils =P

mr jordan said in the same thread …

The Jetboil SOL Ti offers significant advantages over the Gnat, or another lightweight system.

The advantages aren't clear until you use the system.

I think its greatest advantage is the simplicity of the setup, and the aesthetic of its integrated pieces.

Obviously there are practical advantages as well.

In a trek to the Canadian Rockies this summer, my partner and I shared it for a week of foul weather. We boiled 30 pots of water on a single 100g fuel canister in conditions that averaged 45 degrees, windy, and rainy. Not fooling around with windscreens, and otherwise waiting long times for water to boil was great.

For the ease and efficiency of our system (8.5 oz of hardware and 6.5 oz of fuel + 2 oz each for a mug, bowl, and spoon), it was hard to beat for a 2-man cook kit.

On 7/23 I posted to my Twitter account after I returned from Canada: "…The stove I always hoped Jetboil would make. A fantastic burner for one or two alpinists."

I was excited to see Will's data validate my field experience.

Really, give this little stove a try. It's phenomenal.

And, when you compare it to a setup required for 2 people to share an alcohol, or Esbit stove for 30×0.7L pots of water (esp. in cold, wet, windy weather)…it's almost hard to justify any other method of hydrocarbon cooking on efficiency, or ease of use considerations at least.

im willing to make a comparison chart from the BPL numbers and see what they come up with …

we just need to use a "stripped" system of the same pot size for an apples to apples comparison … we can compare the jetboil on HIGH vs the gnat on both MODERATE and HIGH …

but if we dont add the windscreen weight in, then we should mix the numbers from both the WARM/CALM and WARM/WIND fuel efficiency …

;)

[M B]

I totally agree it has its place, and that it offer some great benefits to some situations. Particularly multi-person.

But I dont think it belongs in everyones pack. Nor do I think there is any singular item of any kind that belongs in anyones pack. Hikers, locations, and trips are all too different to make broad sweeping generalizations.

What I do think, is a much lighter cannister stove that is ONLY designed for boiling 2 cup small pots instead of 1-2L pots, is very possible to make, probably weighing under one ounce, if someone had the desire to do so. Even the gnat is an overbuilt beast of a stove for what a solo hiker needs in good conditions.

[James holden]

what people use is totally up to them …

ive considered getting a new fire maple horne and a very small AL cup for places where fuel efficiency is of no concern, but being able to survive a few days in a snow cave is … for climbs where being able to make water means youll live, and where every gram counts

well see if i buy one

ill make the chart this coming week …

what i need is

the lightest jetboil setup possible using the same pot size and not modifying the burner or anything else that might affect the boil time/efficiency in any way … BPL has it at 213g for the SOL Ti

the lightest version possible of the gnat + an MSR titan pot (thats the pot they used for the test so lets stick with it, its pretty light anyways) but WITHOUT the lid, and i need the weight of a foil lid

also i need the weight of the lightest PRACTICAL windscreen that will withstand a 10 km wind (BPL tests were done with an 8 km wind) … and wind at such levels is not uncommon in alpine areas … no dumping out the gear or using rocks etc… theres plenty of places where this might not be practical … and honestly the weight will likely be minimal

im quite interested in what the numbers say myself

note that this is from BPL data …

one thing to note is that if you are using alot of fuel, boiling every day for weeks/months at a time … the 30-50% fuel savings may be a financial consideration as well … sure the SOL AL/TI are expensive … but the jetboil zip which BPL tested at basically the same weight and fuel efficiency as the SOL AL is 60-80$ …

http://www.spadout.com/p/jetboil-zip/

;)

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