Canister fuel - how days would 16oz bottle last?

I'm planning to use canister fuel on few peaks over 20,000 feet, one of them is Denali. My stove of choice is MSR Reactor. If using stove to boil 24 oz of water - three times a day, by single person, how many days would 16oz bottle last?
From my research, it appears that I would need 4oz per day. So, 16oz canister used three times a day would last 4 days.
So, on 20 day trip, I would need 5 - 16oz bottles. Seems like alot.

From MSR

Mike wrote:

From MSR

Thanks Mike.

So, it's 1oz of fuel per 1 liter of water.

So, I'm going to assume here and say that I will boil 5 liters a day. That is 5 oz (on a perfect no wind day) a day.

20 day expedition will need (20 days X 5oz) = 100 oz.

100oz/16oz canister = 6.25 canisters.  

THAT IS ALOT.  WOW

Piotr 123 wrote:

So, I'm going to assume here and say that I will boil 5 liters a day. That is 5 oz (on a perfect no wind day) a day.

IMO that's A LOT of water for 1 person to boil a day. on all my major expeditions, we were boiling 2 - 2.5 liters / person / day (breakfast and dinner). I think this is part of your issue...

Why Reactor and why not liquid fuel stove?
Watch this https://youtu.be/TCXvBpM9PsI if you haven't watched yet. According these guys you need 8 oz of liquid fuel per person per day.
8 oz x 20 = 160oz which is 1.25 gl but from what I read/heard 1gl per person is enough.

Georgy Gobozov wrote:

Why Reactor and why not liquid fuel stove?
Watch this https://youtu.be/TCXvBpM9PsI if you haven't watched yet. According these guys you need 8 oz of liquid fuel per person per day.
8 oz x 20 = 160oz which is 1.25 gl but from what I read/heard 1gl per person is enough.

Thanks for the info.  The whole goal was to save some weight, by brining canisters.  However, it won't be the case.  I would need alot of canisters.  I guess I will bring my SOTO Storm Breaker stove.  

A canister stove is handy if you are in a bivouac or to brew up on route but a white gas stove is better for camping especially in Alaska where quality white gas is  readily available. In South America/Asia quality clean liquid gas can be difficult to find and you might need to use kerosene so having a stove with optional jets is important. As are plenty of spare parts.

It appears that MSR makes a stove called Wind Burner Dou.

https://www.msrgear.com/stoves/stove-systems/windburner-duo-stove-system/10366.html

Question is:  If the pressure is low, would there be a problem to simply tip-over the canister, so fuel flows down?  

I think that would be a benefit compared to Reactor.  Again, when temps and pressure is low.

Piotr 123 wrote:

Question is:  If the pressure is low, would there be a problem to simply tip-over the canister, so fuel flows down?  

i don't really get your question. if the pressure is low, the canister is out of fuel. that stoves burns gas, not liquid...

curt86iroc wrote:

i don't really get your question. if the pressure is low, the canister is out of fuel. that stoves burns gas, not liquid...

Sorry.  Let me explain.  Some people say that canisters don't work in cold temperatures. 

Therefore; I'm wondering if WindBurner Duo would help solve that problem, by tilting the canister up-side-down, where the black valve is on the bottom.  So, flow of fuel is moved by gravity. 

Piotr 123 wrote:

It appears that MSR makes a stove called Wind Burner Dou.

https://www.msrgear.com/stoves/stove-systems/windburner-duo-stove-system/10366.html

Question is:  If the pressure is low, would there be a problem to simply tip-over the canister, so fuel flows down?  

I think that would be a benefit compared to Reactor.  Again, when temps and pressure is low.

The danger is that you'll get a flareup that shoots flames up the side of the pot, trashing the insulating wrapper (ask me how I know this). Some stoves (WindPro, Whisperlite Universal, others) have a pre-heating loop in the fuel line that ensures that the fuel will be in a vapor state when it exits the burner. These stoves can be run with the canister tipped or inverted, making them a good choice for winter use or for getting as much fuel as possible out of the canister. The Windburners and the Reactor do not have this feature, and I don't know how practical it would be to combine a preheat loop with MSR's burner-pot interface. I think the best way to use any Windburner or Reactor in cold temperatures is to find some way to keep the cartridge warm (body heat, warm water bath, various dangerous tricks).

Curt86iroc, it's true that these stoves burn gas. The fuel is packed into the cartridge at a high enough pressure that most of it liquifies, resulting in a canister with mostly liquid fuel in it, and a layer of gas under high pressure at the top of the canister (boiling point of any substance varies with the pressure on that substance). When the valve is opened, the vaporized gas escapes, reducing the pressure in the canister and sharply reducing the amount of liquid fuel, which reduces the pressure in the canister even more. Eventually the pressure drops to the point where none of the fuel is in liquid form, and soon after that the pressure drops to where gravity keeps the fuel from leaving the canister at a rate that will let you cook your food or boil water. At this point tipping or inverting the canister would probably improve the flow of gas, but at the risk of a flareup as I described earlier. 

mark felber wrote:

Some stoves (WindPro, Whisperlite Universal, others) have a pre-heating loop in the fuel line that ensures that the fuel will be in a vapor state when it exits the burner. These stoves can be run with the canister tipped or inverted... The Windburners and the Reactor do not have this feature, and I don't know how practical it would be to combine a preheat loop with MSR's burner-pot interface.

That's the crux of the issue. The only stoves on the market that are intended to be used in inverted canister mode are all open-flame stoves, without a built-in heat exchanger or windshield. Of course you can use them with your own heat exchanger and windshield, but they won't be as efficient as a WindBurner or Reactor. Cooking times will be longer, and you'll have to carry more fuel. On balance my choice would be a WindBurner/Reactor, and use a water bath if it gets really cold.

From personal experience, gas canisters are just a major pain in cold temps. I've been on two cold trips in CO in the last two years. Trying to boil water at 0 F at about 12,000 ft just wasn't happening with a canister that was only half empty. The flame was so small that the pot cooled off just as quickly as it was being heated. I've seen some solutions discussed on this forum such as insulating the canister and having the canister in a water bath, but those options seem questionable to me. It gets worse as your canister is more empty, so you would end up carrying around a bunch of not-quite empty canisters. My partner on my last trip carried two canisters. She kept one in her jacket while using the other, and then swapped them when the flame became weak. That seems an Ok solution if you are just doing some quick snow melts and boiling water, but it would be inconenient for doing longer burns for cooking or melting snow for a larger party.

The water bath works quite well until the water in the bath freezes, at which point you've got a canister caked in ice. Insulating the canister won't do much, the canister cools itself as the pressure inside it drops (go back to high school chemistry for an explanation of this). I've done a couple cold trips with a remote canister/liquid feed stove (MSR WindPro) in the last few years. The stove worked about as well as a Dragonfly or Whisperlite, without the hassle of pumping but at distinctly higher fuel cost. The best reason I can find to use a gas canister stove at temps below 20 F is if you're in a part of the world where white gas is hard to find and cartridges are plentiful, which I understand to be the case in most of Europe.

Jonathan S wrote:

From personal experience, gas canisters are just a major pain in cold temps. I've been on two cold trips in CO in the last two years. Trying to boil water at 0 F at about 12,000 ft just wasn't happening with a canister that was only half empty. 

as long as you keep you canister insulated (i.e. in your sleeping bag etc.) you should never have this problem. I've used canisters at 19k with air temps well below 0F without issue. 

Atmospheric pressure at 19K is going to be quite a bit lower than at 12K, so the boiling point of the fuel is going to be lower, and the pressure differential between the canister's contents and outside air is going to be greater. It's not surprising that your canisters worked well at that altitude, but I wouldn't expect similar performance at 12K. Were you in a tent? A snow cave? Cooking in the open?

mark felber wrote:

Atmospheric pressure at 19K is going to be quite a bit lower than at 12K, so the boiling point of the fuel is going to be lower, and the pressure differential between the canister's contents and outside air is going to be greater. It's not surprising that your canisters worked well at that altitude, but I wouldn't expect similar performance at 12K. Were you in a tent? A snow cave? Cooking in the open?

the temperature of the canister and gas has more on an effect on its functionality than altitude. keep it insulated and you will be fine. if you don't believe me, there are plenty of articles out there on this topic.

yes, we were in a tent and we cooked in it (well ventilated of course). my climbing partner exclusively uses isobutane canisters on 8000m peaks without issue.

A water bath works wonders.

Use white gas on Denali unless you want to bring canisters for a few day push on something technical.

White gas on Denali is SOP. If you need some on the West Buttress you will find some. If you have extra on the way down, fill up folks bottles up while they are out carrying a load.

Interesting that when watching 8,000 meter expeditions, I would say everyone uses canisters.  If canister is good (and it works) on 8,000 meter expedition, why not Denali?  Is it related to "pressure"?  

Altitude isn't an issue with canisters. Cold is, but this can be mitigated with the usual tricks (warm it up in your jacket, use a water bath). And the advantage is easy set up, cooking in vestibule/tent more safely if need be.

The issue is more a practical one. 

1) A Reactor works great melting snow but not so much if you want to cook something that isn't freeze dried. Most people probably enjoy having a few "real" meals over the course of a 3wk expedition, even folks who happily suffer on shorter trips. If you want to eat Mountain House (or PB&J) for 3 weeks that's on you.

2) as Allen mentioned, there's just going to be plenty of white gas up there if your math doesn't work out perfectly and you run low. Gonna be harder getting the few people with canisters to part with one. Maybe the trends are changing and everyone will be running a Reactor in 2021 but I doubt it.