22g Stove - how much meths?

[Specialist Hoprocker]

I use a BB 22g stove for overnighters and the occasional cheeky brew whilst working on site. As such I've never run out of meths and have no idea how much to take on a multi-day trip.

I'm spending 4 nights in Scotland next month and i don't want to carry too much or too little. Over the trip i reckon i need:

8 x 300ml cups of coffee/tea.
3 x 550ml hot water for dehydrated food.

Plus a bit extra for the inevitable f*#kups.

I've got a 300ml meths bottle. Do we think that will be enough?

Ta muchly.

[whitestone]

Why not do a test boil of say 550ml water and then just use that as a multiple? Round up each time of course

A quick google suggests anywhere from 10ml - 20ml but the latter seems more common for 500ml boils so that would suggest your 300ml would do 15 boils and so "should" be enough.

[Specialist Hoprocker]

Thanks, good logic! I should have probably thought of doing that myself!

I'll get my syringe out and experiment.

[Specialist Hoprocker]

Experiment over. 20ml on a warmish day with no wind got 550ml hot but bot boiling. So i reckon 25-30ml for my set up.

[Alpinum]

Experiment over. 20ml on a warmish day with no wind got 550ml hot but bot boiling. So i reckon 25-30ml for my set up.

Seems about right. I reckon 30 mL for my self made cat food can stove. Comes with wind shield that fits the mug well. Will be enough also for cold water (close to freezing) in single digit degrees C. I try not to boil water thought. It takes a large amount of energy to heat water from 80 °C to boiling point (at sea level). Obv. the numbers shift the higher you go due to vapour pressure.
How many folks drink tea boiling hot? Take too little meths to heat water and add more if the flame goes out before it's hot enough. You can probably get away with 200 mL in this case.

[Bearbonesnorm]

Experiment over. 20ml on a warmish day with no wind got 550ml hot but bot boiling. So i reckon 25-30ml for my set up.

Are you using a good windshield?

[Specialist Hoprocker]

One of the best. Made by your good self...

[jameso]

8 x 300ml cups of coffee/tea.

I have a 60ml meths bottle that I get 4 or 5 x ~250ml morning brews out of - cowboy coffee made in a pot cosy mug insulator, water is heated the point when bubbles start to appear but it's not boiled. So 15ml per 250ml in average UK late spring-early autumn morning temps using a small mug with a windshield? All very approximate though it generally works out about right.

[whitestone]

Remember that most dehydrated foods don't need boiling water, they'll rehydrate with water at ambient temperature - it will just take a lot, lot, longer. So your 20ml of fuel will get the water hot enough to speed the process up.

Also tea tends to need water at or near boiling to break things down and get the best flavours (though my taste buds can't tell the difference) whereas coffee will brew at slightly lower temps - coffee nerds, I mean aficionados, will lambast you if it's not at 92.76495C or whatever but again I doubt most can tell the difference.

So as Gian says, just get the water hot enough to do the job.

[Specialist Hoprocker]

Thanks all. I'll let you know how it goes.

[riderdown]

My experience is that they don't like the cold. Used mine at bb200, worked great during the day, even for an evening brew. However when it got cold and I really needed a hot brew it would light fine but every time I put the cup on it it went out. Very frustrating as I got colder trying to get it to work.

[ledburner]

I think after a weekend use [m]aybe amount of meths you carry get disproportionally heavy , so gas stoves come in to their own. horses for courses ..see Joe's shop for a 'BRS hornet' type one really compact one.

[whitestone]

My experience is that they don't like the cold. Used mine at bb200, worked great during the day, even for an evening brew. However when it got cold and I really needed a hot brew it would light fine but every time I put the cup on it it went out. Very frustrating as I got colder trying to get it to work.

Yeah, meths is a bit particular about the cold (actually most fuel sources are, rocket propellants aside) but with a bit of forethought it's perfectly usable. I'll always shove the stove and fuel bottle as close to my skin as possible. Stoves like the 22g model and the homemade beer can ones don't have much thermal mass so get up to temperature pretty quickly. A small (100ml or so) fuel bottle will take a little longer but no more than a few minutes.

If you follow Shug Emery on YouTube (he's the hammocking guy) then he uses a meths stove for his morning Espresso in temperatures down to -30C, maybe even -40C so it is possible. I think he keeps the fuel bottle in a base/mid layer pocket all night. -6C is as cold as I've used mine.

[riderdown]

Yeah, meths is a bit particular about the cold (actually most fuel sources are, rocket propellants aside) but with a bit of forethought it's perfectly usable. I'll always shove the stove and fuel bottle as close to my skin as possible. Stoves like the 22g model and the homemade beer can ones don't have much thermal mass so get up to temperature pretty quickly. A small (100ml or so) fuel bottle will take a little longer but no more than a few minutes.

Water temperature seems more important, the stove lit and was flaming well, when the pot was placed it killed the flame straight away. The thermal mass of the cold water dominating the heat the stove had accumulated. A trangia style cooker would have not gone out as the pot would have been separate to the stove/fuel

[Bearlegged]

I once had problems with a cold stone floor sucking all the heat out of my stove. I used a bit of bark as an insulating mat and it started to play nicely. Tricky, isn't it?

[Alpinum]

Water temperature seems more important, the stove lit and was flaming well, when the pot was placed it killed the flame straight away. The thermal mass of the cold water dominating the heat the stove had accumulated. A trangia style cooker would have not gone out as the pot would have been separate to the stove/fuel

This^

For jet type meths stove, the meths needs to be warm enough (and produce a sufficiently high vapour pressure) to push the flames out of the jets. If a cold pot with cold water get set on it, the reduction of heat will reduce the vapour pressure and make the flames go out. Some tricks I've used over the years when being surprised by the cold with a meths stove:
- four small holes in the wind shield. Put two thin tent pegs (like super light Ti ones or something similar) through the holes to give a stand for the pot, so it doesn't sit on the stove, but 1 - 2 cm above it. If you forgot to make holes (or bring pegs), hold the pot above the stove, try not to burn fingers and keep it there for a couple of minutes 'till pot/water have warmed. Then put pot onto stove.
- warming of the fuel in a pocket when I start looking for a bivy spot.
- use of a small tin foil patch or even tin foil wrapped foam under the stove.
- use of a well sized wind shield. Right height and diameter/length to fit snug around the pots I use. As above, I make four holes and bring pegs when I expect temperatures to drop.

From personal experience I know that it's possible to have hot tea and supper from a meths at -16 °C. Yet, I'd not go as far as to say meths stoves are great in below freezing temps. Even less so for melting snow/ice.

[Mart]

I found if you spill a little on the outside before you light it then it acts as a preheat when cold.
Sometimes I used a little circular shaped foil to catch the overspill

[Specialist Hoprocker]

I use a little silver mince pie case to catch any spills and shield the stove from the ground. It works well.

[fatbikephil]

I use a little silver mince pie case to catch any spills and shield the stove from the ground. It works well.

My trick is to silicon the stove to a bean tin base (mines the 8g so needs some support) as it insulates the stove from the ground, if you slightly overfill a bit of meths will spill into the grooves in the tin and act as a pre-heater giving an almost instant flare; and sits nicely in a 450ml Ti cup.

[jameso]

I use a little silver mince pie case to catch any spills and shield the stove from the ground. It works well.

That's a good idea. I have a circular piece of Alu that stores in the base of the mug and then acts as a base to help stabilise the stove on uneven ground, a bit of meths on that as well as in the stove can help with getting it going. I think it acts more as a heatsink than a flat rock would but the pie case shape might be better for directing heat.