I just tested out my caldera for the first time. I'm in Seattle, so at sea level. For 2 cups tap temp water it took me 8:45 to bring to a boil. I used just a hair under 1tsp ever clear and fuel ran dry right at boil. A couple questions.

1- is 8:45 about normal boil time?
2- how much longer will it be, say at 6000 feet?

Thanks! I'm loving this stove! By by jetboil & snow peak.

it will depend on your exact set up.
With my TiTri/ 550ml pot I get 500ml to boil between 7 and 8 minutes , about 7:30 at around 15c (59f)
(about 14g used , that is a bit under one fluid ounce)
Try starting with more fuel and then snuff the flame out when you get a boil.
For some reason it appears to work better that way for me and it also means I don't have to start the stove again in adverse (colder) conditions.
You make a "snuffer" by moulding some aluminium kitchen foil (doubled up if thin) over the burner, cutting around the bottom so that it just slides over the 10-12.
You then just drop it on the burner , that will snuff the flame, when cool (10-20 seconds...) turn the two upside down so that you can recover the extra fuel.
Franco

It sort'a depends on your tap water. I get right around 6 minutes with a 10/12 and about 5/8oz of SLX (Methanol/Ethanol blende) at ~1000 feet using a Kmart Grease Pot and a CC. Closer to 8-9 minutes with esbit and 3/4 of a tab. Tap water is 40F or ~4.4C.

It seems you are getting a longer burn time with much greater fuel efficiency.

Generally, altitude, up to about 8000-10000 won't make a heck of a lot of difference. Less oxygen, slower burn, but it will boil at a somewhat lower temp. I am guessing that your fuel efficiency will go down a bit, though...it usually does out in the field. I am also guessing that you will need some fuel to prime the stove. Not usually required at sea level and at higher temps.

I can boil 2 cups of water in 5-6 minutes on mine. I live at 4800ft. I was using a wind screen and an ounce of denatured alcohol.

"I am also guessing that you will need some fuel to prime the stove."

Shouldn't need to prime anything for alcohol. Priming is more for compressed gas type stove.

My experience has been that you have two offsetting factors. One the boiling point drops off and two the stove tends to burn slower (and maybe more efficiently). On my own system, I was able to boil 2 cups of water on a 1/2 oz at 12,000 feet. the time to boil was about the same as at 1000 feet. Best regards - Jon

I'm surprised no one has mentioned the 'other' factor in etOH boils: water boils at about 2*F less for every 1000 ft you go up in elevation. So at 7k ASL, you'll see 'boil' at about 198F. I've made food at 13.5K and even with a roiling boil in the pot, it was barely hot enough to cozy-cook dinner. The water was probably only 185-186*.

Since an alcohol stove only puts out one amount of BTU's, you'll see quicker boil times as you go up, but not necessarily a better efficiency.

I used my CC for the first field trip, last August. I tried it at home first, elevation around 3800'. Boil time for 1.5 cups of water were the same at 9,000'+, I believe a little over 7 minutes for me, using 5/8-3/4 oz alky, .9 REI ti pot. I'll be out for a week starting Friday AM in the Mammoth Lakes area. I always recovered un-used fuel.
Duane