The "Magic" of the Caldera Cone

OK, so the Caldera Cone is an efficient alcohol stove system. But why is the Caldera Cone so efficient?



In today's blog post, I take a quick look at The "Magic" of the Caldera Cone

HJ

P.S. This is the last installment in my series on the Caldera Cone. I promise that I will move on to other topics although I may review some other Trail Designs equipment at some future point.

In case you missed any of the series:

• Caldera Cone Alcohol Stove Review (on Seattle Backpackers Magazine)
• Caldera Cone Review Supplement -- Additional Photos and Technical Appendix with Weights
• Caldera Cone vs. Clikstand Alcohol Stove Tests
• The Caldera Cone's 12-10 Burner
• What "Color" is your Caldera?
• The "Magic" of the Caldera Cone (Why is the Caldera Cone so efficient?)

The caldera is a similar but much improved idea to this one (scroll to stove 6).

I was recently thinking about re-trying the idea only this time using titanium instead of a candy tin. It would be interesting to compare the tin to the caldera to see how much of a difference there is.

Thanks for this. It's been fun and informative.

Annie

Perry: Thanks for posting that link. I've been too busy to read it yet! Ack! Maybe this weekend.

Annie: Glad you liked the posts. I think it really is a good system for those looking to go light.

HJ

I just found and ordered two more canteen cup stoves to add to my collection. One is for the US military canteen cup, another for a British army canteen cup.

From what I gather about the Caldera stove from reading about it online (never actually saw or used one).
*It requries some assembly before use.
*It is a windscreen and stand, but not a stove.
*It leaves the forest floor unprotected.
*However, it is probably very efficient.

There are a couple of things I like about canteen cup style of stove.
*Minimal assembly (appeals to my occasional sense of lazy, er, simplicity).
*Pot stores inside stove, thus helping to prevent debris from *getting in the pot.
*Some versions protect the floor, though some don't.

My next version will be to use two titanium pots, one nested inside the other, similar to stove 6 mentioned earlier. This can be used with solid fuel (hexamine or even twigs) or with an alcohol burner. I will have to drill air holes and support wire holes in the outer pot but it should be very light, around 3-4 ounces. This is for a combination solid fuel stove, windscreen, and stand.

I was actually thinking about all this a month or so ago after not having tinkered with it a while, but now you've motivated me to work on it a little more.

The CC doesn't require much assembly. Just slide one side of the dovetail joint into the other and then set the pot on top. Not bad at all compared to say a Whisperlite or something like that. About the same level of effort maybe as a gas stove, although on gas stoves you can vary the flame whereas a CC is just on or off.

You are right, there is no protection for the forest floor. I've had very few problems. Heat rises.

I wouldn't run it in dry chaparral though! Find a clear spot, a sandy creek bed, a rock, etc. No biggie.

Canteen cup stoves are OK, but heavy and typically not very efficient.

Sounds like you've got some kind of DIY rig in the works, yes?

HJ

I should have been clearer. I like the canteen cup style, that is, nesting the pot in the stove/windscreen. The stoves themselves are heavy and generally inefficient.

Here is my plan for the next long weekend.
I will use the same titanium pot and wing stove, the same amount of fuel (whatever brand of hexamine is on sale), the same conditions (my garage), water from the fridge (same temp), etc. The change will be different shapes and configurations of stove/windscreen to see what works best. I will try to fabricate the sidewalls of heavy aluminum foil. This is to tes tthe concept and shape. Eventually I will get appropriately sized titanium pots to make a durable version of the stove.

Variables
1. no windscreen, wing stove only
2. replicate more or less the Caldera
3. windscreen to the top of the pot but not snug to the pot (the Caldera appears snug)
4. windscreen halfway up the side of the pot
5. windscreen to the bottom of the pot (see if the hot air is funnelled straight up with any efficiency)
6. then try bottom ventilation options

Maybe you could try the same and we could compare notes.

I anticpate the caldera is the most efficient, but if even the half way up the pot works almost as well, it would be preferable for me and my desire for simplicity (laziness).

I suspect the Caldera will be the most efficient. The beauty of the Caldera is that the windscreen is also the stove support. I have the compact Caldera with the MLD 850 ml pot. It is NOT as efficient as the full length Calderas.

Ringtail,

Do you have a photo or two of your set up?

HJ

HJ,

That is like asking for a picture of Jay Leno's car.

The stoves that I use are the Caldara Cone with MSR Titan Kettle and a Caldera Cone with 600 ml Evernew wide pot.

I would be embarassed to list all the stoves I own.

Wanna bet?

Yeah, not embarrassed: "Bragging rights" as a collector!

CM

How about your top ten?

You Caldera Cone type rigs for starters.

HJ

More than you wanted to know.

In order of use:

Caldera Cone with 600 ml Evernew pot:
Pros:
The Caldera Cone fits into the 3 cup Ziploc,
Wide pan is THE most fuel efficient of all the Caldera Cones,
No pot lifters needed,
Very stable..
Cons:
Takes two burns to boil 12 oz. for food and 8 oz. for beverage.

I use a 16 oz. solo cup inside the 3 cup Ziploc with cozy to do freezer bag cooking. After hydration the bag can be turned down over the sides to make eating easier. I use a JetBoil spoon.

Caldera Cone with Trangia 28:
Pros:
This kit will FRY food!!!!!,
The Caldera Cone fits into the 3 cup Ziploc,
Very stable with pot,
Cons:
The skillet is a bit unstable,
Need to use pot lifters.

This is the kit I use when cooking in the pot and frying. Yes, Rand will make one if you ask.

Caldera Cone with MSR Titan Kettle:
Pros:
Can boil enough water for both food and beverage,
Very stable,
No pot lifters needed,
The design of the Titan Kettle is classic and aesthetically pleasing.
Cons:
The Caldera Cone does not fit into the 3 cup Ziploc,
Pot handles tend to get hot.

The solo cup and JetBoil spoon are also a part of this kit.

This is the Ti Caldera Cone complete wood burning setup. The firebox is big enough that it does not require constant attention. This is the stove I use when I want to primarily use alcohol, but have the option of melting snow.

Trangia 27-5:
Pros:
Stove is elevated so it can be used on picnic tables,
Use a metal shovel for a base and cook on the snow,
Very stable,
Very wind proof,
Reliable - no moving parts.
Cons:
Heavy,
Need to carry the burner and fuel in pocket,
27.0 oz.,
Need pot lifter.

This is the stove I use to cook lunch when nordic skiing. A fun stove to use.

GSI Minimalist pot and V8 stove:
Pros:
The pot lid works well as a beverage lid,
Has a new and innovative pot lifter,
Inexpensive,
Needs a very small flat area to set up.
Cons:
Not as fuel efficient as a Caldera,
Needs a pot lifter.

Made a replacement cozy for the pot from a ccf pad. Used when I want to make a cuppa on day hikes. Just a simple hardware cloth stand and Al flashing windscreen.

Optimus Nova:
Pros:
High BTU output,
Simmers well,
Robust all weather stove,
High energy per ounce content of the fuel,
Field repairable,
No plastic components,
Good for melting snow.
Cons:
Heavy - the stove alone weighs more than my normal complete kitchen,
Fuel is not environmentally friendly,
Priming is time consuming, messy and maybe dangerous.

I have owned MSR Whisperlite, DragonFly and SimmerLite but had a plastic pump failure and cooked over a camp fire for two nights. Now use an Optimus Nova for winter overnights.

Snow Peak Giga Power with piezo - 3.7 oz.:
Pros:
Easy to use,
Simmers well,
Easy on/off makes it fairly fuel efficient,
Two or three people can share this stove conveniently.

Cons:
High profile is unstable,
Wind screen is difficult,
Small flame pattern makes hot spots on the pan,
Empty fuel canisters are not environmentally friendly,
Need to keep the canisters warm in below freezing temperatures.

IMHO the selection of the gas canister blend is more important than the stove. I look for canisters with a high percentage of propane and isobutane rather than regular butane.

Current test stove:

Emberlit-UL wood burner.

Stoves I do not use and why - in no particular order.

Caldera Cone and antigravity 3 cup pot - kept at the office to cook lunch.

Fosters Caldera Cone - nice little setup but wider pots perform better with only small weight penalty and the system is a little fussy to setup and take down.

Ultralight Outfitter Fosters can System - nice stove and has the burner off the ground, but wider pots perform better with only small weight penalty.

Compact Caldera Cone with Mountain Laurel Designs 850 ml pot - nice set up but less fuel efficient the full sized Caldera Cone and the tent stakes used for the pot support are a bit fussy.

Bushbuddy Ultra with Snow Peak 900 ml pot - nice stove, but the small fire box requires constant tending to melt snow.

Four Dog Bushcooker LT with Vargo Ti Lite Mug - nice stove that works well but the fire box is even smaller than the Bushbuddy Ultra.

T’s Side B stove - works great, but unstable.

Brasslite Turbo I - adequate stove, but unstable.

PackaFeather FeatherFire stove - best temperature control I have ever seen on an alcohol stove, but that is not a feature that I use.

Brasslite 600 ml Caldera Cone - nice system, but the Evernew 600 ml has the same features, but the wider pot performs better.

That's it? Good start. I need to try a few more different alky stoves, but I like the kerosene stoves very much, like a Optimus 111T, 8R's etc. and the roar of a old MSR stove.
Duane

Nice list! And thanks for taking the time to list out all the features. I've never had the time to really try out wood stoves although I think they'd be fascinating. I'd love to try one of Devin Montgomery's Backcountry Boilers. Interesting insight on the size of the fire box. Do you use the Inferno option on your Ti cone?

How do you like your FeatherFire? I've always thought that would be an interesting stove to test.

HJ

If any of us wanted to quit we could start a support group. Do you suppose "stoves anonymous" has been taken.

Thank you hikerduane, you made me feel better.

Me too!!!!



Yes, the Inferno option works great!!



I like your reviews. They are a real service to the backpacking community. PM me your address and I will loan you the stove if you will do a trail report.

Hay, I have a weigh with wurds. Nice alky list, I want to expand sometime. I picked up a Caldera Cone for a REI .9 ti pot last summer before my vacation, loved it on my 8 day trip. Very consistant.
Duane

PM Sent!!

HJ

Just posted something on the FeatherFire in a separate thread here on TLB in Lite Gear Talk.

HJ

I have never used a Caldera Cone before but decided to buy one to try it out. We use the Backcountry Titanium Cookset 1650ml. Looking forward to how this works with that pot

Make sure you get the right sized cone for your pot of course. Good luck and let us know how it goes!

HJ

I did get the right cone for the pot I have. I haven't had time to do anything but to unpack and look at it. It is a little hard to roll back up and put it in the container though. Hopefully it gets easier the more you use it. Has anyone went with a larger container to put it back in?

Ewker,

I've used a ZipLoc container from the grocery store.


It has pluses and minuses. I actually did a blog post on the subject if you're interested: What "Color" is your Caldera? .

HJ

Jim,

based on the cone I have I would need the larger sized Ziploc container. The one in your picture looks like a medium. So far I haven't found a large container made by Ziploc

How tall is your cone?

HJ

I don't have it with me but it sticks out of the Medium size ziploc container (like the one in your picture) by 1/2" to 1"

That sounds normal. Mine sticks out 5/8". I then fit the lid of the Ziploc over the rim of the cone. It's sufficient protection.

My Caldera Cone in a Ziploc container:


I examine the various options in What "Color" is your Caldera? if you're interested.

HJ

I hadn't noticed that picture showing your cone sticks out of the container. That looks about how far mine is sticking out. I will have to double check once I get home to see if it fits inside the top like you show.

I do like the Ziploc container more than the one that comes with the cone. If my foster pot set will fit in that one I will swap it out

It works pretty well even though it sticks out. The Ziploc is a better fit in my opinion for a rolled cone, the Ziploc is easier to clean, and of course the Ziploc is cheap.

HJ

Lat night I finally got around to try out the cone and stove with my pot. I noticed that the pot is a little hard placing it in the cone. I had to put the pot in the cone then sit it all over the stove. Does this get easier the more you use it?

The pot we use is a 1650ml which is for 2 of us. I put 3 cups of cold water (from the fridge) in the pot. I read the direction which calls for 15 to 20ml of fuel for 2 cups of water. I put 30ml of fuel in the stove and fired it up. I place the cone/pot over the stove and waited. The water never got to a boil. It got hot but not boiling. I wanted to try it again with 40ml of fuel but we had the grandkids dropped off so I had to stop. Hopefully I can get out there tonight to see if the 40ml of fuel will work.

It's a little bit fiddly to get the pot into the cone, but you get used to it. In some ways it's nice since I can pick up my pot and cone as a unit by just grabbing the handles on the pot. I can move it over as a unit and use my Sierra cup to snuff the flames out.

I usually figure about 25ml of HEET for 500ml of water. Usually less works, particularly if I'm using a higher ethanol content fuel, but 25ml always gets two cups to boil. 35ml will probably work for you, and 40ml should definitely do it.

HJ

I'm a big fan of the Caldera Cone. Have migrated to the Ti-Tri versions so that I can use a twig fire as backup if I run out of alcohol or Esbit, or if I am melting snow in the winter. I have two, one that fits my larger 1.3L Evernew and one that fits my Stanco aluminum greasepot (and also fits a 900ml Evernew BTW).

Hi, Rob,

I tried out a Ti version for the first time a few weeks ago. It was really nice to be able to use wood.

The Ti-Tri Caldera Cone



HJ

after using the Caldera Cone this weekend I am not impressed with it. It took 70ml of fuel to boil 40 ounces of water. That is not effective IMO. I will be cooking for two people so I am beginning to think a canister stove is going to be the best option for us.

That's odd. That seems unusually high for a Caldera Cone.

I use a Caldera Cone with a 850ml MSR Titan kettle with a tight lid. I can easily boil 16 fl oz of water with 18ml of green denatured alcohol or 24ml of HEET. Proportionally, it should only take about 45ml - 60ml to boil 40 fl oz of water, depending on what kind of fuel you're using. Your fuel usage sounds a little high.

What kind of fuel are you using? Do you have any photos of your set up in use?

You're boiling 5 cups at a time (1.25 qt) it sounds like. That is a bit more than the average alcohol stove user. Usually, when I boil that much at once I take a stove that uses a petroleum based fuel.

HJ

I am using denatued alcohol and the pot I use is a Titanium 1650ml pot. This pot is larger than what most people use but I am cooking/boiling water for 2 people.

Is it a tall, narrow pot?

HJ

http://www.backcountry.com/backcountry-titanium-cookset-1650ml

Pot Dimensions:14.5 x 8 cm
Fry Pan Dimensions:14 x 3 cm

OK, obviously not a tall, narrow pot. Worth asking, though, since a narrow pot can have wasted flames going up, around the sides.

Not sure why you're having to use so much alcohol. Like I say, if I'm going to be regularly boiling more than a liter or so, I'll typically switch to a fuel other than alcohol (wood, white gas, or canister gas usually).

HJ

I am thinking about trying a different alcohol stove (old whitebox) and seeing how it works compared to the one supplied with the cone. I have nothing to lose by it. I may send an email to traildesigns and tell him how it is working and see if he has any ideas.

A Whitebox stove is typically faster but also usually requires more fuel.

HJ

can't be any worse that now...just sayin

lol. Well, I'll be curious to hear how it goes.

HJ

And you might indeed want to talk to the guys at Trail Designs. Rand is usually really helpful.

HJ

I sent him one this morning

I got a reply back from Rand.

"That isn't an unreasonable amount of fuel for 5 cups. Alcohol doesn't have as high a heat content as petroleum fuels.....and while the Caldera Cone maximizes the use of the available heat and minimizes wind effect.....so is the best alcohol solution out there.....in the end, it is still limited by the amount of heat available in the source alcohol."

I assume you're using the stove made for the cone, but at that much water you may be past the point of diminishing returns.

What brand denatured are you using and is it fresh? You might try some Yellow HEET just to be sure.

I assume you're using the frypan lid?

The titanium also doesn't help in this case since it doesn't transfer heat as well as AL.

If you still can't get it to work, I'd remove your drink water from it and boil just your food water first and then boil your drink water while letting your food hydrate. 2 smaller boils are usually more efficient on fuel (if you don't have to prime any) than one bigger one, regardless of stove type. I've had a Windpro that couldn't boil 3 quarts when I was testing some worst case stuff.

topshot,

Yes i am using the stove that came with the cone. I do cover the pot with the frying pan lid so it keeps the heat in.

I use either Crown or S-L-X denatured alcohol. Can't remember which brand I have now. I have thought about going back to the Yellow bottle of Heet. I think it is better to use.

Your idea of boiling the water for meals then drinks is a good idea. Guess I just want to get it over with at one time. We are going out again so i will give that a try and see how that works out.

Hopefully, that will work much better for you. I'd still try some Heet if it doesn't just to be sure.

I don't know how TD does its cone design - if they work solely on only fitting the diameter of the pot without regard for water volume or take volume into account also. It could be they made this stove TOO efficient (e.g., slow-burning). You can do that with even small amounts of water. The stove will burn a long time on little fuel, but never reach a boil because there's not enough heat for the amount of water. It could be you need a stove that burns a bit faster.

Denatured alcohol in the US is generally a blend of ethanol and methanol. HEET is methanol. Ethanol has a higher heat content than methanol. In other words, denatured will burn slightly hotter than HEET. If you're not getting enough heat out of denatured, you're generally not going to see any improvement by switching to HEET.

That's actually a fallacy. Yes, Al conducts heat better, but Ti is far stronger. Ti pots can be made that are much thinner (and therefore lighter). A thin walled Ti pot will heat water with about as much efficiency as a thicker walled Al pot.

Uh, no. One large boil will be more efficient in terms of total number of grams of fuel. It may be more practical to break it up into two boils, but it will not be mroe efficient.

HJ

I haven't noticed the Ti products being significantly thinner than AL. I'm sure they are but it's not very noticeable.

I'll stand by my experience that 2 smaller boils are more efficient. Your mileage has obviously varied. I should have qualified it more - I'm talking larger volumes needing to be boiled where the stove is having trouble putting out enough heat.

Take a look at a periodic table of the elements some time. You'll see that titanium actually weighs more than aluminum. So how do you use a heavier material but wind up with a pot that is lighter overall? You make it thinner. Titanium is so strong that you can get away with it. It isn't going to be noticible to the eye though.

HJ

I agree that an alcohol stove may not be the best stove for two people. I NEVER boil more than 20 oz. Efficiency drops off with any boil more than 16 oz.

I've been learning about working with titanium recently and apparently the rule of thumb when using Ti to replace Al is to use half the thickness and adjust, often thinner yet, from there.

I have the Caldera Cone Ti-Tri for the REI .9L pan. The titanium cone rolls up and fits inside the pan along with a small fuel bottle, small plastic measuring cup I scavenged from a Pepto Bismol bottle, fire steel and the 12-10 stove. No need for matches or a Bic, because the 12-10 fires right up with the fire steel.

I think titanium is a better, but more expensive, material for the cone than aluminum. It doesn't get as beat up as the aluminum one. And you can keep that titanium rolled up until the cows come home, but as soon as you take it out of the pan, it snaps into a nice round symmetrical cone.

With the Ti-Tri,the pan is not supported by the top of the cone, but sits on two titanium tent stakes which run through the cone. In fact, the top of the pot sits above the top of the cone a little. It has to be that way because the cone is smaller to fit inside the pot.

Some thermal efficiency is probably lost because the pot extends above the cone a little, but it packs up very nicely. You have to remember not to forget the titanium tent stakes however, and there is a chance you could lose them on a backpacking trip. I guess nothing is perfect.

I pack the tent stakes in a tent stake bag along with a long handled spoon which then goes in my food bag. The stakes won't fit inside the pot.