You're completely right, for my napkin-math, I ignored thermal conductivity. The low thermal conductivity of titanium has some advantages for camping cookware; you can often grab a titanium pot of boiling water from the exposed lip and not get horribly burnt, and the chances of scalding your lip on a hot cup of coffee are lower.

Back to the physics of it, doesn't thermal conductivity, along with most cases of heat transfer, depend on the length of the path?

Also, Fiets's idea of a heat diffuser for camping stoves is not a bad idea at all, most of them have an atrocious flame pattern. I think in all honestly, pan shape and flame pattern of the stove make more of a difference in efficiency than pan type. If your stove has a wide flame pattern, it can be maddening trying to use a narrow pot, most of the heat travels right up the sides and out into the world.

I am curious. What are the dimensions of the copper sheet, especially the thickness? What does it weigh? How well does it work?

Yes, heat transfer is dependent on length. The SI units are Watts/(meter*Kelvin). Aluminum has a thermal conductivity of 4 times cast iron and about 10 times that of titanium. Titanium pots work because they are thin. Any thicker and it would be an insulator.

Lightweight...and thin...aluminum cooksets are also harder to cook with because they are thin which is good for thermal mass but they are have a high thermal conductivity. The heat blows through them quickly and cooks the food in the pan faster than most people are used to, so that you end up burning food unless you are very careful.

Another way to look at this is that if you had 3 pans of equivalent thickness made of cast iron, titanium and aluminum, the aluminum pan would take less heat to get to temperature...it's 1/3 the mass of iron...but put more heat through to the cooking surface. Titanium would probably never transfer enough heat through the metal to do any useful work. If the aluminum and cast iron were the same mass, the aluminum would actually take more heat ( about twice as much) to get to temperature but it would put more of that heat through to the food. Forget about titanium in that thickness...unless you are planning a tour of the sun.

The problem with a heat diffuser is the same as with heating a cast iron pan. You still have to heat it which takes energy. A better solution would be to go with the JetBoil approach. JetBoil traps more of the heat from the flame by channeling the heat around the pan instead of just letting it escape to the surrounding. MSR makes a heat exchanger for the same purpose. I have one but seldom use it. It's bulky but it does trap some heat from your stove that would otherwise be lost.

I have been working on diffusers to get better heat dispersion with my titanium cookset. One problem that immediately became apparent is that thin camping cookware bottoms often get bends, bumps and heat warps. This makes for uneven contact between the diffuser plate and the pot and results in just moving hot and cold spots to different locations and with greater fuel consumption.

A side cutting can opener is my principle machining tool for my cat can alcohol stoves, so my first diffuser was an aluminum lid cut off a cat can. It of course had good heat transfer, but my “anemic, BTU challenged” alcohol stove melted the lid! So next I cut the top off a similar sized steel tuna can. It got red hot pretty fast but the flame reaching beyond the lid heated the pan's edges much hotter than the center, so my ultra-scientific test omelet was burnt at the outer edges and raw near the center, plus the above mentioned problems with the uneven pot surface. So I pretty much reversed the original heat distribution problem.

I am currently drilling holes and making test omelets using 28 oz. steel tomato can lids. The idea is to find the optimum number, size and placement of holes to get even flame distribution. It seems like a lot of hassle for a problem, which is easily solved by using an aluminum pot at 2 times the weight or cast iron at 2[SUP]n[/SUP] times. Is there a thermal engineer on the forum?

The one test material that seems to work very well is a square of fiberglass cloth. It can withstand my alcohol flame. I think a canister stove might melt it. It folds up easily and can’t weight more than a gram or two. The problem is the fiberglass has a very slack weave and wants to fall apart with repeated handling, making it a poor candidate for touring unless I can hem the edges. While the glass was a free scrap from my kayak repair kit, I am hesitant to spend the $25.00 for the high temperature thread, to sew a hem around a scrounged scrap of fiberglass, for a stove made out of recycled aluminum pet food cans. There is a cost symmetry that needs to be maintained for aesthetic values. (Sigh! I’ll probably buy the tread just to put my curiosity to rest.):rolleyes:

Personally I think the 'best' choice of cookware should be dictated by what you plan on cooking and by the number of people you need to cook for. If I was travelling alone in really warm weather I'd probably skip a stove altogether and go with tiffen containers and a cold menu. If I was travelling alone in cooler weather then I have a 5" heavy SS frying pan and a 5" heavy SS pot, a 1liter Thermos and a SS slcohol stove that I'd bring. Hot oatmeal, cheese omlettes, skillet corn bread, fried rice, steamed vegetables, coffee and hot chocolate I have no problems managing.

On the other hand - when I'm travelling with at least one other person, supplies are split up, and more possibilities open up. Personally I find things like blueberry pancakes, bacon and western omlettes, french toast, asperagus and mushroom crepes, scones, chicken fried rice, paella, trout or stir fried vegetables pretty much impossible to prepare efficiently or effectively in 'conventional' camping pots and pans.

Yeah - there are some people that don't expect to eat decently on tour unless its at a restaurant. I'm not one of those people. Ocassionally real whipped cream is nice with coffee or dessert and again - that might not be practical for one perspn travelling alone, but for two or more people travelling together - its not a big deal either. Just throw it in with the pack of frozen vegetables to keep cool and both get finished the same day before the cream even has a chance to get warm.

Really!

I've done a bouillabaisse for one before. I always carry a bit of saffron just in case the ingredients turn up near the end of the day.

I forgot that paella pans are dimpled to spread the heat more evenly. Quick some one grab their titanium pan, a center punch and a ball-peen hammer and tell us how it works.:D

Naaaah - back in the 1960 a guy by the name of Micheal Lax designed a line of cast iron cookware for Copco in Denmark. The stuff became design icons and vintage items are still sold today, but the company stopped making cast iron years ago. At the time I bought a complete set of matte black and can't even find examples of that color on the Internet. There were two sizes produced in the paella pan - the larger is perfect for 6 to 8 people; the smaller one for for 2 to four people and pne I have no issues packing in a pannier on ocassion. No dimples - just great performance.

Closest thing I've seen available on the market today is some stuff that comes out of the Oigen Foundry in Japan. Typically $150 to $200 for a cast iron pan, but the sloping sides and lack of protruding handles make them easy to use and store. The Copco stuff was particularly interesting because the pot lids all doubled as skillets.

Dry goods like spices, rice, lentils, bisquick and powdered milk have never been a problem to store or carry, but today, with the presence of so many convenience store, even things like Eggbeaters, frozen mixed vegetables, bacon, frozen shrimp and fresh chicken are stupidly easy to find. And if travelling in a group of two or three or four - even a cooler isn't required. In a waterproof bag the frozen stuff just keeps the rest fresh till its eaten - which typically is less than 4 hours later. Most of my cooking is done in the middle of the day in public park areas that double as a nice place to relax and enjoy the scenery, and is an important part of the 'tour'. In fact - if I was invited on any tour that was nothing more than an extended bicycle ride - I'd pass. I find trainers boring too.

Cooking efficiently and creatively on the road does require more planning than at home, but there are shortcuts that are very effective - they just need to be implimented. And I'm not interested in spending an afternoon cooking either - so believe me - 30 minutes is about the maximum I want to spend with a stove fired up. Eating - :lol: that's less of an issue.

Your stove is heat limited...unless you want to challenge a couple of hundred years of science. If you do that you might get some push back from engineers who use heat calculations based on that couple of hundred of years of science. Perhaps, before we go any further, you should go familiarize yourself with heat and temperature, which aren't the same thing. While you are there, look at heat capacity and thermal conductivity.

Also since you seem to be wanting to use an insulator to enhance heat transfer (:wtf:), you might also want to take a look at thermal insulation. Just a hint, you usually don't want to put insulation between a heat source and a cold body unless you are trying not to heat up the cold body.

If you're looking for ideas - the material used in this is very similar to what you're looking for, although the spproach is different. http://www.mec.ca/AST/ShopMEC/Hiking...ontent=Default

I have the SS diffuser plate on that set myself. Its OK but its also important to select a pan / pot size that will work optimally with the flame diameter and output of your stove. Those smaller burners are more effective with smaller diameter pots and pans.

A number of companies make stove-to-table items in sizes intended for individual servings. No reason to bring a 10" skillet if a 5" one will do a better job. Most aluminum ones are rated for a maximum of 400 degrees, SS multiply for 450 degrees. Le Creuset says their cast iron is OK at any temperature a home stove can generate and some specialty restaurants use bare cast iron almost red-hot to make fishes like blackened fish. Any camp stove will put out enough BTUs that it will require heat regulation to avoid burning food. Pressurized stoves are most popular with campers that primarily just want to boil water.

On the other hand, Reinhold Messner, probably one of the most famous mountaineers in history - regularly used an alcohol stove at altitudes over 8,000ft. I'm sure he had other options - that one obviously has advantages he liked.

My stove certainly is “heat limited” and thank God it is. I would say a better and more accurate description in terms of its intended use would be “heat sufficient.” I don’t need the BTU output of my Cajun Classic I use for crab boils and corn feeds at summer picnics to stir fry a few vegetables or steam a potato when solo touring. Or to make a one person paella for that matter. I can burn my morning oatmeal quite quickly if I don’t pay attention and turn the flame down to simmer.

I had a look at your Wikipedia links for heat and temperature and I think at a layperson’s level I can grasp the difference. Perhaps I didn’t describe the fiberglass clearly enough. It was a 4 oz per sq yd open filamented stranded woven glass cloth. The type of fiberglass that in this case was saturated with epoxy resin to cover a wooden kayak to protect the plywood when landing of a beach and the like. So the cloth is designed to “wet out” (be penetrated) quickly and completely with the relatively thick epoxy. So as I see it, regardless of the insulating properties of aluminum, steel and glass, the glass cloth allowed more heat (if I am using the term correctly) to reach the bottom of the pot and it did so while dispersing the heat more evenly over the pot’s bottom.

“When a path permeable only to heat is open between two bodies, energy always flows spontaneously as heat from a hotter body to a colder one.” What I think is missing in this Wiki definition for this situation is that the path has to be uniform and it is not when a typical camping pot with a banged up distorted bottom is placed on a flat metal sheet. On the other hand the pan is not dependent on contact with the glass cloth or the thermal conductance (new words for me) through the glass filaments themselves for heat to reach it. The flame, hot gasses or whatever the correct term is flows through the cloth touching the pot directly, but in a restricted manner. I have sourced a stainless steel cloth that might act in a similar manner to the fiberglass and would certainly be a lot more durable and I am sure could withstand the heat output of a canister camp stove. Stay tune and I will report back. :)

Let's leave the heat output alone.

If I am understanding your description of the fiberglass, you have a square of open weave fiberglass that is impregnated with an epoxy resin. I'm supposing that because the cloth wouldn't have any kind of rigidity. Let's start with the fiberglass. Fiber glass has a thermal conductivity of 0.04 W/mK. In real speak, that's damned low. Not much heat gets through it. Aluminum, on the other hand has a thermal conductivity of 205 W/mK or about 5000 times as much. Add in the epoxy and you have a pretty good pad to keep the heat from ever reaching the pot.

You also have to take into account that the epoxy is an organic based molecule that isn't all that heat resistant...some are but I doubt the one use for canoe repair is. It will start to pyrolyze at around 250 C (480 F). In practical terms that means it will start to stink. And then it will start to burn. And that would be bad. I would suggest that you test this stuff outside.

Now it is true that heat always, always, always flows from a hot body to the colder body. But it doesn't have to flow fast. With something like fiberglass, the rate at which the heat flows...the watts/meters* kelvin above...is very slow. That's the point. If the thermal conductivity is low, the substance is an insulator. The shape of the object makes little difference but the substance of the object does. In this case, the fiberglass won't act to speed the conductance of the heat from the flame to the pot but will act to slow it down and divert it. If you stop and think about this, there is a reason that we use fiberglass for insulation in our attics. It doesn't conduct heat very well. You could use your resin impregnated fiberglass cloth as a trivet because it will insulate real well. But you can't use it to enhance heat flow.

I'm not sure why people are looking for any kind of enhancement to conducting the heat from the stove to the pot in the first place. Anything stuck between the pot and the fire is going to require heat, i.e. stove energy, i.e. fuel, to heat it up. The aluminum of the pot will do a very admirable job of transferring the heat from the stove to the contents of the pot (sorry, but titanium isn't as good as aluminum no matter how much more you paid for the titanium:rolleyes:). The thinness of the aluminum is going to ensure that the heat moves quickly through it and not much of the heat is going to be wasted on heating up the metal of the pot.

Fascinating.

Even heat distribution and effeciency are things that cooks all over the world have obsessed over for as long as people have been putting food on the table. In the past 50 years mass production methods and metallurgical advances have resulted in pots and pans that are composites that combine the best advantages of each metal to produce products that have none of the weaknesses of any of them.

Its all been discussed many times by engineers that also cook, and is THE reason there's clad cookware on the market. http://www.cookingforengineers.com/a...ls-of-Cookware

So far I've never found any light-weight cookware specifically designed for camping that doesn't throw all that away and prioritize light weight at the expense of cooking performance. Exactly like cheap, thin kitchen pots and pans, it warps, burns food, loses any non-stick finish rapidly, and in the long run is most suitable only for boiling water. Thats ot just my opinion - you'll find lots of comments like that in reviews on outdoor sites like MEC or on some of the consumer reports publications.

So ultimately everything depends on priorities. People who are photography fanatics are going to pack a dslr and a bunch of lenses - regardless of what it weighs. People who feel the need to log everything online are going to pack a laptop, spare batteries, a charging unit, and more electronic paraphernalia than some others own. People who are obcessed about their bike are going to pack 20 lbs of tools and spare parts they'll probably never use. It happens - I've seen it all the time on the road. Some people insist on packing a gun (wonder how much THAT weighs!)

Point being - they went anyway - probably had a good trip and a lot of fun. Maybe they carried more than they should have - maybe they took things I wouldn't have. Why should any of that matter? Personally when I look back - I think about the places I got to see and some of the people I met. Don't ever remember looking back and agonizing over whether I would have had a better time if my load was a pound lighter or if I didn't have 'that extra two ounces of fuel'.

But YMMV and of course different things keep different people awake at night.

I remember, back in the days of film, having this same argument with my dad when taking a 4x5 and tripod and holders on a hike. Results showed the difference. Speaking of cameras.

I'm guessing it's not a matter of enhancing conduction, but of reducing hot spots. Sure, a thin aluminium pot on top of a Whisperlite will do an admirable job of transferring the heat from the stove to the contents of the pot: in fact, it'll happen so fast that the contents of the pot directly on top of the flame will scorch before the high-heat-capacity-food has a chance to transfer its energy to the surrounding food. By "wasting" energy to heat up the metal of a thicker pot or diffuser, you get the same amount of energy distributed over a larger area, resulting in more even cooking.

I'm not saying you can't cook rice in a thin pot on a Whisperlite, I'm just saying that it's very very tricky.

The Chinese have good results with a wok over very hot fire!

I understand the principle but doubt the practice. Putting a plate between the pot and the fire isn't the same as a cladding that is bound to the bottom of the pan. With only a loose connection between the two metal surfaces, the heat distribution to the pan is going to be minimal. If it weren't, we wouldn't use cladded pans at home but just a big distribution plate on our stoves. All a distribution plate on a camp stove is going to do is provide a way for the heat to be directed away from the pan (and food) to be radiated uselessly into the world. A 'distribution plate' made of fiberglass is going to be even more useless.

I agree...and have been arguing...that cooking with thin cookware is tricky. But that just means that the cook has to be more flexible in how they cook.

The thing here is to "focus" as much of the energy of the flame into the pot and eventually the food or water. I can see how something like the Jetboil's "heat exchanger" Fluxring concept might work, but for most stoves the critical thing is to keep the flame within the circumference of the pot's base and to use a good windscreen. Cranking up a stove so that the flames roar up aronud the sides of the pot might cook/boil things faster, but it will use more fuel than a smaller flame. Matching flame diameter to pot diameter and a good windscreen are two simple and critical factors to get right if you want to maximize the efficiency of your cooking system.

I agree but a flame diffuser or flame spreader works against your idea. The heat is going to go up and around your pot no matter what. That just the way heat flow works. It would be better to use something like the MSR heat exchanger to capture the rising heat that the stove puts out more efficiently then trying to spread the flame out more.

I think there are two competing ideas here; heat exchangers like the one made by MSR maximize the amount of heat flowing into the pot, while something like the heat spreader idea mentioned before is to make cooking a more enjoyable experience by ensuring even (if sub maximal) heating.

Try to fry a couple of eggs on a Jetboil and you'll see that the heat exchanger isn't always a good thing.

I'm arguing against a heat spreader and I've found a small flame that stays within the diameter of the pot's base to be the most efficient. A good close fitting windscreen can also enormously improve efficiency. IMHO a parabolic reflector/heat exchanger below the flame that the pot could sit on might be interesting to try in an effort to capture the heat of the flame that radiates away from the pot. Think of it as the stove's burner sitting at the focus of a reflective and conductive parabolic bowl that supports the pot at an efficient height for the flame. The metal bowl would have insulation on the outside to stop it from re-radiating heat away from the pot and would heat the pot by conduction and also by collimated infra red. Of course the pot/reflector system is a bigger thermal mass that has to get up to temperature, but I think more will be gained by capturing heat that currently escapes than by introducing something else to heat up.

Heat diffusers are nothing new and aren't just some camping accessory. Although most commonly used on home gas ranges, some people use them on electric ranges too. The most common material is cast iron, but specialty plates in copper are also made. A quick look on-line confirmed that the following companies market their own with their own lines of stoves for use AT HOME: Electrolux, Lacanche, Bosch, Kitchenaide, Whirlpool, Viking, Fulgor, Dacor and Bellacopper.

'Simmer plates' are also known as a 'French Plates' or 'heat diffusers' or ' burner plates'. Some of the descriptions?

FWIW: In my opinion most of this discussion about efficiency and all of the associated physics is interesting but largely irrelevant, to me at least. On my typical bike tour I really don't care about getting all of the heat into the food or using the least amount of fuel possible. I figure that when I can get fuel frequently and in smallish quantities, I am just not going to worry too much about using a bit more fuel.

If I can simmer at the cost of being a bit less fuel efficient, that is fine with me. I have not used a diffuser, but it looks like a useful item to me. I don't know if I will start using one myself, but I can see where they could be a plus. I guess that it starts to look attractive to me if it weighs less than a second burner specifically made for lower output (about 0.25 ounces).

My mistake. Sorry.

This is simply not the reality. Fiberglass has its weakness namely its structural weakness. It defuses heat as well or better than any metal defuser I have tried so far but I have more to try.

People have been using fire to cook food with for a pretty long time and I am pretty sure during the millennia before Revere Ware and All-Clad folks didn’t burn their food everyday. This insight jumped out at me as I was doing some testing of my camp cookware on my kitchen range.

I read Michael Chu’s article posted by Burton. For a layperson it was thermal engineering at a level I can more or less grasp – it is very well written. Chu describes the hot and cold area in gas burner and electric resistance coil ranges of the last part of the twentieth century. I however was doing my tests on a GLASS top range, which has very even heat distribution and heat modulation. Then I though back to the gas range my mother cooked on with its double flame rings on each burner opposed to the single flame ring on Chu’s example. I realized the clad and lined and plied pans we have been discussing were in answer to the specific deficiencies of twentieth century cooking technology. I remember cooking on a wood stove with its concentric removable burner rings that ensured even heating regardless of the pans diameter. Dutch ovens stacked with coals, Hawaiian gourds were used to boil taro with red hot lava rock tossed in, the cannibal caldrons complete with explorers ready to be boiled in so many cartoons all seemed to have solved the problem of even heat distribution. As near as I can tell everyone from paleolithic times until the second half of the twentieth century had heating harmony between flame and pot.

Nowhere is disharmony between pan and stove more pronounced than the backpacking ultra-light stove and pot. To test my vision I cooked an egg omelet in my 15/1000” thick titanium fry pan sitting on a half inch high pot stand over a glass top burner. If my insight was correct, it should cook as evenly as my well-seasoned enameled Calphalon cast iron skillet. The results, near perfection, where I was used to having a black charred middle and runny raw edges.

Then for the real test of truth, I cut out a scrap on fiberglass cloth and draped it over my alcohol stove and repeated the process in the ti pan again. Not quite perfection. I got a little charring on one edge but the omelet was cooked through from edge to edge. The design needs some improvement and fiberglass is not durable enough for camping but the concept is valid. The potential rewards: the weight of titanium, the durability and forgiveness of stainless, the heat distribution of aluminum, the non-reactive properties of Pyrex and the cooking prowess of cast iron. (Now is that too much to hope for?) So for me the conversation is no longer about the pot but about the stove.
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Recipe: 1 local, farm fresh, organic, pasture fed egg, a splash of rice milk, hefty pinch of basil, and 3 or 4 dashes of Cholula sauce cooked in extra virgin olive oil (EVO).