Kelly Kettle Laboratory Performance, Preliminary Evaluation

Le 13 janvier 2004, par Schwert,

The purpose is to determine the operating characteristics and performance of the Kelly Kettle in a controlled environment.

Introduction :

The Kelly Kettle is a unique water boiler that is essentially a water jacketed double walled aluminum chimney with a removable aluminum fire pan. To use, a small fire is built in the pan, the water filled chimney is placed on top and the fire heats the jacketed water. The scanned images 1 and 2 show the Kelly Kettle’s operating principle and normal use, respectively.

This evaluation was carried out in a standard kitchen laboratory using a natural gas fired stovetop as the source of fire. This preliminary evaluation was undertaken for two purposes ; to familiarize the test personnel with the operating characteristics of the Kelly Kettle ; and to determine the operating performance in a controlled test environment.

Materials and Methods :

The Kelly Kettle is available in two sizes from the manufacturer, a 2.5 pint and a 1 pint version. This evaluation used the 1 pint Kelly Kettle. Volume determinations were performed using a standard plastic volumetric vessel commonly known as a measuring cup. This volumetric vessel was marked with both standard US fluid ounces and SI liters. Volumetric precision was estimated to be within +/-½ ounce. Starting temperature of the water was determined with a calibrated thermometer with ½ degree Celsius precision. Boil times were determined with an analog split timer precise to 1/5 sec. Boil was determined by visual observation of the water in the Kettle’s spout. Boil was determined to be achieved when the first signs of large, full-rolling bubbles appeared. Heat source was a natural gas stovetop burner running at maximum heat output. See image 3 for experimental materials.

Results :

The absolute maximum volume of the 1 pint Kelly Kettle was determined to be 24 US fluid ounces (700mL) to the base of the spout. In actual use the volume used should not be greater than 20-22 ounces as the boiling water splashes out of the vessel. All boil determinations were done using 20 ounce fills (600mL). This is the UK standard pint size.

Five boil tests were run. The first boil was done using 24 ounces of water and was not timed. A fair amount of grey residue was present in the water. Kelly Kettle instructions recommend the first boil be discarded to remove residual sealant. The next four boils were done using 20 ounces of 15degC water (59degF) with the gas flame at maximum output. The resultant boil times were : 6 min 20 sec, 6 min 35 sec, 6 min 20 sec, and 6 min 24 sec. This is an average of 6 min 25 sec, with a standard deviation of +/- 7 sec.

Discussion :

The Kelly Kettle is a well made device. The spun aluminum container, fire pan, and fittings including handle and cork are well fitted. The aluminum rolled crimp at the top and bottom of the vessel are smooth and clean. The rivets holding the handle bail and cork chain are smooth and did not leak at any time during the 5 boil tests. The instructions warn that these may leak initially but seal themselves over time. The bottom rolled joint did leak a fair amount on all boil tests. During the initial 2 minutes of heating this joint leaked about ½ ounce of water (14 mL). This may be an artifact of the heating method (gas stove vs. fire) but this is an area of concern as this much water leaking into the fire pan could be detrimental to the fire. This is an area of test for field performance experiments. See images 4 and 5.

Manipulation of the Kettle over an open fire is an important aspect to learn for safe and efficient use. The handle bail naturally places the holding hand over the top vent of the chimney. Placing the Kettle over the flame for the first boil resulted in all the little hairs on the fingers being melted off. An appreciable amount of heat is essentially directed up through the chimney and remarkably focused on the fingers. This resulted in a very rapid re-understanding of the laws of thermodynamics. The handle bail needs to be held at a 90 degree angle to the Kettle to prevent such catastrophic removal of finger hairs. Even though the tester was aware of this handling requirement, he still had to "learn" it.

Overall Impressions :

This is a unique boiling device, with appeal as the light weight package (a bit over a pound) allows brew ups without carrying fuel, stove, pans etc. Further testing will determine the efficiency using small wood fires and specifically look at the leakage issues from the bottom rolled seam. It is possible that the boiling times using a wood fire will be appreciably different as the fire pan and/or the turbulent nature of a wood fire may change the heat transfer properties. It is also possible that the rolled seal which sits on the fire pan will not be heated in the same manner and the leakage will change. These tests were primarily done to determine the operating characteristics and may have little similarity to actual field use.

On a further note, the eclectic nature of the device is also personally appealing. See also this story for both mood and proper "handling" (pun intended).

Kelly Kettle, Flame On !

The Kelly Kettle adventure continues. The small Imperial pint aluminum water boiler was fired this weekend. Please refer to the Laboratory Evaluation for details of this unique water-heating device.

After an extensive walk about the estate (lawn mowed), the kettle was filled with cold water from the on-demand stream (backyard faucet). Seasoned and dry Western Red Cedar was procured from the carving bench to fuel the kettle.

My Granfors Brux Hunter’s Ax and Dozier Slim Outdoorsman were gathered and used to prepare small shavings, curls and a couple of fuzz sticks from the cedar.

The tinder was ignited with a strike anywhere match.

After the tinder set started, the kettle chimney was placed on the fire pan. Proper handling was utilized at all times, (watch the fingers ). Additional small cedar splits were dropped into the chimney and off it went.

Vigorous boiling was achieved in about 5-6 minutes. Additional cedar splits about 4-5 inches long were dropped down the chimney as needed. The kettle burned fast and hot using this fuel. These formed a sort of fire teepee as the splits were dropped in. The bottom seal again leaked but not as severely as the previous Laboratory Evaluation boils. A small amount of water was in the firepan, but because most of the burning wood was above the pan in the chimney this was not a problem. As the water got hotter, the leaking stopped.

Overall this is a fun and useful boiler. It is lightweight and has the ability to use found fuels ; which makes it a very useful daytrip brewup kettle, and useful in boil only longer trips. This most likely will not replace my MSR stoves or other devices for longer trips where more than boiled water would be desired, but it will make its way into those daytrips/fishing trips/picnics that would benefit from a hot beverage or instant soup etc at the lunch break. The larger Kelly Kettle would be necessary for parties larger than 1 or 2.

Kelly Kettle Chimney Interior....hum where does the water go ?

I boiled up with the Kettle again this weekend. I used some Alder that fell in a windstorm early last Fall. I split out wood from about a 2" round limb. This limb had been suspended above the ground but exposed to rain all winter. I stripped the bark and exposed the center wood, made splits and some curls with this. I attempted to ignite the kindling with my Swedish firesteel and a very small pile of Maya wood dust and splinters which I had placed in the Kettle firepan near the air holes. My first pull of the firesteel rocked the pan around completely disturbing my setup. So I added a vaseline cotton ball and started it this way. I had to tend the kindling sets much more than my cedar setup of last weekend, but once the fire pan set of curls was going I placed the chimney and dropped several splits in and off it went much like the previous burn.


Cotton Sparked


I fired it twice using the alder and did not notice much difference in the burn characteristics except flames did not jet out the top of the kettle. I did get quite a bit of wood residue in the kettle chimney this time and the leaking was nearly insignificant.

To start with Firesteel and either cedar nest or Maya wood dust would require a bit of flat wood or bark be set up with the spark catcher outside of the firepan then moved into the tinder set in the firepan. It was just too difficult to control the firepan, keep my spark set and tinder arranged while I tried to spark it. Doing this outside of the pan should work, but I did not try it. Of course, the cotton vaseline worked great.....but a bit of a cheat.

Because the Kelly Kettle functions like a small enclosed furnace, less than ideal fuels can be used in it with good result. Reasonable care should be taken to prepare a good tinder set using small splits, shavings, dry twigs etc, but once these are well alight and the chimney is drawing well, lower quality fuels can be added as needed. Very little preparation or attention is required compared to building a small fire on the ground as the chimney keeps a good draft going to assist the burn. I have burned twigs, dry grasses, small pine cones, bark and splits from downed but not seasoned wood. Most settings will provide handfuls of small dry twigs that can be used by simply shaving a few curls with a pocket knife. A large knife or ax would not be needed to use these small fuel sources.

Enjoyed my tea after aerating the lawn.

2007 Addendum

Well it has been quite a while since I edited this article, my first on the magazine, and some things have changed.....I have added a large Kelly Kettle to my gear box.

I actually purchased the 2.5 pint Kelly last year and simply put it in my car trunk kit. Both my wife and I volunteer with our local emergency response HAM radio communications group and our “Go Kit” has the essentials for us should we be deployed either in the field or at the Emergency Operations Center (EOC). One of those essentials is coffee...

The small one-pint Kelly is a wonderful device for short hikes, or brewups but more boiling water is needed for emergency workers. Normally the EOC’s operate on emergency power and getting that essential cup of coffee is relatively easy...not always the best cup of coffee but generally caffeine rich. Field deployment can range from search to sand bagging, and these exercises call for a good cup of joe as often as possible. So enter the large Kelly, which along with a filter cone and thermos can supply coffee for a long time on locally found fuels.

Recently I decided to do the “burn in” on the large Kelly to rid it of excess sealant etc. So, in keeping with my tradition of Kelly use, I decided to light it up using a firesteel and a new folding Ingram SodBuster.

The setup, both the large and small Kelly Kettles for scale, some birchbark, cedar bark, small kindling, firesteel, Imperial gunpowder tea, mug, and the new knife.

First a couple of fuzz sticks.

Then some cedar bark dust scrapings to catch the spark.

And a few cedar shaving to catch the flame

Cedar dust and shavings on a small piece of precious birch bark to catch the firesteel sparks. Note, I used the square edged kick of this folding SodBuster to strike the steel, not the edge or the spine of the knife.

Then blown up to flame

And transferred to the Kelly firepan

And the first boil....

Tea....really sort of gritty tea as this first boil and the next 3 needed to be discarded to clear the Kelly of its sealant.

This large Kelly is now ready for operations. I found it worked just as well as the small Kelly and did not have a single leak in evidence.

Overall I rate these devices as not only being very clever but as a very useful tool for an emergency kit. Last fall we had two major wind/rain storms and over 2 million homes in the area were without power for several days. My home was without power for 4.5 days but we had gas for our kitchen stove and did not need to use our campstoves or Kelly, but many people were not so lucky and found themselves living with others or in shelters.


Kelly Kettle site

Lee Valley, a good source for Kelly Kettles in the US and Canada

Post-Scriptum :

Original article published on Oldjimbo’s site.

28-07-2007 James, broken link fixed.

06/28/2007 Large Kelly added with comments and images

par Schwert,



Le 13 janvier 2004
Le 20 avril 2004

Sorry, but it is a lot simpler than all that. You really don’t need to use wood shavings - sticks and grass and bark lying work better even if wet. Also, it is best to light it with the kettle already on and the sticks and bark sticking up into the kettle. 1 match. Less than 5 minutes for full rolling boil. With practice using the small kettle you can stop and be on your way with a full Nalgene Bottle of Hot Chocolate in less than 5 minutes, having already drank a quick half litre. The small one holds under a litre, but by the time you mix it down to 60C = 158F, you have 1.5 litres.

While hiking I grab my fuel and stuff it up my kettle - a handful of birch bark and a handful of spruce sticks. I stop, fill the kettle with water from stream and light it. While it is heating, I mix my hot chocolate & skim milk powder with about 500ml of water and shake it up in my Nalgene Bottle. By the time I’m done that its boiling. I pour half a litre in shake it up and drink half, then I pour the rest of the boiling water in and I’m on my way. Even with 3 or 4 people, this thing cranks out boiling water faster than you know what to do with it.

It can leak a little at the bottom - you should never heat the kettle empty - but this is self correcting and doesn’t matter if the fuel is sticking up into the kettle. I’ve had mine for 3 years now use it for everything from dayhikes on up. 1.2 pounds isn’t much when you consider you don’t need fuel, or even a pot.

Le 31 août 2005
Sure it can be simpler, but if you have a Granfors Brux Hunter’s Ax and Dozier Slim Outdoorsman handy you’re sort of honor bound to play with them a little ! At least that’s how it works in my world.
R,S, Tudor
Le 30 septembre 2005

I bought one after watching "A Passion for Angling, X years ago. Now would not go out into the sticks without one. Even used it on M25 while on 2hour standing tail back, Between a drinks vending rep, a Truck Driver (Who had the water) & my kelly kettle, We & a number of others Passed the time in comfort, with a hot drink.

R,S, Tudor

Le 10 décembre 2005
I orderded one after seeing it on the web site Love it Made tea today while duck hunting I have the smaller one just right for two people I plan to use it while backpacking this summer
Le 1er juin 2006

Great product but :

Aluminium isnt good for us - Alzheimers. I thought that cooking pans in aluminium had been discontinued ?

Le 1er juin 2006

Hello, yes, excellent remark, but it is light.

Azlheimer, and osteoporosis may be related with alumium intake.

I personally avoid all cooking in aluminum containers, and use of aluminium wrappings.

This said, aluminium is still used a lot in outdoor gear, because of it’s weight. The alternatives for cooking are thin stainless steel or more expensive titanium.

At the end, still better an aluminium pot or quart or canteen than a teflon coated version of it. Teflon is known to be extremely carcinogenic and using it on cooking implements is just crazy. (email me for more references)

Le 16 avril 2007



Le 29 juin 2007
Large, 2.5 pint Kelly Kettle images and comments added to the article.
Le 10 juillet 2007

Actually, the link between aluminium intake and Alzheimer’s is very tenuous. A causal relationship has never been established. The layperson can read up on the issue at :

More scientific :

It boils down to the fact that aluminium intake from cookware is fairly insignificant when compared to intake from other sources (foods for example), especially when using hard-anodised Al pots and pans. Extremely acidic foods do leach some Al though.

The Teflon/PFOA-Cancer link is slightly more substantial, but even then can be debated when simply using cookware :

Le 12 juillet 2007
I seem to remember however that the link between aluminium intake and osteoporosis in women ?
Le 12 juillet 2007

Teflon : Well, I had an uncle working at a Tefal plant in their early stages, and they had to replace an abnormal number of workers with fried neurons (I mean brain tumors). Not something you’d claim on the roof for a food product either...

All tests are done with new pans and sets in perfect order, now, who has always a new pan which does not loose microscopic particles of teflon, because it has been over burned and scratched ??

UK Pike Angler
Le 19 décembre 2007

I’ve used one of these for a few weeks now and it beats all the various stoves I’ve used outdoors before hands-down.

All it takes to get it going is some paper and kindling. Get one of the cook sets and you can cook on it too and all for free when it comes to fuel.

Le 22 décembre 2007
I saw this being used at a recent Scouting event in Cambridgeshire.... soooo good ! my Christmas list has one on it !’s hoping
Le 8 janvier 2008
I think this is an excellent product. I have used it allot when off roading walking and camping.
Le 29 janvier 2008

I have been using a Kelly Kettle on most of my outdoor forays and fishing trips for many years, now. It’s possible I have the first one in North Carolina, which was obtained from England, as there were no known US dealers at the time. I saw one being used on a British fishing video.

I use anything burnable I can find where I’m at...the Kettle is certainly not fussy, just point the air hole into whatever prevailing breeze you have and light it. If it’s cold, warm your hands (carefully) over the chimney while you wait the short time for the water to boil.

I put instant coffee, creamer, sweetener, hot chocolate and instant soup in a gallon size baggie, along with a couple of plastic spoons and throwaway, burnable cups, and stow it all in the supplied cloth bag with the Kettle.

LOVE IT !!!!!!!!

Le 26 février 2008
Hi guy’s it’s a great thing, this Kelly Kettle. Now sold in the US you can find them at
Le 4 juin 2008
The original two skin kettle was designed by New Zealand soldiers in the Egyptian desert (WW II) where there was a crucial shortage of inflammable material. After the war it was commercially developed and marketed as a "Thermette". This was made of galvanised iron but much better versions are now available which are made of copper, which of course conducts the heat much more quickly and doesn’t corrode. These copper kettles are sold for around $US80 and are very popular.
Le 1er juillet 2008

Read up on new stainless steel sometime....seems like there is a lot of nickel and chromium that can contribute to metal sensitivities in some folks.........

seems like i read that if a magnet won’t stick than its not really stainless anymore ?

Le 27 juillet 2008

Great review !

I really want to buy one of these, but my wife just says, "take a flask". How do I circumvent her logic and get my hands on the prize ?