Reviews > Cook Gear > Stoves > Trail Designs Caldera Cone Stove System > Ralph Ditton > Test Report by Ralph Ditton

I have evolved from being a heavyweight backpacker of approximately 28 kg (62 lb) including all my water and food to a mid- weight backpacker averaging 18 kg (40 lb). I am still trying to get lighter with better equipment. My trips range from overnighters to five days duration.

Product Information
Manufacturer: Trail Designs.
Manufacturer's URL: http://www.traildesigns.com
Year of manufacture: 2006.
Made in: USA.
Colour of cone: anodised aluminium.
Listed weight of cone and stove: 57 g (2.1 oz.)
Model: 3 cup Caldera Cone System.
MSRP: US $35.

My Measurements
Weight of stove: 16 g (0.56 oz).
Weight of cone: 43 g (1.52 oz).
Total: 59 g (2.08 oz).
Outside diameter of stove: 66 mm (2.59 in).
Diameter of stove base: 82 mm (3.22 in).
Height of stove: 39 mm (1.5 in).
Diameter of stove burner head opening: 30 mm (1.18 in).
No. of air inlet holes on outside of stove: 12.
Diameter of outside air inlet holes: 6 mm (0.23 in).
No. of air inlet holes on inside of stove: 10.
Diameter of inside air inlet holes: 6 mm (0.23 in).
Cone dimensions, assembled: Diameter of base. 185 mm (7.28 in).
                                                      Diameter of top. 130 mm (5.11 in).
                                                      Height. 145 mm (5.7 in).

Expectations from the web site/Initial impressions
I had an open mind to alcohol stove cookery as I had never done it before with this type of fuel, so I had a good look at the web site and tried to understand the set up of the stove, pot and windshield.
The cone, with the top cut off, holds the pot by its top lip to prevent it from falling onto the stove. Another photo from the website shows examples of a series of cones in a row supporting pots with and without lids.
Judging by the description and the two photos on the website I had a fair understanding of what to expect upon receipt.
Upon arrival, the contents proved to be as expected but I was surprised by the method of how the cone windshield clipped together as I did not give it a thought and did not notice it on the web site. The other surprise was the notch at the top of the cone. It makes perfect sense because there needs to be an area where the pot can be gripped by a spondonical/pot lifter to lift off the heat and this could not be done if the top of the cone supported the pot by 360 degrees.

Product Description
The Trail Designs Caldera Cone Stove system is a two part unit which the manufacturer claims that the unit delivers the maximum heat to a pot for cooking purposes. The shield in the shape of a cone, encloses the stove and pot to maximise the heat output and shields the flame from the wind.
The stove is a top burner fuelled by methylated spirits which is a 96% ethanol solution.
As part of the package, an Antigravity Gear non-stick aluminium 3 cup pot with lid was supplied as this pot fits like a glove into the top of the cone with the top lip resting on the top edge of the cone.

pot inside cone

The stove is made out of two soft drink aluminium cans of a different diameter so that one fits inside the other leaving a cavity between the walls of about 6 mm (0.23 in).
The outside air inlet holes are 10 mm (0.39 in) from the base and the internal air inlet holes are about 3 mm (0.11 in) from the top.
The base of the stove has a diameter of 82 mm (3.22 in) giving it a stable platform.
Methylated spirits is poured into the top of the stove through the 30 mm (1.18 in) opening and then lit.

stove with integrated primer pan

The aluminium cone when laid out flat, measures from the bottom corner to the other bottom corner 555 mm (21.85 in).
There are nine air vents on the top of the cone, with five on the top row and four on the second row. Along the bottom edge there are four air vents. The air vents measure 25 mm (0.98 in) long x 6 mm (0.23 in) high.
On one end of the unrolled cone there are three tabs which fit into three slots on the opposite end when bent into a cone shape. The tabs must be inserted into their slots from the outside  towards the inside.
To help lock the tabs into position, there are two vertical ribs. When the shield is bent into the conical shape, the two vertical ribs mate together, one inside the other.

unrolled cone
The height of the vertical ribs is 114 mm (4.48 in) leaving a notch at the top of the cone measuring  28 mm (1.1 in) high x 37 mm (1.45 in) wide.
This is the area where the spondonical is used to lift the pot off the flame and out of the cone.

interlocking ribs and notch

Test Plan

• The pot is supported very well by the cone.
• The cone is very easy to clip together and unclip.
• Very lightweight.

Field test
The testing location that I used for three overnighters is the Prickly Bark campsite on the Coastal Plain Trail. This campsite sits at an elevation of 83m (272 ft) amongst Banksia trees on top of a large sand dune that has shrubs, grass and wildflowers. On the first occasion that I used the stove, the evening temperature was about 20 C (68 F) and the wind was WNW at 11 knots.
The fuel used on every occasion is methylated spirits.
The evening meal that I warmed up was a thawed left over meal of stir fry beef in a sauce with rice. I poured 30 ml (1 oz) of fuel into the stove and lit it. The meat, sauce and rice was put into the Antigravity Gear non-stick aluminium 3 cup pot. I had to stir the meal while it was heating up to try and prevent it sticking to the bottom. I was not totally successful as the meal did stick in spots on the bottom of the pot.
Unfortunately, I neglected to time the cooking process, but I estimate it  took about 10 minutes to heat the meal through. I judged the warmth of the meal by sticking the tip of my finger into the food from time to time to ascertain how it was coming along.
When I was happy that the meal was warmed up, I took the pot out of the cone, and used the pot's lid to cover the flame to extinguish it. After the stove cooled down I tipped the remaining fuel out into a measuring cup to see how much fuel was left. After some spillage I had 5 ml (0.17 oz) left. (Comment. When I tried to pour the balance of the fuel into the measuring cup, some of the fuel found exits through the holes on the side of the stove and spilled out over my arm and onto the table.)
The stove cooled down very quickly, within a matter of minutes.

For breakfast I poached two eggs. The temperature was at 19 C (66 F) with the wind coming from the west at 7 knots.
I measured out 1½ cups of water and put it into the pot and then measured out 20 ml (0.67 oz) of fuel and put that in the stove. This time I used the stop watch function on my mobile phone to time the cooking process. It took 4 minutes 26 seconds to bring the water to a rolling boil with the lid on. I then added salt to the water and then cracked the eggs and added  them to the water, one at a time, then replaced the lid. The eggs cooked within three minutes. I like them hard.

During the cooking of the eggs I noticed a burnishing on the cone at the top junction of the matching ribs. I suspect that I did not have the stove centrally placed under the pot as I could see flames coming up through the top notch where the spondonical/ pot lifter is used. I moved the pot and cone unit to try and have the stove centrally under the pot when I was cooking the eggs.

burnishing

The next occasion at the same location I cooked an evening meal of two lamb chops and five chipolata sausages using a small fry pan that sat on top of the cone. The fry pan base diameter measured 160 mm (6.29 in), height 35 mm (1.37 in) and top diameter of 200 mm (7.87 in).
The handle was removed.
Prior to placing the fry pan on top of the cone, I had the cone in place covering the stove and stove was fuelled up with 25 ml (0.85 oz) when the wind blew the cone along the table. The stove was dragged along with it. The conditions at 5.30 pm were as follows: (Source. Bureau of Meteorology).
Temperature: 19 C (66 F).
Relative Humidity: 64%.
Wind: Easterly.
Wind speed: 16 knots.
Raining: Yes.
 I moved the stove and cone into a more sheltered part of the hut so that the cone did not act as a sail. I then commenced to cook my meal.
It took one refill of fuel measuring another 25 ml (0.85 oz) making the total to cook the meal 50 ml (1.7 oz). I only had to wait about 30 seconds before the stove was cool enough to refill. I estimate that it took around 30 minutes to cook the meal.
The base of the fry pan has a layer of black soot from the flames. It came off very easily just by wiping it with a damp tissue.
For breakfast I just used the pot in the cone to boil water for my morning cup of tea.
I used about 10 ml (0.33 oz) and it took about three and a half minutes to bring the cup of water to the boil. There was a little bit left but I spilled it all trying to get it out to measure. The temperature was 24 C (75 F) with the wind still blowing from the east at 15 knots.

On the third occasion at Prickly Bark I cooked an evening meal of Oyster Blade steak with fried eggs using the same fry pan as above.
The temperature was 20 C (68 F) with the wind WSW at 13 knots.
The cooking process took 31 minutes with one measure of 30 ml (1 oz) and a refill of 30 ml (1 oz) making a total of 60 ml (2 oz). It takes fifteen minutes to burn 30 ml (1 oz) of fuel. I like my meat medium to well done.

oyster blade in fry pan
Again the base of the fry pan had a layer of black soot.

oyster blade and eggs

For breakfast I treated myself to another two poached eggs. The weather conditions were 15 C (59 F) with the wind coming from the south at 3 knots.
This time I put 25 ml (0.85 oz) of fuel into the stove and waited till the water was just warm before putting the salt and eggs into the water. It took only seven minutes to cook the eggs hard. I estimated that I had between 10 - 12 ml (0.33 - 0.4 oz) of fuel left.


poached eggs

The crown of the cone has a nice coppery burnishing on the outside from the flames through the cooking processes.

burnishing
Findings to date
The flame from the stove reaches to the top of the cone and heats the base of my little fry pan extremely well. Enough heat is generated to cook meat and fry eggs. I do not mind spending up to half an hour cooking my meat to a medium to well done state. This is a very similar time span to my own Bar-B-Q at home when cooking a thick rump or T bone. I am not keen on the rare state of cooked meat.
During the cooking process I estimated that a rare piece of meat would take about six minutes. That is, cooked on both sides to within 2 mm (0.07 in) and raw thereafter.
I have not had to use the primer pan due to the current summer temperatures that we are experiencing, however, I will endeavour to give it a try and comment on how effective it is in the Long Term Report.
There is no ability to simmer with a simmer ring as I would have to make one up and lifting the pot and cone off the stove during the cooking process is a fiddly process. I found that it is best to leave all pieces of the cooking set-up in place. I believe in minimum disruption to the cooking process as I have experienced spilled meals before on other stoves when trying to move things around.
To date, the Caldera Cone stove is a very good ultra light alternative to a canister gas stove. Admittedly, I have used both on two of the occasions as I had a friend with me. When I was cooking the poached eggs, he was cooking bacon and tomato  on the gas stove so that all food products were ready at the same time.
When I was by my self I just used the Caldera Cone stove.
I have found no trade offs by using the alcohol stove as opposed to my gas stove. Cooking time of meat is about the same but the alcohol stove boils water much faster. It takes me about eleven minutes with a gas stove on a moderate flame and only around four and a half minutes with the Caldera Cone stove for the same volume of water.
There are no moving parts to this stove set up apart from the wind blowing the cone along the table, so there has been no maintenance problems at all. There is no sign of rust on the stove or cone after being subject to flame.
I found that the stove cools down extremely quickly when it either runs out of fuel or I dampen the flame after the cooking is done. I can refuel the stove within a minute and a half to continue cooking my meat without any danger of self ignition of the fuel.
The Caldera Cone stove is definitely not a one person stove system that just boils water or rehydrate food in water. The top of the cone can become a cooking ring to support a small pan or bowl.

To date, I am very impressed with the set-up and it will become a standard piece of equipment in my backpack.
Thank you Trail Designs for giving us the opportunity to test this unit.

This concludes my Field Report. The Long Term Report should be completed in approximately two months from the date of this report. Please check back then for further information.

extremely quickly and I can handle it with my bare hands/fingers within half a minute  of the flame finishing.

On both occasions for breakfast I cooked bacon, eggs and tomato in the pan that sat on top of the cone. The cook times were always the same time as was the fuel consumption. As I like my bacon with crispy rind and I was cooking for two it took around twenty five minutes as I was juggling the bacon and tomatoes for space in the small pan. The eggs went in last  as the bacon shrinks during the cooking process making room for the fried eggs and my friend and I like our eggs with soft yokes. I used about 60 ml (2 fl oz) of fuel.
When my mate was serving up the breakfast on both mornings, I then used the supplied pot with the stove to boil water for a cup of tea to wash breakfast down. For this exercise I used 10 ml (0.33 fl oz) of fuel and the water came to a rolling boil within 4 and a half minutes. There was fuel left in the stove but I let it burn out.
The pan used in this stage of the trial is the same one used in the Field Report. It has a base diameter of 160 mm (6.29 in), height of 35 mm (1.37 in) and a top diameter of 200 mm (7.87 in).

The next evening meal that I cooked was of sausages as I had four people to cook for and I had to do it in two stages. My friend had his young 10 year old daughter and her friend with us, so I cooked their sausages first. The six normal length butcher sausages just fit inside the pan but they did shrink during the cooking process. It took around 20 minutes to cook the sausages and I used around 45 ml (1.5 fl oz) of fuel. I measured out 30 ml (1 fl oz) of fuel and burnt this first then when it ran out I put in another 15 ml (0.5 fl oz) to complete the cooking.
When the girls were given their meal of sausages and salad I started to cook the sausages for my friend and myself using the same amount of fuel. It took around a similar time to complete the cooking process.
That night the girls were badgering us to cook marshmallows in the fire ring. I told them that due to the fire ban we could not do it. I then came up with a solution, why not use the flame from the alcohol stove with the cone as it was a bit windy.
The girls were very happy to use the flame from the Caldera Cone Stove to cook their marshmallows.
I put 30 ml (1 fl oz) of fuel into the stove and that gave the girls 15 minutes of burn time to cook and eat as many marshmallows as their tummies could handle. They managed to get through the packet. It was a big success.

cooking marshmallows

The two marshmallow cooks

For my next trial I cooked one Chicken Schnitzel in  my pan at a time using various heights of the stove. For the first Chicken Schnitzel I raised the stove 30 mm (0.03 in) from the base level of the bottom of the cone. I did this by putting a piece of wood under the stove. I placed 45 ml (1.5 fl oz) of fuel into the stove and I cooked the Chicken Schnitzel. The cooking process took around 26 minutes. I then removed the block of wood and then proceeded to cook the second Chicken Schnitzel. About 8 minutes later the fuel from the initial process ran out, so I refilled the stove with 50 ml (1.7 fl oz) of fuel to complete the cooking of the second Chicken Schnitzel.  I addeded the extra fuel because the stove was further away and I thought it might use more fuel to cook. This Chicken Schnitzel only took 28 minutes to cook and I ended up with surplus fuel in the stove. I just let it burn away but I estimate that I had around 20 ml (0.7 in) left.
The conclusion that I came to was that it did not matter at what height the stove was to the base of the pot or fry pan. The flame from the fuel cooked the food in a timely manner. One thing was consistent. The fuel burned at a regular rate irrespective of the outside temperature and wind speed. The rate of burn came out at 15 minutes per 30 ml (1 fl oz). I just had to calculate how long approximately an item of food would take to cook and add the appropriate amount of fuel to the stove.

On two occasions the supplied fuel bottle did leak. When it first happened I noticed that the fuel came out through the cap and a little seeped into the plastic cup supplied by the manufacturer as I had the fuel bottle inside it. Whenever I took it in my backpack I still placed it inside the provided cup but I also added an extra level of precaution by placing the fuel bottle inside a clip lock plastic bag.
The second time the fuel bottle leaked it was inside the clip lock plastic bag. When I opened my backpack, the cup with the contents had shifted and was laying on its side. As a test when I held the fuel bottle upside down at home full of fuel it did not leak. I suspect the extreme heat of the day may have caused the fuel to leak into the clip lock bag. The outside temperature was 41 C (106 F) when I was carrying it in my backpack during the morning and it dived down to 39 C (102 F) when I took it from my backpack to use at lunchtime. This is when I noticed some spillage inside the clip lock bag. I estimate that the amount of fuel caught by the clip lock bag to be around 15 ml (0.5 fl oz) which suggest a slow leakage over the six and a half hours from when I started to when I took it out of my backpack. I would recommend that the manufacturer does away with the cap that incorporates a spout and have a normal solid cap.

Things I like

• The pot and fry pan are well supported by the metal cone.
• The cone is very easy to assemble and disassemble.
• It is extremely lightweight.
• Boils water much quicker than a gas stove.
• The flame reaches well above the top of the cone so there is no need to jack up the stove.

• Leaking fuel bottle which I suspect is through the spout housing cap.

Reviews > Cook Gear > Stoves > Trail Designs Caldera Cone Stove System > Ralph Ditton > Test Report by Ralph Ditton