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Reviews > Cook Gear > Stoves > Trail Designs Gram Cracker > Test Report by Jamie Lawrence
Trail Designs Gram Cracker
Test Series by Jamie Lawrence
I was introduced to backpacking/tramping/hiking as a young child in Boy Scouts and through my school physical/adventure education. After leaving school, I mainly did short daywalks until recently when I started to re-walk some of Tasmania's key routes and try others I have yet to attempt. I mainly walk in the winter months, in Tasmania's central highlands area. I prefer light gear, extended walks (3-5 days) in a group of 3 people, or shorter walks (1-3 days) walking solo. I generally carry a base weight pack of around 8 kg - 10 kg (17 lbs - 22 lbs).
14th March 2011
Product Information & Specification
The Trail Designs Gram Cracker is a solid fuel burning stove designed to be used primarily with the Caldera Cone system. The kit consists of essentially a small sheet of aluminium used as a protective heat shield which a small titanium cradle rests on. This cradle perfectly holds an Esbit tablet. There are also 2 titanium wings that clip into the cradle that can be used to control the burn rate of the Esbit tablet and also help stablise the tablets if 2 are stacked on top of each other to facilitate a longer burn time.
The kit I received came with a small instruction sheet, 3 Esbit tablets and a zip-lock waterproof bag for storing the kit plus a lighter/matches.
I must admit, my first impressions of the Gram Cracker where along the lines of 'is that it??!!' as I was at first shocked at how little this piece of gear actually is. Given I am more than happy to admit that I love my complicated white spirit burning stove, as I love the pyro-technic show and noise associated with using it. By comparison I felt a bit cheated by the simplicity of the Gram Cracker, as it is simply a few bits of metal cut to size. Well, that was my first thought.
I have never previously used solid fuel to cook when outdoors. My fist stove was an alcohol burning Trangia. As I ventured into the back country and above the snowline, I embraced my MSR Whisperlight with much passion. I have recently started using canister stoves when the weather 'suits' or I simply forgot to buy some more fuel for the MSR.
Trail Designs have clearly designed this solid fuel burning option for those lightweighters who are seriously wanting to shed even more weight from their already tissue weight Caldera Cone system. The Gram Cracker replaces the 12-10 alcohol burner or wood fuel as the heat source for the Caldera Cone. This can be seen in the images above, where I have set the Gram Cracker in the middle of my Caldera Cone ready to cook.
Instructions, set-up and use
The included instructions for the Gram Cracker are, as you would expect, pretty simple. 3 steps and you're away! Place the cradle on top of the foil sheet, sit an Esbit tablet on top of the cradle, then add a wing or 2, depending on how long you would like the table to burn. The only set up that is required is to insert the small titanium wings into the slots on the side of the cradle. Although handy for stablising the tablet, the instructions clearly outline that the 3 different options for the wings (none, 1 inserted or both inserted) are to control the burn rate of the tablet. No wings achieves the fasted burn time whilst both has the greatest efficiency of burn. For my first use of the Gram Cracker I inserted both wings with 1 Esbit tablet.
For my first test, I decided to see how long it would take to boil 500 ml (17 fl oz) of water and then how long the Esbit tablet would burn for with 2 wings attached to the cradle. I conducted this simple test on the back step of my house, on a warm sunny day with no wind. The temp was a really nice 24 C (75 F) and the water was out of the garden tap. I did not take a temperature reading but it was cool water, not overly cold.
I set up the Gram Cracker in the middle of my Caldera Cone and then lit the tablet. It took about 10-15 seconds before it was obvious that the tablet was lit. See above photos. I then sat the pot in the cone and started waiting. The pot boiled in around 9 minutes. Nothing obvious seemed to happen for the first 6 minutes apart from the odd crackle of the burning tablet. However the whole Caldera Cone became obviously hot and I could feel the heat radiating from the vents. After the water had boiled, I then emptied the pot, dunked it in a bucket of cold water to cool the pot then added another 250 ml (8.5 fl oz) of water. I did not add another 500 ml (17 fl oz) as I noticed the tablet had clearly burned away a lot and I doubted it had enough burn time to boil a full 500 ml. I decided to halve the volume and see how close it came. The above image shows the half burnt tablet once the first pot of water had boiled.
The remaining tablet was not enough to boil the water. It did start to form bubbles so I estimate it got to around 60-70 C (140-160 F). In total the tablet burned for 15 minutes 43 seconds.
There were 2 noticeable 'residues' after I had burnt the Esbit tablet. The first was some black tarnishing of the base of my pot. Not expected but not surprising either. The second was a glue like gum left in the cradle, which made the wings 'stick' into the cradle. The images below show the base of the pot and the residue left on one of the wings after I removed it from the cradle. I was not able to wash off the blackening from the base of my pot. I was able to chip away most of the gum and the wing inserted freely into the side of the cradle without hassle, so it appears there was no lasting impact. As I have never used an Esbit tablet before, I did not expect this residue but after a quick read on the Internet, found it does happen.
My first impressions of the Trail Designs Gram Cracker are good. Sure, it isn't anywhere near as fast at boiling water as my other stoves, but it is stupidly lightweight, has no moving parts and simple to use so that's a good trade-off in my books. Whilst I think the Gram Cracker may be just on the border between a primary cook system (when used withe Caldera Cone) and emergency heat source, it was certainly effective in my initial test.
The obvious trade-off with using the Gram Cracker appears to be the lightweight of the system vs the complete lack of control, eg light and just let it burn. I will be interested to test how the use of no or 1 wing impacts the burn times or perhaps the use of multiple Esbit tablets, when compared to my initial test. I look forward to testing this unique product in the field and working out if I am able to do more than simply boil water when using the Gram Cracker with my Caldera Cone.
This concludes my Initial Report of the Trail Designs Gram Cracker. Please check back in June for the results of my field testing. My thanks to Trail Designs and www.backpackgeartest.org for the opportunity to test this product.
13th June 2011
Field Locations and Conditions
I have used the Gram Cracker Stove on 2 separate outings to date. The first of these was a 5 day back country trip based from the Labyrinth, deep in the Tasmanian central highlands. The second trip was an extended day walk to the Tarn Shelf in the Mt Field national park, round 80 km (50 mi) from my home in Hobart.
The Labyrinth - This walk was intended to be a back country outing to a remote alpine lake for us to enjoy some rare photography opportunities. Alas! We experienced all sorts of weather ranging from pouring rain (and snow) and gale forced winds to perfect sunshine and breathtaking sunsets. Over the 5 days our elevation ranged from around 700 m (2,296 ft) to around 1,300 m (4,265 ft) and weather ranged from below freezing to sunny clear skys of around 15 C (59 F). As mentioned we had a couple of days of pouring rain, hail and snow but I am not sure how much fell. The closest weather station was at Lake St Clair, around 20 km (12 mi) away and they recorded around 250 mm (9.8 in) in one 24 hour period, which gives an idea of just how wet it was! All our camping was tent based in exposed sites, except for 1 night where we camped near a walkers hut in a pine forest.
Tarn Shelf - This walk was a day walk of about 6 hours in the M Field National Park, my favourite park close to home. The walk starts at a lake at 1,034 m (3,392 ft) and climbs steeply onto an exposed alpine tarn at 1,160 m (3,805 ft) where there are lovely lakes and tarns and is a very popular day walking destination. Unfortunately for me, the weather was absolutely foul and after about 2.5 hours of being blasted by icy winds and more hail and rain, we turned around having seen very little. There is a large cabin on the track which made for a good spot to stop, warm up with a bite to eat and a hot drink.
Performance in the Field
I have been testing the Gram Cracker in conjunction with the Caldera Cone & 12-10 Stove, with my reporting found here. This report is focused simply on the performance of the Gram Cracker.
The Gram Cracker, along with the complete Caldera Cone system, was carried with me on the 2 above trips. However I used the Gram Cracker as a 'second' stove rather than as a primary cooking source for 2 main reasons. Firstly, the pot with my Caldera Cone is simply too small for group cooking and as I was traveling in a group of 4, I wasn't interested in cooking specifically for me just to use the stove. The second is I only carried about 8 fuel tablets with me, not enough to rely on as a primary fuel supply for my 5 day trip. I view the Gram Cracker as a good emergency or back up option when I would rather not use the 12-10 stove with the Caldera Cone. As chance would have it, I actually found having both stoves handy.
The first issue I have had using the Gram Cracker is sourcing Esbit fuel. When I received the Gram Cracker, it included 3 Esbit tablets, which are quite large and rectangular. Despite looking in 4 outdoor retail stores and online, I have not been able to find the same solid fuel tablets for sale in Australia. I was able to buy a box of 24 small round hexamine fuel tablets for only a few dollars. Despite being smaller than the supplied Esbit tablets, I believe they are essentially the same fuel and should burn the same way.
During my trip in the Labyrinth, I would burn 2 of the solid fuel tablets that I had bought prior to the trip each time I used the Gram Cracker. I used the Gram Cracker only inside the vestibule of my tent, as at the time it was pouring with rain and I did not want to get outside to simply boil some water to rehydrate dinner. I had set my tent up on unstable and uneven alpine grass and scrub so I was not easily able to find a flat surface to cook on. However as the Gram Cracker is so light, I figured it could easily sit on the ground with minimal risk of tipping over and igniting the grass. It was also completely saturated from the few days of solid rain which helped!
Each time I used the Gram Cracker, it was easily able to boil the pot of water with sufficient burn time remaining to see the fuel tablets continue to burn for around 2-3 minutes after I had removed the pot. I did not try to use only 1 tablet to save fuel but I suspect that based on the amount of fuel left once the water had boiled, there would not be enough heat in 1 tablet alone to boil a pot of water.
I tried to test the configurations of the different panels to see if this increased or decreased burn time as suggested. I could not clearly see a difference in using 2 side panels or no panels as the burn time did not seem too much different (I wasn't able to time exactly) however because the round fuel tablets are much smaller than the rectangle tablets, I used 2 panels as I felt this was more stable and offered the greatest protection from the tablets tipping off the stove when in use due to the ground I was cooking on.
The Gram Cracker really is as simple as it gets. With no moving parts and fuel that will ignite when wet (which I tested by using in the rain!) it really is simply a case of placing the protective sheet down, pop a few tablets on and light... Plus, the whole set up is so light and fits into the smallest space. All this I like.
Unfortunately there are a few bits I don't like. Firstly, and mainly, when I was using the Gram Cracker in my tent, there was a lot of smoke when the fuel tablets were initially lit, which had a distinct chemical smell and lasted for around 30 seconds once I lit the tablets. Given I was in a confined space (I understood the risk and avoid cooking in my tent on all but the most extreme occasions) I was not overly comfortable inhaling this smoke and was forced to open the vestibule, letting in both cold air and rain. As experienced during my initial testing, I had a lot of residue left on my pot and the cone after burning the solid fuel. It was a bit sticky and annoying. I found it was easily removed with a wash in warm water but in my case, I would have had to burn more fuel to heat more water so not ideal. The other minor annoyance is my inability to purchase the rectangular Esbit tablets in Australia. There is no doubt that this stove is designed to work specifically with that fuel and therefore the fuel I am using is not 'ideal'.
Having said this, I do quite like the Gram Cracker stove. As it is so small and lightweight, I have no hesitations in packing it in my gear as an alternative stove. As I had to carry a small pot that is designed for the Caldera Cone, I simply store the Gram Cracker in the zip lock bag supplied with a few tablets inside the pot so it takes up no additional space in my pack. This was the case when I was walking in Mt Field and an additional bonus as I was only using a small 22 L (4.8 gallon) day pack.
So far I have found the Gram Cracker is good for what it is designed for, being a simple lightweight and easy to use solid fuel alternative for the Caldera Cone. I have not bothered to do anything more than simply use the Gram Cracker to boil water as I believe this is really all it is able to do. However, it does do this well, without too much fuss and when I tested it, in some horrible weather when burning wood simply wouldn't have been an option. Given the issues I have experienced with smoke and residue, I still think I will continue to regard the Gram Cracker as the alternative heat source for the Caldera Cone or when the weather simply makes the Gram Cracker a more user friendly option.
This concludes my Field Report of the Trail Designs Gram Cracker Stove. I will continue my testing and will report on my results in my Long-Term Report in the coming weeks. Again my thanks to Trail Designs and www.backpackgeartest.org for the opportunity to test this product.
6th August 2011
Field Locations & Conditions
My final phase testing of the Gram Cracker stove did not go as planned with 2 trips cancelled due to extremely poor weather. I did however manage to squeeze in a quick cross-country ski trip to Mt Field, in which I packed the stove to allow me to prepare a hot lunch or drink whist out carving up the slopes. After 2 weeks of beautiful cool weather and blue skies I was blessed with warming weather, melting snow and pouring rain later in the afternoon, cutting the trip short. When we set out the temp was around 3 C (37 F) but by the time I had returned to the car, it was closer to 7 C (44 F) and I had spent around an hour walking off the mountain in strong winds and rain. I am not sure how windy it was or how much rain fell, but it wasn't nice!
Performance in the Field
Taking the Gram Cracker above the snowline was as successful as I thought. I wanted to melt a small amount of snow to make a hot drink. I used 2 fuel tablets expecting this would be enough to melt the snow and boil the resulting water. As outlined in my Field Report, the use of the different wing configurations has done little for me, rather acting for stability more than burn time control. However the instructions clearly state that the maximum heat output is achieved by using no wings. This was the configuration I went for as I wanted the maximum heat output in order to melt the snow as quickly as possible.
I packed some snow into the pot, placed it inside the Caldera Cone then set up the Gram Cracker with 2 tablets. Once lit, I placed the cone/pot over the stove and sat back waiting. The result was slightly disappointing, but not unexpected. I found that about half way through the burning of the 2 tablets, the heat output started to drop away and this was enough to continue melting the snow but was never going to be enough to boil the water. I had 6 tablets with me, so the 4 remaining were more than enough to finish the job. It was about halfway through the burning of the second set of tablets that all the snow melted and boiled the water. All up this took well in excess of 20 minutes.
To be fair to the Gram Cracker, I am sure that Trail Designs did not design this stove for the purpose of melting snow and I have really taken this product to the limit in this regard. Despite this, it is pleasing to note that should I absolutely need it to, the Gram Cracker will work in these conditions.
During the total test period I have burnt around 13-15 fuel tablets with the Gram Cracker, including the 3 supplied. As previously highlighted, I have had difficulty purchasing tablets that are the same as the 3 Esbit tablets supplied with the Gram Cracker. This continues to be the case as none of my local retailers have been able to find stocks with their suppliers. Whilst this is a little annoying, it isn't my biggest annoyance with the fuel. I have 2 concerns with solid fuel tablets. Firstly the residue left from burning the tablets is simply annoying. This is by no means a clean burning fuel as the gummy residue has to be scraped off the Gram Cracker after use. Secondly, and more important from my perspective, is the fuel appears to have damaged the bottom of the pot.
As can be seen in the pictures above, the bottom of the pot I have been using with the Caldera Cone & Gram Cracker is quite worn, scratched and discoloured. Of particular concern is the middle of the pot which has gone very black and also has developed some orange marks that I can't scrub off. I noticed these after my snow melting experiment and assumed that I had simply managed to have some gunk stick onto the pot off the bench in the hut where I was testing. I used the Gram Cracker stove after I had been using the 12-10 alcohol stove that is also available for this Caldera Cone and I can't recall seeing the marks during my use of the alcohol burner. Damage to the pot wouldn't worry me too much but it is of greater concern with the Caldera Cone system as each cone perfectly fits the pot, so if I wear out this pot before the Cone, I need to purchase a replacement pot. Given what I would consider minimal use of the pot (by comparison to other pots I have had for many years) I was concerned about the effect this fuel was having on the pot base.
The Final Summary
Throughout my testing of the Gram Cracker I have tried hard not to think of the Gram Cracker as more than an super lightweight minimalist piece of gear, but as a genuine alternative to other fuel burning stoves. In my Initial Report I commented that I felt the Gram Cracker was on a border between being a primary cooking system and an emergency heat source. I am now firmly in the field that my continued use of the Gram Cracker would be the latter, based simply on the fact that with a few tablets and the Gram Cracker, I carry a few extra grams but know I have a heat source that I can use to boil some water if needed. I would not want to rely on the Gram Cracker solely as the fuel is expensive (in my view relative to alcohol which I can also burn in the Caldera Cone), burns produce an annoying residue and appear to damage the pot.
My above views may appear to be critical, but they are intended to express where I see the Gram Crackers place in my gear list. I do a lot of my bush walking in extremely sensitive national park environments, usually in the sub alpine and alpine regions. I always carry a flint lighter for emergency use but I would prefer to eat cold food to lighting a fire in these environments as even a small fire can do lasting damage to the ground and burnable fuel is very hard to find at times. However, I know I can carry the Gram Cracker in my pack with a couple of tablets and have a heat source. Ideally I would also need to carry the Caldera Cone but I could also simply hold a pot above the burning tablets to get similar results, which if it was an emergency, I am sure I would be happy to do if it meant having hot water. For me, this is the true advantage of the Gram Cracker, it is an alternative fuel option for the Caldera Cone (not preferred but alternative all the same) but also it is just so light and fail proof that it is a genuine advantage to carry it in my pack for those 'just in case' moments.
This concludes my testing of the Trail Designs Gram Cracker stove. Many final thanks to Trail Designs and http://www.backpackgeartest.org/ for the opportunity to test this product.
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