I picked up a Bear Grylls branded "Outdoor Cooking System" kit on clearance, and thought I'd try it out. I've seen a lot of conflicting information about the Zip military fuel, so I thought I'd be extra careful with how I did it. Specifically, I've seen some people say it works great and burns clean for a long time, and other says it burns really hot, fast, and sooty. (See, for example, this thread: http://www.bushcraftuk.com/forum/showthread.php?t=112211) I decided to take care to follow the instructions on the kit as closely as possible and see what happens, and compared to another solid fuel system, also used as instructed (and yet another test just for fun).
I compared the Zip setup to 14g Esbit in a Bleuet 3-piece kit, and also to a 7g Coghlans tablet also in the Bleuet.
Method
Most of my equipment for this test: Boilex pyramid, Zip fuel cubes, Bleuet system, hexamine tablets, etc
Test 1: 25g Zip Military Fuel cube and the Boilex Pyramid stove.
I put 250ml of cool water into the Bleuet 500ml pot, inserted a temperature probe and placed the lid onto the pot. I filled a shallow pan with garden soil, as the instructions on the Boilex say specifically to seat it into the soil. I placed the Zip fuel block onto the soil and lit it with a match. I then seated the Boilex stand around the block and waited 30 seconds to place the pot on top. I recorded the temperature of the water throughout the burn time.
Test 2: 14g Esbit hexamine tablet in Bleuet 3-piece set
As in Test 1, I used 250ml of cool water in the Bleuet pot with a temperature probe and lid. I placed this over the Bleuet cooker with the sliding door in the "open" position. I lit the cube with a lighter, and recorded the temperature throughout the burn time.
Test 3: 7g Coghlans hexamine tablet in Bleuet 3-piece set
Exactly as Test 2, except with the Coghlans tablet.
Results
These were the final results of the boil test:
The Zip+Boilex setup reached a boil in 13m05s and continued boiling for a further ~25m.
The Esbit+Bleuet setup reached a boil in 7m40s and continued boiling for a further ~10m.
The Coghlans+Bleuet setup did not boil, but it did heat water for nearly 10m.
Observations
Boiling:
The Zip+Boilex was significantly slower to boil than the Esbit+Bleuet. However, the fuel block maintained a steady heat output for more than 35 minutes. This is more than twice as long as the Esbit tab, which burned for approximately 15 minutes. The Coghlans tab did not bring the water to a boil. However, it maintained nearly the same heating rate as the Esbit tab while it was burning. If a second Coghlans tablet were added to the cooker at ~10 minutes, the heating would continue on for nearly 20 minutes, which is a slightly longer time than the single Esbit lasted. Perhaps the Esbit could burn for 20 minutes as well, if it were split in half and burned in two additions.
Burning characteristics:
The Zip+Boilex system left a small (almost negligible) amount of soot on the bottom of the pot. This was easily wiped away with a damp cloth. I noticed that the Zip system burned with a barely visible blue flame throughout most of its burn time. Once when I lifted the pot momentarily to verify that it was still burning, the flame flared up yellow, and produced some smoke. As soon as the pot was replaced on the stand the yellow flame died down. When the fuel burned out, it left a grey ashy hollow shell behind.
It was very clear to me that the Boilex pyramid was heavily influencing the burn in other ways, too. For example, the side of the fuel closest to the match/lighting hole near the base of the pyramid produced a small yellow flame (about 1 cm tall) throughout the burn. At the level of the upper holes, I could see a diffuse blue flame throughout the chamber. The restriction of oxygen clearly throttles the burn.
The Esbit tablet left a shiny deposit on the bottom of the pot and a small amount of blackening. This was removed mostly with a damp cloth, though it required somewhat more scrubbing. The tablet burned consistently and left very little residue.
The Coghlans tablet also left a small shiny deposit on the pot, and also required some scrubbing. There was a small puck of leftover material in the cooker.
Overall thoughts and conclusions
It seems that the Zip fuel depends on air control by the chamber in order to perform well. When it was contained within the pyramid and under the pot, it burned slowly and relatively cleanly. As soon as I lifted up the pot on top, a sooty yellow flame appeared. When used as directed under controlled conditions, the Zip+Boilex is a very good performer. This is especially true if you want a longer, controlled cook time. For example, I could see this combination being excellent for cooking food directly on top of the heat source, rather than simply for boiling water at maximum rate.
I do worry that it may be sensitive to wind. However, this is also true of hexamine, so it's not clear that Zip fuel suffers moreso.
I have seen on Zip's marketing materials that they claim it is faster than hexamine. In their own test: [video=youtube;HZV5Xl6erFg]https://www.youtube.com/watch?v=HZV5Xl6erFg[/video]
they seem to boil much faster than I did. Perhaps this is because they're using sand/steel under the fuel. In my test, I used damp soil which may seal the lower edges better to restrict the air more, and which may directly keep the fuel block cooler.
Overall, I found the Zip system to have a few advantages over the Esbit+Bleuet. First, the fuel lacks the fishy pong we all know and love
. Second, in controlled circumstances it burns for a long time at a decent heat that may be very useful for proper cooking besides boiling. Third, when controlled, it cleans up easier than hexamine.
It also has one big disadvantage, however. The Zip system appears to be very sensitive to the cooker it is used within. As described in David Morningstar's post linked above, when burned in a Crusader cooker, it burns hot and sooty. Clearly one cannot simply replace hexamine with Zip straight across and expect nothing but positives. Hexamine, on the other hand, seems to be a lot more cooker-indifferent (but maybe not? Hmmm....)
Would I switch over to the Zip system? I don't know, but even if it were more readily available to me, I doubt it. Hexamine is just too cheap and ubiquitous to abandon. But if I could find it, I can easily imagine that I'd pick up a few boxes to use when conditions suit it.
I compared the Zip setup to 14g Esbit in a Bleuet 3-piece kit, and also to a 7g Coghlans tablet also in the Bleuet.
Method
Most of my equipment for this test: Boilex pyramid, Zip fuel cubes, Bleuet system, hexamine tablets, etc
Test 1: 25g Zip Military Fuel cube and the Boilex Pyramid stove.
I put 250ml of cool water into the Bleuet 500ml pot, inserted a temperature probe and placed the lid onto the pot. I filled a shallow pan with garden soil, as the instructions on the Boilex say specifically to seat it into the soil. I placed the Zip fuel block onto the soil and lit it with a match. I then seated the Boilex stand around the block and waited 30 seconds to place the pot on top. I recorded the temperature of the water throughout the burn time.
Test 2: 14g Esbit hexamine tablet in Bleuet 3-piece set
As in Test 1, I used 250ml of cool water in the Bleuet pot with a temperature probe and lid. I placed this over the Bleuet cooker with the sliding door in the "open" position. I lit the cube with a lighter, and recorded the temperature throughout the burn time.
Test 3: 7g Coghlans hexamine tablet in Bleuet 3-piece set
Exactly as Test 2, except with the Coghlans tablet.
Results
These were the final results of the boil test:
The Zip+Boilex setup reached a boil in 13m05s and continued boiling for a further ~25m.
The Esbit+Bleuet setup reached a boil in 7m40s and continued boiling for a further ~10m.
The Coghlans+Bleuet setup did not boil, but it did heat water for nearly 10m.
Observations
Boiling:
The Zip+Boilex was significantly slower to boil than the Esbit+Bleuet. However, the fuel block maintained a steady heat output for more than 35 minutes. This is more than twice as long as the Esbit tab, which burned for approximately 15 minutes. The Coghlans tab did not bring the water to a boil. However, it maintained nearly the same heating rate as the Esbit tab while it was burning. If a second Coghlans tablet were added to the cooker at ~10 minutes, the heating would continue on for nearly 20 minutes, which is a slightly longer time than the single Esbit lasted. Perhaps the Esbit could burn for 20 minutes as well, if it were split in half and burned in two additions.
Burning characteristics:
The Zip+Boilex system left a small (almost negligible) amount of soot on the bottom of the pot. This was easily wiped away with a damp cloth. I noticed that the Zip system burned with a barely visible blue flame throughout most of its burn time. Once when I lifted the pot momentarily to verify that it was still burning, the flame flared up yellow, and produced some smoke. As soon as the pot was replaced on the stand the yellow flame died down. When the fuel burned out, it left a grey ashy hollow shell behind.
It was very clear to me that the Boilex pyramid was heavily influencing the burn in other ways, too. For example, the side of the fuel closest to the match/lighting hole near the base of the pyramid produced a small yellow flame (about 1 cm tall) throughout the burn. At the level of the upper holes, I could see a diffuse blue flame throughout the chamber. The restriction of oxygen clearly throttles the burn.
The Esbit tablet left a shiny deposit on the bottom of the pot and a small amount of blackening. This was removed mostly with a damp cloth, though it required somewhat more scrubbing. The tablet burned consistently and left very little residue.
The Coghlans tablet also left a small shiny deposit on the pot, and also required some scrubbing. There was a small puck of leftover material in the cooker.
Overall thoughts and conclusions
It seems that the Zip fuel depends on air control by the chamber in order to perform well. When it was contained within the pyramid and under the pot, it burned slowly and relatively cleanly. As soon as I lifted up the pot on top, a sooty yellow flame appeared. When used as directed under controlled conditions, the Zip+Boilex is a very good performer. This is especially true if you want a longer, controlled cook time. For example, I could see this combination being excellent for cooking food directly on top of the heat source, rather than simply for boiling water at maximum rate.
I do worry that it may be sensitive to wind. However, this is also true of hexamine, so it's not clear that Zip fuel suffers moreso.
I have seen on Zip's marketing materials that they claim it is faster than hexamine. In their own test: [video=youtube;HZV5Xl6erFg]https://www.youtube.com/watch?v=HZV5Xl6erFg[/video]
they seem to boil much faster than I did. Perhaps this is because they're using sand/steel under the fuel. In my test, I used damp soil which may seal the lower edges better to restrict the air more, and which may directly keep the fuel block cooler.
Overall, I found the Zip system to have a few advantages over the Esbit+Bleuet. First, the fuel lacks the fishy pong we all know and love
. Second, in controlled circumstances it burns for a long time at a decent heat that may be very useful for proper cooking besides boiling. Third, when controlled, it cleans up easier than hexamine.It also has one big disadvantage, however. The Zip system appears to be very sensitive to the cooker it is used within. As described in David Morningstar's post linked above, when burned in a Crusader cooker, it burns hot and sooty. Clearly one cannot simply replace hexamine with Zip straight across and expect nothing but positives. Hexamine, on the other hand, seems to be a lot more cooker-indifferent (but maybe not? Hmmm....)
Would I switch over to the Zip system? I don't know, but even if it were more readily available to me, I doubt it. Hexamine is just too cheap and ubiquitous to abandon. But if I could find it, I can easily imagine that I'd pick up a few boxes to use when conditions suit it.
Last edited:
