I went for a couple of nights wild camping last week and took my charcoal stove, after making a few more adjustments. I swapped back to the original stove can with a big opening, so that it could be used as a wood stove as well if necessary. I then put a second grate in it just above the door level, on which to put the layer of charcoal, and, at the last minute, cut an inch or so off the top of the stove can. All of this meant I had a neat little wood-burning hobo stove, or that same wood could be used to light charcoal on the level above for a cleaner longer burn with less hassle, and the kettle, suspended on its cradle from the upper “chimney can” would be closer to the heat source in either case. There was a risk that this shortening of the whole would reduce the updraught through it, but I thought it would be a better net result.
There are a couple of disappointments: first of all, it dawned on me that I’d been thinking of charcoal as one of those fuels that should be easily available during hiking, which is true, but usually in 4 or 5 kg bags, a lot more than you’d want to buy when hiking; secondly, my estimates of how much I’d use were rather optimistic. The latter was at least partly because I boiled more water than expected, however, and I’m not sure how it would compare, weight for weight, with gas or alcohol. Unfortunately, my fuel arrangements were unauthodox in past solo camping trips, so I’d have to buy another type of stove to make a decent comparison.
I’m not going to switch back to a Coleman F1 or dig out the trangia just yet though. An ultralite gas stove might be more efficient, quicker and cleaner in use, but I have subjective reasons why I’d rather stick to wood and charcoal. I go out wild camping to get closer to nature and the “simple” life (in some ways more complicated): turning on a gas knob and boiling water in 4 minutes with a mechanical roar doesn’t compare well with the gentle crackle of wood, even if I have to work harder and wait longer. A real fire is almost a living companion for the time it’s burning. Where it’s safe and responsible to do so I’d rather have a little open wood fire between stones than a stove of any kind.
Then there’s the ecological differences. I don’t know, to be completely honest, just how bad butane and propane are to produce, put in metal cans and transport to the shop, or how difficult the cans are to recycle, I just know that it’s bound to be a lot worse for the planet than the renewable resources of local twigs or commercially produced charcoal. Again, this is a very subjective, emotional concern, since the overall amount of butane I would burn in the next 10 years would be trivial compared to my car’s petrol consumption next week! Still, I don’t like burning gas at camp, and if I could be bothered to run my car on charcoal I would.
What I need to do is experiment more. It’s possible that the second design of stove with large holes all round the base was better (although I’d not like to lose the dual-fuel ability of the stoking hole for putting wood in. It might be worth going back to charcoal briquettes to get a longer, steadier burn, or mix that with the natural charcoal. It’s early days. My experiments have been rather approximate. I think I took about 250 g of natural charcoal, and I burned it in about 5 sessions, but sometimes I got two “kettlefuls” (about 250 ml) boiled, or the second one hot enough for coffee, other times just one. I was in the woods, not a laboratory. Sometimes the stove seemed to work extremely well, as in the video below; other times I struggled to get the wood to light, or the charcoal to light from the wood. As a wood-burning stove it was just as hit-and-miss, and maybe this was more due to the dryness of the twigs I used on different occasions. It was also very clearly affected by the wind, being helped by a steady breeze into the door, without which I resorted to blowing in it. It may be worth trying to increase the air input holes, although there are quite a number around the base. I wonder about lifing the stove up further on legs and putting holes in what is now the base and ash collection pit, although this translates in effect to making the wood grate higher up in the stove. I also wonder if the inch I removed from the stove did reduce the draught, and whether to add that height to the top (also acting as extra insulation for the top of the kettle).
One particular issue was the amount of charcoal dust among the pieces, which of course I ended up with in the bottom of the bag. If this were eliminated, the same weight would have done me a hot breakfast on the third morning, but as powder it’s very hard to use, mainly because it falls through the grate to mix with the priming wood, or forms a blanket all the way across the charcoal grate, choking off the air. I plan another trip before long, and in the meantime will do some slightly more scientific testing in the back garden.