Monday 18 August 2014

Ascent to madness: In which I climb up my own backside




Warning and Disclaimer: This post is about cooking and stuff whilst backpacking.  Like any meal it should be taken with a pinch of salt.  Fellbound does not accept any liability for any loss, injury or damage that results from this blog post, howsoever caused.  He also wishes to remind readers that he is supported by a crack legal team (Messrs Cosh, Basher and Hardcase) who will deal with you as deemed appropriate by Fellbound if you so much as suggest that this blog post proves that Fellbound is an anally retentive cretin who needs to count grams less and get out on the hills more.  Finally, he needs to point out that any gear referred to in this blog post was purchased by Fellbound using his “gold plated public sector pension” (© Daily Mail, Daily Express, Daily Telegraph, The Sun, The Times etc., in fact all national newspapers except The Grauniad, The Daily Mirror and The Socialist Worker).  Fellbound is still willing to accept any offer of free gear (which remains remarkably absent in the Fellbound household) from any reputable manufacturer or retailer and promises to review any free gear if he can get round to it.


 
Using 5 grams of gas for an early morning brew: well worth it
An interesting post on Alan Rayner's blog recently about the TGO Challenge resulted in a few comments about the respective efficiency of gas and alcohol (meths) stoves in relation to the weight that you have to carry using these systems.  The perceived wisdom is that on longer trips gas is lighter than meths.  Whilst I have always tended to believe this, I think that the position is rather less straightforward.  This is not least because the comments on Alan’s post related to the weight of the fuel and did not refer to the weight of the cooking system itself, nor to the frequency of resupply stops.  So whilst walking Hyperdog along the lanes this morning I pondered on the issue.  When I got home I got the kitchen scales out, set up several spreadsheets and developed what will, I am sure, become known in mathematical and backpacking circles as “The Fellbound Theorem”.  In short this can be summarised as follows:


“When counting the grams for cooking your calories there is no clear answer as to whether gas or alcohol is lightest so your best bet is to eat your dinner and enjoy the view”.


This earth shattering conclusion is underpinned by a set of assumptions based on my own equipment and my particular way of cooking and frequency of brewing up.  The outcomes might be completely different for others.  It does not take account of factors such as the speed and cleanliness of gas, the reliability of meths stoves, or whether you like the odd slug of meths as an aperitif.  My findings now need to be the subject of peer review to test their robustness.  You, dear reader, are the peers.


Assumptions based on my own way of doing things (aka “the right way”):


  • There is a minimum amount of weight you have to carry for the stove set up even before you add fuel. I will refer to this as the “stove base weight”.

  • My gas stove base weight: A little Optimus thingy (94gr), with an Optimus windshield (64gr) and canister feet (24gr) for stability, gas cartridge.  Depending on length of trip and resupply possibilities the cartridge will likely be either 100gr (weighs 200gr when full) or 150 gr (weighs 380 gr when full).  So gas stove base weight =  282 or 332 gr., dependent on size of cartridge carried.

  • My meths stove base weight: Traildesigns Sidewinder cone in Tyvek sleeve (37gr), aluminium support pegs (14gr), Trail Designs stove (16gr), 500ml meths bottle (10gr).  So meths stove base weight = 77 gr.

  • So the base weight for the two set ups is either 77gr for meths or 282/332 gr for gas.  At my rate of fuel use (see below) meths is definitely lighter for a 2 or 3 day trip.

  • Amount of cooking: 4 brews per day, plus one boil for instant porridge, one for an instant soup and one for a dehydrated meal.

  • Rate of fuel use:  On the TGO Challenge I ran out of gas using a 230 gr cartridge on the 9th day of cooking ie 25gr. of gas used per day. Meths use is a generous100 gr per day.


Findings:


Right let’s put all this together.  I will not try to embed my fancy spreadsheets because I don’t know how to, so here are some charts created from these and based on the above:

 


The first chart is based on a two week trip in the wilderness entirely unsupported, with no resupply of fuel.  You therefore need two gas cartridges, a small one and a large one (that situation is 'Gas 1' in the chart).  'Gas 2' is where in that wilderness you come across a conveniently located waste bin on the very day (Day 5) a gas cartridge empties so you can chuck it away. 

 


The second chart shows a more likely situation on the TGO Challenge. This assumes you can buy extra fuel every 4 days. Note that resupply every 4 days is the optimum for gas if using 25 gr of gas per day as it allows the small 100 gr cartridge to be carried, although you would be running on empty when you got to the shops.



What both of these charts show is that on certain sections of the trip you carry less weight if using gas; at other times on the trip you would be carrying less meths.



Of course all this is very crude and needs refining.  For example, the charts show that for a TGO Challenger meths is heavier in the earlier days. However, Challengers tend to walk shorter days initially, and longer days later on. So what I need to do next is set up some spreadsheets to examine weight carried against the numbers of hours on the trail on each day of the trip. This information could then be examined against the numbers of calories that would need to be consumed to have the energy to carry these weights for these periods, which in turn would have implications for the weight of food to be taken on your trip. All of this is clearly a suitable topic for a PhD so I must start to put together my research proposal……

22 comments:

  1. On your re-supply days you wouldn’t bin your existing canister on the 4/5 days if you have any gas left. So then you would be carrying 2 canisters for a little while. I think.
    The other thing with meths is:- if any challengers are running out of meths you could share your excess, as i did. But with gas you can’t. Unless you made somebody a meal of course but that is pushing it a bit.

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  2. That's absolutely right, Alan. Of course the whole analysis is ridiculous! You takes what you takes and likes what you likes and eats what you eats.

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  3. Have you factored in the additional calories burnt keeping yourself warm whilst waiting for the meths stove to boil your water ? This would need to offset against the calories burnt vigorously shaking your gas canister as it becomes progressively empty.

    Either way, my votes with going down to the nearest pub for a steak and ale pie.

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    1. Hello John

      I am very pleased that you have thought about this and are giving the matter the weight it deserves ('Weight'! Play on words there. Geddit?). Unfortunately, John, your logic is "all to cock", as Aristotle would say to his rivals. I will explain:

      Let's say meths takes four more minutes to boil your pan of water than gas. You would not expend more energy waiting for the meths to boil as your preceding meal would have also been delayed by four minutes. Thus, the time gap between eating is identical for each fuel type. Still, a good try. I may take you on as my research assistant when I start my PhD. It is to be entitled "Backpack Cooking and Pedantry in the Wilderness Environment". It's sure to get EU grant funding.

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  4. Your way of doing things can't be "the right way". JK has already claimed that distinction.
    Norma

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    1. Lovely to hear from you on this blog, Norma. I was very interested to read your comment about 'JK'. I think I can work out who you are referring to. There are two possibilities if he believes his way is always the right way. Firstly, JK may do everything in the same way that I do. Or secondly, he is living in cloud cuckoo land and is plain wrong. I suspect, alas, it will be the latter. I assume that by now he is well on his way to Patterdale on his latest venture

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    2. Yes - you have the correct JK. He is leaving Grasmere as we speak.
      Norma

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  5. It came to my attention last week, that rather than do a multi day trip, it is much easier to do day trips with a bloke wot owns a house near Penrith.
    Not only do you not have to carry any fuel at all other than maybe a dram, but he also supplies you with food, and a bedroom with a bed where all your gear can be laid out.
    Plus he provides a taxi service, and when not accompanying, does the hoovering while you are out.
    No sir, no more of this base weight shit for me.
    I am all for camping like the 3rd little piggy.

    I'll be BACK! :-)

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    1. That sounds a good system. You need to send me his address so I can stay there too.

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  6. When I used to go mountaineering in the former USSR, the Russian climbers had a different tact. They would refil their gas cannisters and reuse them rather than binning them. Unfortunately it had a couple of downsides. Firstly it meant lugging an industrial sized propane bottle to basecamp to refil them from. And because they used gas tapped from rotting cabbages, it burnt with an odd green flame and your tent always took on the aroma of post Christmas meal flatulence. They also had a tendancy to explode in the tent porch.

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    1. John

      The drawbacks of that system in the former USSR do appear to outweigh the advantages, although there should be some way of recycling gas canisters in this country.

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  7. Fascinating David.

    I carried a 450g (645g) canister at the start of the PW which was a little excessive. Now I wasn't short of fuel for cooking but I was short of alcohol sometimes.

    I'm liking the meths idea especially as it could do 'double duty'...hic!

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    1. I'm not certain medical people would encourage that, Wayne.

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  8. Have you thought about eating only Primula on oatcakes so saving immense amounts of fuel? How would that affect your spreadsheets?

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    1. I need a hot meal each and every day, Ian. I understand that the fat content in Primula makes it suitable as an emergency fuel in a meths stove, though.

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  9. Nice analysis David. I'm currently experimenting with that fuel4gel stuff. It strikes me as having all the benefits of Meths but with the added advantage of being able to spread it on your pitta bread or just consume neat, not unlike a vodka jelly a few weeks past it's best. The consistency is it's unique selling point.

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    1. I haven't yet tasted Fuel4, Steve. I did purchase some of their gel and it just left a nasty hard residue in my burner. I haven't tried the liquid Fuel4 yet. Some reports says it's not as effective as meths.

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  10. Having just won 6 packs in a twitter competition I will be giving it a try soon. I'm intrigued as I never really got on with Meths.

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  11. Talisker or an Islay is far better, Steve. Although a tad more expensive.

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  12. I'm a little late to this David,

    Love the graphs, but would be more informative if the fuels were given equal weighting. But, I think your daily fuel use figures are quite skewed in gases favour?

    e.g. 25g of gas boils around 1.5l of water (8g/500ml) on a non Jetboil type stove. Meths (which is less dense than water) at my stoves burn rate = 20mlfuel/500ml boil = 17g/500ml so 100g of meths will be giving almost twice as much boiled water as 25g of gas! Like for like, really only need <60g of meths a day.....Even at a thirsty (Evernew/Trangia) meths stove guzzling rate it would only be 75g/day. Hope this is of interest! (Yes this is a displacement activity!)

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  13. Hi Anonymous

    Arghhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh!

    My brains boiled out of my ears when I read your comments. Like me you need to get a life :-)

    However, you make some valid points. I calculated my gas use for the above simply on experience - weight of gas in canister divided by number of days a canister lasts for me. Clearly this can vary a bit. As for meths, I haven't used it that much in the field so did some test boils then estimated how much water I would boil each day. In fact I took meths on my trip two weeks ago. I got through 120 ml a day for 3 days. I brew up a lot but was also wasting it as I didn't have the experience to estimate the right amount to put in the stove per brew and generally the stove was still burning long after the water had boiled.

    Thanks for the interest you showed in my post. I would suggest that better displacement activity might be to pop outside and talk to the flowers and bumble bees and things. That's what I'm off to do now.....

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  14. Hah. Thanks David :D I went to feed the pigs instead, then bashed some nails out of some wood. I might even do some work soon too! Just read some of your TGO report and realise we met at Shielin of Mark. After a chat in the hut, we went off and camped downstream a couple hundred metres . Cheers. Mole

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