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……
