[pct-l] Bear cannisters, etc.

[steve_peterson at sbcglobal.net (Steve Peterson)]

Sharon & Chuck Chelin wrote:
> Good morning,
> 
> To optimize the space in a food container it is important to pay attention
> to volumetric density and Caloric density.  Volumetric density is how
> tightly the food can be packed into a container, meaning with the least air
> space.  The shape of the food items is important here.  Except around the
> edges of a cylindrical container, square or rectangular shapes pack more
> tightly than rounded items.  For example, chocolate-nut fudge squares pack
> more tightly than my long-time favorite peanut M&Ms.  Most chips have very
> irregular shapes, and take up lots of space for their weight.

I agree with this, but I have found that there is always space "left over" into 
which you can squeeze some things like M&Ms--I just put them in last (or a 
litttle at a time as the can fills up) rather than first. I considered, but 
didn't try, just pouring the pasta stars in and letting them fill all the gaps. 
I bet I could have gotten all my pasta in for "free" using just the space around 
the other items that otherwise went unused. Getting it out, of course, would 
have been a pain, and that's one reason I didn't try it. Also, don't be afraid 
to "reshape" things like candy bars or cheese--you can morph them into amazing 
shapes without breaking the packaging.

> 
> Caloric density is how many Calories there are per the few cubic inches you
> have.  Go with foods that have lots of fat, which has 9 Calories per gram
> compared to 4 Calories per gram of carbohydrate and protein.  The very best
> volumetric and Caloric density would be container poured full of pure
> vegetable oil, but nobody could live on that.

Nearly as good would be solid chocolate and I know people who probably *could* 
live on that! :-) Still, on a long hike, you do need some protein and some 
fiber, etc. so I personally try for something like a 40:30:30 ratio, maybe 
upping the fat a bit to get the calories I know I'll need.

Paying attention to the caloric density (calories per unit volume) is subtle but 
important because most of the time hikers tend to think in terms of calories per 
unit of weight (calories per ounce, for example) and we tend to take things that 
are *light* but full of calories. As Steele-Eye points out, when using a bear 
can, the thinking needs to change to foods that are *small* but full of 
calories. Here's the not so obvious point--the two are not the same: sugar 
crystals do not contain as many calories per cubic inch as (say) jam, does, even 
though you'd be tempted to take sugar rather than jam because it's lighter. Many 
foods are like that: tortillas contain way more calories per cubic inch than 
bread (and even "dense" crackers) -- in non-bear-can country I'd take crackers 
because I'm looking for the *lightest* load, but with a bear can I use tortillas 
because with it I'm looking for the *densest* load (volume unfortunately being a 
tighter constaint than weight).

>   If most of your food
> fits in the bear can you will do OK.  Remember that you will probably burn
> off one or two pounds of food before you get from the trailhead or resupply
> point to the places where the pesky bears patrol.

But if you hike immediately into bear country, remember that the first day's 
garbage (but not the first day's food assuming you've eaten it all) has to go 
into the bear can that night.

--Steve