What's the point of compression?

Posting this question in the Lightweight Zone because I suspect the answer has something to do with minimalism.

Why compression sacks? I get reducing weight, but what's the point of reducing size of a given item?

I assume that compression sacks weigh more than an equivalent non-compression variety, what with the extra buckles and webbing and whatnot. So presumably there's some tradeoff to the increase in weight carried.

When I read Colin Fletcher, 20+ years ago, he suggested avoiding packing each piece of gear too tightly, so that all the pieces would smush together nicely in the pack, thus maximizing internal space used. Has gear changed since then in ways that obsoletes this theory? What other some other theories that apply here?

I think that the point is to be able to carry a smaller pack. The weight is for sure an issue, however, I think that if you can compress your gear to a certain point that you may even save "pounds" over all thus not only reducing the size of pack needed but also reduce the amount of weight that you are carrying...sabre11004...

I use compression sacks for two reasons: 1) I am small and packs that fit me simply are small. Compression sacks allow me to fit all gear inside and not have to hang stuff off the outside. 2) Weight distribution in your pack is just as important as total weight. Poorly distributed weight feels much heavier. Compression sacks keep the center of gravity of the pack closer to your back -thus less of a "lever arm" factor that pulls you backwards. As for weight - I use the light REI or Granite Gear ones - they really do not weigh much more than regular sacks. I use one for my sleeping bag and one for clothing.

I use dry bags that basically act as compression sacks. My primary interest, though, is keeping my critical insulation (sleeping bag, spare socks, insulating clothing) dry at all times, especially should I again fall into a creek! The Sea-to-Summit Ultra Sil bags that I bought almost 2 years ago work just fine, although earlier models had serious leakage problems. I'd never trust any dry bag without testing it first, though!

I gave up using a pack liner because I kept fighting with the thing--I'd push an item down into my pack and it would pop right back out at me!

Your Mileage, of course, May Vary. Some prefer a bigger pack so that less compression is required. I prefer the smaller pack.

Just be careful with the insulation for puffy stuff (either down or synthetic)--over-compressing it for extended periods can damage the loft. My sleeping bag is the first item out after my tent is pitched and the last item packed before the tent comes down. If it's a many hours' or days' drive to the trailhead, it travels in its big storage bag. I don't pack it until the trailhead, and I unpack the sleeping bag as soon as I get back to the car.

EDIT: Also, compressing something into brick-like status makes it harder to fit into the pack. Better to have it a bit bigger and have it "give" a bit so as to conform to the space in the pack. That's Colin's advice, too!

I still follow St. Colin's advice and avoid the too-small stuff sack, to the point that I stuff my down bag into the bottom of the pack, without a stuff sack (unless I'm knowingly headed into heavy rain, then I use a big silnylon non-compression sack.) I've found that, using the other gear, I can then compress the bag as much as I need to (or let it fluff up to maintain the volume/height/center of gravity where I want it.)

I briefly used a compression sack when I (also briefly) used a synthetic bag - it was the only way to keep it small enough to lash onto my Camp Trails Adjustable II pack - ah, the good (?) old days!

I've read all 4 of the Complete Walker series, like you starting over 20 years ago, and I've found that virtually all of his technique is just as valid now as it was then. Gear has changed a lot, but basic methods haven't.

I'm with WD on this one - for the same reason - I use the OR helium sacks - one for my sleeping bag. and often one for clothing - especially if I'm doing an extended weekender with a very small (i.e. 30l) pack. i.e. above treeline with my little MEC alpinelite 30 bag.

I also prefer my sleeping bag in a little brick in a silnylon sack rather than loosely packed st-colin style in the bottom, as if/when any water gets into the pack I don't end up with a wet bag/clothing.

However many quite sane and experienced people will disagree with me - I find this is one of the things many people have differing styles with.

Instead of using a liner, I use "sacks" for every thing. In my experience, I find that most water proof bags are water proof but after compressed a little, They do tend to swell a little by filing back up with air after being compressed. So how I manage this is to pack my backpack a "little" loosely. Then after a few minutes the air starts to fill the water proof bags and in the end the backpack usually ends up packed pretty tightly. It lets every thing stay right where you put it and you never have any movement back and forth as you walk and it makes for a pretty solid packed backpack. I can remember years ago (back in the seventies) when I used an external frame pack, I used to hate after getting the pack packed, every thing seemed to want to move around inside the pack. Not any more with the philosophy that I now use. Seems to work great and the best thing about it is that it works every time...sabre11004...

Smaller pack? I use small packs with no compression. Sometimes I stuff the sleeping bag free to fill space away from my back - especially late in a hike when the food bag is smaller. Things that don't suffer from compression (tarp, hammock) get smashed into small stuff sacks. Everything else gets loosely bagged. At the same time, I don't think good down suffers much from heavy compression. So if you want a pack full of odd-shaped bricks, go for it. Hike your own hike.

During WW-II, down sleeping bags were part of the survival gear for pilots in some of the theaters; a late uncle of mine who flew The Hump said that he had one as part of his gear. The sleeping bags were vacuum packed into a small metal can; a bit smaller than a canned ham. I bought one at a surplus store, still in the can, in 1956. I took it out of the container, let it loft for a few days and it seemed to fluff up real nice. They didn't seem to be made for durability, the one I had only lasted a couple of years but the down was still good; it was the fabric that didn't last.

I love the image of a sleeping bag in a can. It reminds me of the old Snakes in a Nut Can gag.

Thanks everyone for the thoughts. Lots of interesting ideas to chew on and experiment with.

I always consider a compression sack a heavy way to overcompress and ruin a piece of insulating gear; and it's usually a piece of insulating gear that was the cheapest, but not the best choice. I just put my sleeping bag loose in a trash compactor bag, and let it fill up the rest of my pack volume. And most manufacturers of quality down gear will tell you not to overcompress it. I know WM says not to use a compression sack, or stuff sack smaller than the one they send.

1) Trash bag into pack.
2) Sleeping bag into trash bag.
3) Pack everything else on top and compress as needed.

No need for a compression sack. IMO if you "need" one then what you really need is a bigger pack.

No comment...sabre11004

Or possibly a sleeping bag smaller than the Coleman 10 pounder?

LOL That might help too.

I was thinking more along the lines of when someone buys there pack first instead of last and then finds out their gear won't fit. Or going from summer to winter gear and trying to compress your gear to fit in a pack you use for summer gear. Which, ironically, is when I'd be most concerned about over compressing insulation.

It can be hard to find packs large enough. Couple that with trying to find a lightweight large pack, and it is nearly impossible to find anything off the shelf.

An ultralight winter sleeping bag is a pretty monstrous thing. It doesn't matter how high the fill power of down is, such a bag will never pack very small. Things get even worse when a WPB fabric is used for the shell of the sleeping bag.

By the manufacturer's definition I guess you're right. But for me a "winter" bag is a Golite Ultra 20 (a.k.a. Ulra 30) and in the summer I just use my poncho liner or nothing at all (unless I vacation North for cooler weather).

It isn't winter for me until I need a -20F or below bag.

20F bags are for summer!

When I lived in TX I was like Larry. I have a 60F bag that worked great for 3 season. Now in Utah, a 20F bag is a good 3 season.

Also it can kep the center of gravity closer to your back.

Chris

You really don't have to be real concerned with compression if, that is, you know what you are doing. I have compressed many insulators and have never had a problem with any of my gear failing. Back in the seventies, you had to learn to compress everything because everything was "HUGE", and weighed a ton. I can remember when I did carry an external frame pack and starting out, some times weighed in at around 50-60 lbs. If that were the case today, I probably would no longer be backpacking because I just can no longer carry a load that large. I can remember getting lost up in the GSMNP back in the seventies in a huge snow storm and without any food and water our packs still weighed in at around thirty pounds. It was just the nature of the beast back in the day. No body seemed to mind carrying packs that heavy, but then again that's all there was to carry, so you dealt with it. You look back at the good old times but in this instance the newer times are the best because you have lighter gear that is much better in quality than the "good old days"...sabre11004...

Just a couple of thoughts.

Perfect down - containing only plumules and no quills - will recover from severe (huge and unimaginable)compression. Try it if you have any left from a project. But compression will push quills through the shell of bags and garments. It also can crimp quills - which can cause lower loft down (450 to 550) to lose loft because it relies on the quills.

Framelesss packs hold shape better if insulating garments (including bag) are stuffed free to fill space. If the insulation is toward the front of the pack it will hold denser items such as food closer to the back.