I have considered it, decided not too. But I might change my mind, they are cheap.

The problem I see is that a sack gets smaller as you eat the food that was in it, and that aluminum sheet would keep the sack big. Thus, one of the big advantages of the Ursack over a hard canister disappears.

If I traveled to some places where the aluminum was needed for regulatory purposes, I would have bought it years ago. I have no such plans. If I need it later and they are no longer available, I would probably rent or buy a hard canister then.

I use an Ursack primarily for protection against smaller critters, like mice, raccoons, and chipmunks that can get into your food. And also because if a bear gets my Ursack, they might crush my food, but I am not training the bear to go to campsites for a source of food. In that case, my crushed food that a bear did not get to eat is a benefit to future campers, not me. There is no question, a hard canister is better protection, but I have never had a bear get to my food yet, so I only would get a canister if regulations required it.

I am packing for a backpacking trip, leave in about a week. Yesterday, my Ursack (XL size, 15 liter), a REI brand 15 liter drybag, and six days of food weighed 5.29 kg, or about 11.7 pounds. The bag had a little empty space in it, could hold more than six days. When I have used that Ursack for a nine day canoe trip, the Ursack held about 7 or 8 days of the food. Theses quantities are all for a solo trip.

Backpacking, I carry food that just needs to be heated. Butane stove, minimal fuel weight or use. And light weight foods. That said, my Dr has cautioned me that I need to get adequate protein on such trips, so I have a couple small packets of meat every day too. Along with a 20 gram protein bar per day.

Canoeing or bike touring, besides dehydrated foods, I am more inclined to carry food that uses a fry pan (eggs, fried meat), or maybe pasta that needs extended boiling. Liquid fuel stove on those trips if I did not fly somewhere. Bike touring, might buy canned foods too, such as a can of soup or chili, etc. The weight and bulk rises for such trips compared to backpacking.

Packed up my backpack yesterday to wear on a three mile hike, about half of that was through a hilly park. To get the food to fit well in my backpack, I had to take about a third of the Ursack contents out to pack elsewhere in the pack. A canister would not fit well in that pack, and the aluminum sheet in the Ursack would not fit well either if I had that. On my trip, I have one resupply at a mid point, so about a week and a half long backpacking trip.

These days I limit myself to no more than 4 days (maybe stretch to 5, but probably not) between resupply. That way I can use a canister that will fit in almost any pack other than very small ones. My BV450 will easily fit in my Flash 45 pack.

BTW, as far as the Ursack not gettin smaller with the liner... You could do what some canister users do and pack it full of other gear as it gets empty. Some even routinely leave the food out during the day and carry gear in it then.

Yeah, but that only really works with a small enough canister to fit in my pack well.

Planning out these resupply points is a big enough hassle that I am limiting it to one. And that impacts my pack size. Lock up my bike at end point, I then drive to the resupply point, get a shuttle ($110, reservation made weeks ago) to where my hiking starts. Hike to my vehicle where my re-supply stuff is stored and resupply. Then hike to the end point. Next day ride my bike to my vehicle to retrieve it.

Here's my setup with the Bear Keg (11.7 L). It'll hold food, the clothes used for meals and toiletries.
Kitchen stuff is in one stuffsack that can be hung up if necessary.

https://cimg4.ibsrv.net/gimg/bikefor...8a0b3c5c00.jpg

Yep, I get that. It limits my choices a lot of times for backpacking or to a lesser extent for bikepacking in the boonies. I wind up passing on routes that i otherwise want to do because I am no longer willing to carry as much as I used to and either can't manage frequent enough resupply or it is just too much trouble. I have done multiple ones (I think three was the most for one trip) if it was a matter of using mail drops for a trip I really wanted to do. I have not done caches where I drove around stashing stuff, but I might do that with water for a couple places I want to ride off road in the south west.

Water resupply can be a bigger problem than food in many places. There are quite a few arid routes that I'd really like to ride but water is heavy and you can't go far without it. I don't think that there are the same issues with bears and water as there is with food, although we do have raccoons that will tear into our fresh water jugs when we are canoe camping in some places in the everglades.

Just speak firmly to a misbehaving bear as if it's a bad dog and escort it away from your stuff...I think the fellow could have pulled it off if he hadn't stuck out his arm to point out the gate, and the bear was reluctant to cross under that threatening sword of Damocles.

https://boingboing.net/2023/09/07/pe...tch-video.html