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Ursack AllMitey Bear Bag Review

The Ursack AllMitey is a bear-proof and critter-proof food storage bag for camping and backpacking. It differs from Ursack’s other food storage bags, (the Ursack Major, Ursack Major XL, and Ursack Minor), which are either bear-proof or critter proof, but not both.

ModelBear-ProofCritter-ProofVolumeWeightPrice
Ursack AllMiteyYesYes10.65L13 oz$135
Ursack Major XLYesNo15L8.8 oz$100
Ursack MajorYesNo10.65L7.6 oz$85
Ursack MinorNoYes10.65L5 oz$100

If you’re not familiar with Ursacks, they’re soft bags made with super-tough Spectra and/or Kevlar fibers that bears can’t pull apart and critters can’t chew or claw through. There’s also no need to hang them high up in a tree, at least in the case of the AllMitey, because the bag is impenetrable by bears and critters. An Ursack is a big improvement over a traditional bear-bag hang because many, if not most backpackers and campers, do such a poor job hanging their food bags so an animal can’t bring it down. Once down, it’s easy for an animal to rip open a stuff sack, eat, or foul all the food inside.

While an Ursack AllMitey has many advantages over a hard-sided bear canister, such as lighter weight, better packability, and reduced volume as you eat your food down, it’s still not universally approved for use in national and state parks that require visitors to use a bear canister. Additionally, the Ursack AllMitey is not crush-proof, it’s not leak-proof, and the outside of the bag will absorb rain, which sucks when you have to pack it next to the dry stuff inside your backpack. This is true of the Ursack Major and Major XL as well. Peoples needs and risk tolerances vary, so none of these issues are absolute showstoppers, but the AllMitey still falls short when compared to a hard-sided bear canister.

A terrible food hang just two feet off the ground!
Most backpackers do a poor job hanging their food bags out of reach.

Personally, I doubt whether the Ursack AllMitey will ever be universally approved for use in areas that require hard-sided bear canisters. I’m just being a realist. I think its biggest benefit is as a replacement for traditional food hangs. I’ve been using an Ursack in this manner since 2007 and doubt I’ll ever hang another bear bag in my life. I prefer the speed and convenience of using an Ursack rather than the clown show of trying to throw a rock attached to 50′ of bear bag cord before the sun sets. When you use an Ursack AllMitey, you can count on your food being intact in the morning. That’s not the case with a traditional bear hang.

Construction

The AllMitey is made with Spectra so that it’s bear-resistant, and Kevlar, so it’s critter resistant. Spectra is strong enough that it can resist the pulling and clawing action of bears, while Kevlar bags can rebuff small animals which have sharper teeth than bears. Ursack’s other bear bags, the Major and Major XL are only made with Spectra, while the Ursack Minor is made with Kevlar.

The exterior of the AllMitey, the Major, and Major XL is a black colored Spectra. Older model Ursacks were un-died and white or off-white in color. The Ursack Minor is made with cream-colored Kevlar and closes with a stiff velcro strip at the top. If you examine the AllMitey closely, it’s basically an Ursack Major on the outside with an Ursack Minor sewn inside, providing multiple layers of protection, but at a lower cost than if you combined the two yourself.

Older model Ursack bear bags were colored white or light green while the latest models, including the Ursack AllMitey, are black. Research showed that customers prefer the black color because it doesn’t look as dirty when used.

Smell-Proof Liner Bag

Ursack recommends lining the inside of their bear-proof and critter-proof bags with a smell-proof plastic bag called an Opsack (odor-proof sack), which is included with the Ursack AllMitey when you buy it. A bear’s sense of smell is 7 times that of a bloodhound’s and 2100 times better than a human’s. and the use of a smell-proof barrier helps prevent your food from being detected.

Unfortunately, these bags are virtually impossible to keep completely smell-proof in the backcountry, unless you bring a supply of Nitrile gloves with you to handle them with. If you touch the outside of an Opsack after having touched food, it ceases to stay odor-proof. This issue is well understood by the FBI, the CIA and the other government agencies that use Opsacks for evidence collection. They address it by double bagging collected materials, instead of relying on one Opsack, to prevent evidence contamination.

Nevertheless, I still like using an Opsack to line my Ursack because it’s a heavy-duty plastic bag capable of keeping the inside clean and dry, in the event that any of my trash or food leaks. Ursacks are washable, by the way. See the Ursack website for washing instructions.

The AllMitey and all Ursacks come with a smell-proof plastic liner called an OPsack.

The included Opsack that comes with an Ursack fits perfectly inside and closes with a Ziploc-style seal. It’s much tougher than a gallon-sized Ziploc bag though and can survive repeated use. I change mine about once a year when the top seal tears and ceases to close. Replacements bags are sold separately.

Optional Aluminum Liner

The contents of an AllMitey, like all Ursacks, can still be crushed by a pissed-off bear. Crushing may sound inconsequential because so much backpacking food is still edible when crushed, but chances are you’ll be storing more than food in an Ursack. For example, I pack all my “smellables” in my bear bag, from my toothpaste and butt paste to my cookpot, inside my Ursack at night. If they were to get crushed or mixed in with my other food, it would severely compromise my ability to eat or cook on a trip.

Ursack sells a 10.9 oz aluminum liner that you can insert to the Ursack Major and Major XL to prevent their contents from being crushed. It can also be used with the AllMitey but makes it impossible to close the inner, critter-proof part of the bag. I consider this a defect because it negates the added value of the AllMitey over the Ursack Major and Major XL. Hopefully, Ursack (the company) will address this issue soon. While I’ve never felt the need to use an aluminum liner in my older model Ursack because Black bears have never disturbed it, it would be a bigger concern if I took trips far off the grid in Grizzly or Brown bear territory, without easy access to a town in an emergency.

Crisscross the drawstring cords and pull them tight (there are two more holes on the opposites side) so there’s no space at the top of the bag

Closing and Securing the AllMitey

When you want to close the AllMitey up for the night, you seal the inner bag which closes with a heavy duty velcro strip that an animal would have a very hard time prying apart. The outer bag closes with a 6′ drawcord that you cinch tight so the opening at the top of the bag is completely closed. When there aren’t any gaps left in the top, you tie a double overhand knot, also called a surgeon’s not, in the cord to keep it the bag from opening. This is a very easy knot to untie. You still need another knot to prevent the double overhand knot from being opened by an animal, which I explain next.

Cinch the bag closed and tie it off with a double overhand loop

You don’t want a bear to be able to walk off with the AllMitey, so Ursack recommends tying it to a tree branch or a stationary object with the remaining slack in the drawcord line, knotting the end with a double figure eight knot. This knot is also easy to untie even if a bear has been tugging at it all night.

Loop the remaining line around a tree or stationary object and secure it with a double figure eight knot.

I usually tie my AllMitey out of sight of my camp because I don’t have any desire to encounter a foraging bear or wild animals at night. Just remember where you put it, so you can find it the next morning. If you can’t find a tree branch to tie it to, tie it to a stationary object like a tree trunk on the ground, making sure to tie a stopper knot like the double figure eight over the surgeon’s knot so it won’t open. If you’re above treeline, cover the AllMitey with rocks or in a worst case scenario, just leave it on the ground and pray that a bear or critter doesn’t carry it off. Bears carry off unsecured bear canisters, though, so I wouldn’t count on it.

The critter-proof Ursack AllMitey is more secure if left on the ground than the Ursack Major or Major XL.

Recommendation

The Ursack AllMitey is a bear-proof and critter proof bag that can be used to protect your food while you sleep on backpacking and camping trips. It’s far more reliable, faster and easier to use than hanging a bear bag in a tree with a 5o’ length of cord and a rock. It’s also the only food storage bag made by Ursack that can be left on the ground overnight or in a mouse-accessible bear box and still provide complete bear and critter protection. I consider this the best use case for the Ursack AllMitey and recommend you switch to it if you backpack regularly and find a traditional bear-hang annoying, time-consuming, challenging, or intimidating.

While the Ursack AllMitey is much lighter weight and more packable than a hard-sided bear-canister, it’s not crush-proof, waterproof, or leak-proof. None of these are necessarily showstoppers in the right circumstances, but they are factors that must be weighed carefully when deciding to choose between using an AllMitey and a canister. The AllMitey is also not universally approved for use in some National and State Parks and Forests, despite being IGBC approved. Check before you assume you can use one.

If you visit an area that requires a bear canister but permits the use of an AllMitey as well, I’d definitely consider using it since it’s lighter weight, more packable, and shrinks in volume as you use your food. While the AllMitey is not a complete replacement for a canister (for example, it makes a poor camp stool), it’s better than lugging a heavy and bulky canister for your entire trip when you don’t have too.

Ursack provided the author with a sample AllMitey for this review.

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29 comments

  1. Great report, but there are some caveats that need to be pointed out. I have read a number of reports of bears that attempted to defeat the sack and, while it is true that in all of the cases the bear was unable to defeat the bag, what he did was chew the heck out of it. In all of the cases the food inside was crushed and in most cases the bear slimed the sack pretty bad. In one case he even bled into the bag. I guess they salivate at the smell of the food. Bottom line is, while the Ursack may have won the battle, it lost the war. Unless you relish pulverized food covered in bear slime, you’re gonna throw the food out anyway. One final point about the OP sack; can’t they make a closure system that’s easy to seal and won’t break after a few uses? Once the bag stiffens up with use, it’s nearly impossible to get the thing closed properly. I just end up rolling the top like a dry bag and securing with an alligator clip.

    PS: I still use the Ursack but I hang it whenever possible. Also, my opinion is based solely on reports I have read on blogs. In all of the times I have used the sack, I’ve never had a bear attack it. This may call for a SectionHiker poll to get to the bottom of this!

    • There are two ways to look at these bags, one as a way to protect your food and the other as a way to protect the bear from getting a food reward. In the reports you cite, it sounds like the bear was denied the food. These animals are very intelligent and learn.

      But like I said, an Ursack isn’t as good as a bear canister for protecting your food. But it is a million times better than a conventional bear hang. If people only used it for that use case, we’d all be better off, including the bears.

    • Last week had an Ursack/Bear incident about 30 miles south of Hanover NH on the AT. The bottom of the bag was about 6.5 feet off the ground and about 5 feet from the tree trunk. The smallish bear leapt from the trunk, grabbed the bag with all 4 paws, clamped its jaws on the bottom of the bag and let go with its paws. Hung by its jaws twisting back and forth! It failed to get the bag, but its canines left nail sized holes and a scary imprint of its jaws on the bag. Darndest thing I’ve ever witnessed, it sure got my adrenaline flowing. Some crushed food, but the bag held despite the damage

      • This was your bag or something you heard about?

      • My bag, an S29 at Stony Brook Shelter. I was truly pleased at the bag’s toughness.

      • S29, an older white model which is what I mainly use myself, but not the current black Ursack Major.
        Did you he actually hole the bag or leave tooth indentations in it?
        Nice to have an actual eye witness account.

      • Some indentations but I counted 5 or 6 actual holes. He attacked it once about 9 at night and once about 5 the next morning.
        I saw the first one not the second so i don’t know if it tried a different approach. He quit before I could get up and get around the shelter. Hole in the link, hope it works, was big enough to slide a pencil through
        https://photos.app.goo.gl/Lht1EZieQM1rYqMc9

      • Hannover huh? I guess it’s time to upgrade to a black Ursack Major. That’s awful close to home in the Whites. The AT in Hannover is technically in the White Mountain National Forest. There’s a corridor all the way to Moosilauke.

      • Checked my map to get actual location. 37 miles south of downtown Hanover on the AT.

  2. I have owned a Ursack for quite a while along with the aluminum liner. At that time it was called S29 All White. For several years I used it in any areas that do not require a bear canister. After hanging it a few times like a traditional bear bag (performing the clown show), I started tying it to the trunks of trees which was the recommendation at the time. The first thing I stopped doing was using the aluminum liner. It seemed like a good idea, but it defeated some of the reason not to carry a hard canister, in that it took up basically the same pack space as the canister. I never had anything bother it all the time I used it, but the comment by Rex is sort of what I thought about the condition of the bag would be if it was ever attacked. Your comment on them absorbing water, is the main reason I quit using the Ursack all together. Several section hikes where it poured rain multiple nights made it miserable to pack the sack to hike each day. However it is good to see that if this is “your cup of tea” that Ursack now offers one that can handle bears and small animals both.

  3. I use an Ursak Major in bear country and so far have never had to deal with sliming of food, other than that caused by hungry intended recipients. Of course, my cooking prowess has also been known to cure hunger pangs on sight, even to the point emaciated ursidae might reconsider joining in.

    When section hiking the AT with my meticulous buddy, he did high quality hangs with his bear bag and hung my Ursak along with it, which kept bear mastication from happening. This also made the extra weight of the Ursak unnecessary. I may go to a lighter bag this autumn when we hike another hundred mile stretch together.

  4. I line my Ursack with an OPsak for added food protection, which also allows me to keep the OPsak inside my pack, and put a rain-soaked Ursack on the pack exterior.

      • what if you put a plastic bag on it after you tie it to a tree.

      • Grandpa will be trying out
        ZPacks 14L Dyneema Big Food sack at 1.5oz next section. Can still hang sacks together, and feel we have an improved method of bear hanging that won’t require searching for adequate trees.

    • Once again, great review. My wife and I used the Major last year on over 1800 miles of the AT and intend to use them for the remaining miles. They worked exactly as promised. We had no problems with critters or bears. We changed out our opsacks about 4 times at preset intervals of 400 miles. We also carried a spare odor bag which we placed the ursack in on rainy nights before hanging but the cord still got soaked but so was everything else so it wasn’t a great issue . We also had to use our spare odor bag a few times when our outa town
      load was too full. In those cases we filled a cheap sinylon bag with our “smellables” (trash, toothpaste etc.) and then hung. As
      we came north we saw few, very few in fact, who hung their food correctly and more who kept it in their tent or shelter with them. Another reason to avoid shelters, in our humble opinion! We did run into one
      Hiker who told us how these bags didn’t
      work but then when asked found out no opsack was used and it was stuffed into the
      middle of a dead stump, pretty favorite
      spot to insect forage for bears and critters.
      We did have people tell us the white ones
      looked “dirty”! To tell you the truth, dirty
      and hiking seem pretty inseparable so color wasn’t a great concern either and they did wash up a little bit, about as good as we did!

  5. I’ve had success hanging a large waterproof sack in northern Minnesota and when I end up sharing a site on the Superior Hiking Trail one of the first things I do is have the bear bag conversation and I offer to hang other people’s bag. This is for partially selfish reasons because I’ve seen some pretty pathetic attempts and I don’t want a bear around. Even in the areas with just small limbed Aspen and Fir it may take more time but can be done. A good tip I got this weekend is if you can’t find a good rock your water bottle will do for tossing the line.

  6. Philip, have critters ever compromised your ursack major?

    • Never. I think the most likely “critter” use case for the Ursack Minor and the AllMitey are bear boxes and lean-tos. My Ursack has never been compromised in either of those situations but that’s probably more a function of the box or the fact that I hang my food in Lean-tos

  7. From a functional perspective, I think they got this one backwards. Should have put the kevlar on the outside and the spectra on the inside. If a critter happens to nibble his way through the spectra only to be stopped by the kevlar, then worst case some bear wants a go at your bag somewhere down the road, he’s got a breach to work with and can most likely defeat the kevlar. I suppose one could replace the bag after any critter damage and play it safe, but it would make so much more sense to reverse those layers (unless perhaps UV exposure is more of a concern with the kevlar they are using?). I do wish someone would come along and perfect the Opsak bags. Thinking on the history of Ursack, I have often wondered if its original maker had been better at the engineering/design part of it and perhaps better with both marketing and communication, maybe those early repetitive failures could have been avoided and it might see wider acceptance. Still has its drawbacks compared to a canister no matter what, I guess. Hopefully the new owners can continue whatever evolution might remain for sacks.

    • OP sacks were perfected long ago for transporting organs such as kidneys. Double bagging in grizzly country is the way to go. Here in the SE USA, 3 wet years and ample food have given rise to increased bear population. Hungry bears are everywhere! Ursack is the way to go in the SE, though some areas, like Shining Rock NC, are looking at mandatory hard cans.

      Bill in Roswell

  8. Hubby made me an aluminum liner for my Ursack (not Almitey) from a cheap piece of aluminum he got from onlinemetals.com . Ursack has the specks on their website so you can buy the exact same thing. However you need to be able to cut the metal since the smallest dimension it comes in is 12″ wide and the Ursack I have needs 11.4″. You also need the skills to bend the aluminum as well. Hubby has all that under control, so I got a liner for like $12. Only use it in places where I think there is a real possibility of there being bear activity.

  9. Why not just sew only a Velcro closure on the inside of a Major just below the drawcord rather than basically sew the Minor, with its Velcro enclosure, into the inside of a Major? Seems to me that the double thickness created, with one bag inside another, is overkill and a big reason that the Almighty is considerably heavier than the Major or S29, which is what I have used for a good number of years. Thanks, Phil, for another great review!

    • I suspect it was a tactical move to appease some major retailer. It isn’t designed optimally but it does take the guesswork out of trying to figure out whether you need the major or the minor.

  10. Paul

    I have many years experience with a Bearikade canister in the Sierra and other ranges. Last summer my daughter and I hiked the Wind River High route and took the larger Ursacks. Compared to a good canister the Ursacks seemed really a pain in the neck. More hassle with packing, odor- proofing food, considering rain, and tying them up. We talked to another hiker who was carrying her canister and she agreed they were not worth the small amount of weight savings.
    The trick with hard canisters is to carry them on top and outside of your pack. You can use a smaller more compact pack that way and packing up is super easy. It works especially well with most of the roll top pack closures.

  11. Thanks for another helpful review and to the commentators as well for sharing your experiences! I’ve been hanging a light stuff sack with an OP for years and never had any problem with bears in Colorado, but want to keep it that way. I worry most about critters. The marmots in the areas I go are particularly curious and sometimes quite bold with my pack.

    An artful hang is very satisfying. I just nailed one on my last trip under a narrow-gauge train trestle! But structures humanly designed for hanging things is what I am generally trying to escape from. After some recent struggles, I’m about DONE with the forced hassle of hanging. Getting too old for this s&@t. Given all the trade-offs, I think I will start by experimenting with a borrowed canister, but I’m betting I end up with this bag and hang it as well as I can but without so much pressure.

  12. I have been using an Ursack with an Opsak for years and have never had any critter even go near it. I usually tie it about chest high around a 6inch diameter tree a little ways from my tent. Full disclosure , I have even kept it in my tent when I assumed I would be making breakfast in the vestibule (thunderstorms). Sure, the opsak is not perfect, but i doubt that you leave any more scent on it than you do the rest of your stuff. My opsaks usually last at least 6 months and usually longer

  13. I’ve used the bear-resistant ursacks on almost all of my hiking/packrafting trips in Alaska during the last decade, always in black, grizzly, and even polar bear country. These unsupported treks are last at least 2 weeks with the nearest village sometimes up to 100 miles away, and carrying two hard canisters for sufficient food is just not practical. In the forest I’ll tie the ursacks to a tree trunk, but in alpine or north of the timberline the only option is to hide them among rocks or dwarf willows. I also use Opsacks mainly to keep the contents dry; after a few days of use they are not really odor proof anymore. Surprisingly, after all these years the ursacks have never been disturbed by a bear, at least not that I could tell. This could be attributed to the wild nature of the bears up here, as opposed to the often humanized and delinquent ones down south.

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