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How Safe Is Your Food? Investigating the effectiveness of odor-proof bags
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Daniel Fish

Locale: PDX
... on 04/17/2013 07:32:37 MDT Print View


Edited by on 06/09/2013 09:25:20 MDT.

Clayton Mauritzen
(GlacierRambler) - F

Locale: NW Montana
Re: Thanks for the recent comments on 04/17/2013 16:43:43 MDT Print View

Daniel, it's an excellent one--the gold standard for the issue. FWIW, I also found the author very easy to interact with. I emailed him about a question I had regarding his research, and he replied back within a day or so.

Gary Dunckel
(Zia-Grill-Guy) - MLife

Locale: Boulder
Herrero's book on 04/17/2013 16:54:27 MDT Print View

Daniel, I concur with Clayton's opinion. Steven Herrero is probably the most preeminent expert on the griz. His studies seem very scientific and well designed. Also, his writing is quite readable. For further info about the brown bear, check out the Craighead family. They were pioneering griz studies in Yellowstone (and Glacier) back in the 60s-70s. They were also scholars, being based at the University of Montana. They have been a bit controversial, but they did a good deal of valid research. There are numerous books about the griz, but Herrero and the Craigheads pretty much stick to science, with little anecdotal conjecture thrown in.

Edited by Zia-Grill-Guy on 04/17/2013 17:50:40 MDT.

Ian Clark
(chindits) - MLife

Locale: Cntrl ROMO
Great read on 04/18/2013 00:03:55 MDT Print View

I enjoyed your article and I appreciate the time and effort you put in to the project. I don't enjoy bear encounters when I am in camp. Even a cat circling my camp at night can get me a little edgy. I think I have been lucky, but not all have been so lucky and this is in a state with no Grizz. Just because someone did not die in their tent from injuries from a black bear encounter and make Wikipedia does not allow me to take the critters for granted. Congratulations on generating a flurry of comments and I look forward to reading more of your articles.

Jennifer Mitol
(Jenmitol) - M

Locale: In my dreams....
Odor lessenining?? on 04/18/2013 07:29:41 MDT Print View

It may not prevent a bear from getting my food, but wow they do a great job of keeping ME from smelling the hot n spicy cheez its in my entire pack and on all my gear.

aluminum foil on 04/18/2013 17:52:31 MDT Print View

Lots of food and other items seem to be supplied in packaging with aluminum foil liner as well. I have always figured that cut down on permeation.


I made the mistake once, and only once, of putting a bit of toothpaste in a tiny ziplock.
Everything in my pack smelled like toothpaste, like the ziplock wasnt even there. It was horrible. I can say, ziplocks are super duper permeable by comparison.

peter vacco

Locale: no. california
Re: How Safe Is Your Food? Investigating the effectiveness of odor-proof bags on 04/20/2013 19:52:20 MDT Print View

nice article.

it has been my experience that peanuts will stink directly thru a ziplock, but cashews and almonds will not display anything like that sort of thing.

tide laundry detergent will also go right thru its bag, and into MY food.
the stuff from trader joe's does not do that nearly as much.

story :
once upon a time outside of jasper alberta i chanced to buy a whole large packet of pepperoni, which i soon opened and rebagged. it was Good and Hot pepperoni, and once opened you could smell it not only outside it;s bag, but outside the pack !
omg... so .. i ate it.
ALL of it.

it burned going down. and it burned going out.
yee haw !


Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: How Safe Is Your Food? Investigating the effectiveness of odor-proof bags on 04/21/2013 00:44:14 MDT Print View

Here in Oz it used to be traditional - like dead normal, that all gear smelt of sausage. Instant tribal ID.


Texas Chinooks

Locale: DFW
Re: Re: Odor Proof helps but isn't a comprehensive bear strategy on 05/08/2013 18:44:02 MDT Print View

Well, I guess I'll use a bear canister so I don't train the bear but honestly I probably smell like everything that I'm storing. I brush my teeth with smelly toothpaste, I probably wipe my hands on my pants or food smell is transferred to my walking sticks, the wrapper to my Pro-Bar is in my pocket until I stop for dinner and put it in the trashbag in my bearikade, the steam of my cooking meatloaf is probably in my wool shirt.

Michael Ray
(topshot) - MLife

Locale: Midwest
Impressive K9 on 05/17/2013 20:39:51 MDT Print View

This local story reminded me of your testing. I wonder if it's really smell they use for phones or (ultrasonic) sound? To smell it while inside a ziploc under water is quite a feat.

Curtis B.
(rutilate) - MLife

Locale: Pacific Northwest
Great article! on 08/07/2013 20:16:01 MDT Print View

I know I'm playing necromancer in reviving an old thread, but this was some might good research work!!

David Erikson
( - M
A different opinion on 08/18/2013 13:21:19 MDT Print View

I've used OP sacks for the last 10 years (at least) in the Sierra Nevada backcountry on annual trips. They were used in conjunction with an Ursack as final protection. On at least 4 occasions when bears were IN OUR Group's CAMPSITE the bears failed to detect the food I had; my food was taken by me as a supplement to the group's food. The latter was stored in aluminum panniers ("bear boxes" if you will) used now by all mulepackers in the Sierras. So it might have distracted the bears from detecting my food, since there was no attempt to conceal the contained food's odors, as I did with the OP Sacks. On many other occasions there was no evidence or knowledge of a bear's presence during the night, but we were in areas notorious for bears along the John Muir Trail, such as at or near Thousand Island Lake, Lake Ediza, Glen Aulin, (and ALL other sites on the Yosemite High Sierra Camp Loop), Rock Creek (Cottonwood Pass region), Cottonwood Lakes, Rae Lakes, Paradise Valley and other sites on the Rae Lakes Loop (this included one of the episodes of a bear in camp attacking the aluminum bear boxes but ignoring my stash) or East Lake. Indeed, I've not had my stash moved at all suggesting a bear had tried to get the food but gave up. I might add that my food was always some distance away from the aluminum boxes containing the group's food, which I would think would lessen the "distraction" factor sited above.
So the bears ain't got my food yet.
David E.

Luke Schmidt
(Cameron) - MLife

Locale: The WOODS
Re A different Opinion on 08/18/2013 14:19:41 MDT Print View

I definitely felt like my Opsack did a better job of containing food odor then regular ziplocks. It made me feel a lot better in grizzly country.

I've read that bears actually have pretty good eye sight so I work under the assumption that if the bear is close enough to see my bear bag he'll probably investigate whether he can small it or not. I try to rig my bear bag in a place that is not super visible. In the feature I'll probably take a stuff sack for my bear bag that is either camo or a low visibility color like brown or gray. I don't want an orange sack that sticks out like a sore thumb.

My theory is that an Opsack is better then nothing especially if a bear is a couple hundred yards away and he hasn't seen my food bag or my shelter.

David Erikson
( - M
"odorproof" OP Sacks vs black bears on 09/04/2013 16:11:55 MDT Print View

As a follow-up to my posting above: I just spent 4 consequtive weeks in the Sierra Nevada backcountry with my OP sacks concealing my food against bears and other wildlife. Nary a nibble; on the other hand, there was no evidence of bears being in the vicinity, or at least no obvious bear attempts on our camp food which was stored in aluminum bear boxes carried by mules. Also, the frequent presence of mules may well have kept ursines away.
David E.

Trace Richardson
(tracedef) - MLife

Locale: Southern California
Second Study on 02/16/2014 08:18:50 MST Print View

Anyone know if the second study that Ike mentioned ever occurred?

Ike Jutkowitz
(Ike) - M

Locale: Central Michigan
Re on 02/16/2014 12:44:17 MST Print View

Sorry Trace. Dealing with some personal stuff at the moment. It's on the back burner for now, but I'll keep you posted.

Wayne Koepp
(arky82) - M

Locale: Northwest Arkansas
How Safe Is Your Food on 08/13/2015 08:34:24 MDT Print View

I would think that masking the odors would be more effective than trying to contain them. You could try something like powdered sulphur or spray a Ursack with OdoBan Bitter Barrier. I know our cat takes one lick of the Bitter Barrier and never returns.

Anthony Britner
(ant89) - F

Locale: North Wales, UK
Scent proof? on 08/16/2015 09:07:59 MDT Print View

Plastics are actually porous to scent particles so they can escape by being absorbed into the plastic and then released on the other side the longer the scent is in the plastic container the more scent diffuses though.

However metal containers are not porous so scent particles cannot diffuse through it can only excape at the joins/ openings.

Thickness of material comes into the equation. The thicker the material and/ or the more layers there are then the longer it takes for the scent to diffuse into the outside air.

It may be possible to mask the scent of the food by including a very strong smelling, potentially displeasing substance in one of the outer layers.

Mitchell Ebbott
(mebbott) - M

Locale: SoCal
Closure Type on 08/16/2015 21:02:08 MDT Print View

I'd love to see a test that includes Nylofume/Nylobarrier bags, or even the BaseCamp bags that you can get at Amazon or WalMart. These bags are made to be closed with the twist, fold, and twist-tie method, and that seems a lot more secure and odorproof than the zip on the OPSack.

Jennifer Mitol
(Jenmitol) - M

Locale: In my dreams....
then why don't drug smugglers use them? on 08/18/2015 17:15:18 MDT Print View

I mean, if there truly were a plastic ziploc bag that masked odors from dogs (which are way less blessed in the olfactory department) why in the world wouldn't they be the hit of the drug smuggling community?

That's all I have to say.