Q: Does sealing food and sinking it in a lake or river create an odor barrier that will prevent you from finding and partaking of my food? —John, via email
A: If you've got reliable waterproof bags on you when you go camping, the combination of plastic and submerging your food underwater will create an odor barrier that should keep me from narfing on your vittles. Several layers of plastic bags are key, though: Contrary to popular belief, a single plastic bag is slightly odor-permeable, so you should use more than one to back it up. Between the several layers of plastic and the lake or river water, I probably won't be able to sniff out your Lucky Charms.
But there's one element that keeps this from being a foolproof technique: Submerging your food in a lake or river will do nothing to keep me fromseeing your stores of snacky goodness. Since I regularly prowl riverbanks and lake shores for fish, carrion, and other natural goodies, I'd stand a decent chance of getting curious about your underwater foodbag. Remember, I can spot fish cruising by in dark, rushing water well enough to catch them in my mouth mid-air, so don't think I won't notice your Oreos bobbing just below the surface. Are you willing to take that chance?
To be 100-percent safe, you'd have to paddle out to the middle of a large lake, weight and submerge your cache, and attach a buoy so you could find it. That's not going to be fun when oatmeal time comes the following morning, so given all the hassle involved, you're probably better off using a bear canister and shoving it into a deep rock crevice or atop a large boulder (we're crappy rock climbers) far from camp.
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