Can Bear Spray Expire?

Hey, that stuff is expensive!

growling grizzly bear
Grambo Photography/All Canada Photos/Getty Images

You may have noticed that your can of bear spray has an expiration date printed on it. How seriously should you take those little numbers?

Bottom line: Your bear spray won't magically go from full power to zero power the minute its expiration date arrives, but all aerosols do lose power over time. Your bear spray might work to some degree once it's past the expiration date -- but why would you want to introduce an extra element of risk or uncertainty into dealing with bears?

So do yourself a favor and pay attention to that expiration date. And keep in mind that your bear spray's performance can be affected by how you store it, too. Extremes of heat and cold will reduce itself performance, and extreme heat (say, being stored in a hot car) may even cause the pressurized contents to explode. How's that for an unpleasant scenario?

But Bear Mace Is Expensive!

At around $50 (or more) per can, bear spray can seem pricey. But that works out to just $10 to $15 per year over the life of each canister -- a lot cheaper than a post-mauling hospital stay.

But What If an Expired Can of Bear Spray Is All I Have?

If an expired can of bear spray is all you have, I say take it! There's no guarantee that it'll work, but some chance is better than none -- and every expert I've ever talked to agrees that just having the can of bear spray in your hand can give you the courage to do the right thing when a bear charges: Stand your ground.

What to Do If You're Carrying Bear Mace

With that in mind, here are a few things to keep in mind if you're carrying bear spray:

  • Bear spray only works if you can get to it immediately, so don't carry it buried in your pack!
  • Pay attention to wind direction. If the bear is coming from upwind (with the wind blowing from it toward you), try to maneuver so you can fire the spray crosswind. You'll get less of the bear spray in your own face.
  • Bear spray is loud when it fires! Most manufacturers offer inert practice cans, or you can get a chance to fire off a practice can in bear defense classes and many public lands events (like National Trails Day).
  • Bear spray is a deterrent because when airborne, it burns the bear's mucus membranes. Think of it like super-powered mace. But once the spray settles, it's just seasoning. If you had to use bear spray in or near your camp, that's just one of several reasons to pack up and move if you can.