WAPI – Skip boiling and make water safe with less fuel

I was watching a video on water treatment and came across something I had never seen mentioned. It’s an indicator that shows when the water is safely pasteurized without the need to bring it to a full boil. It’s tiny, light, and will save a ton of fuel. It would really extend the fuel in a BOB and still be useful to have around even in a bug in situation.

Link to the video with the explanation (the whole series is worth watching): https://youtu.be/rIMeq0c7rJM?t=877

Product link: https://www.amazon.com/dp/B00F7104EY/


  • Comments (8)

    • 2

      I love people who do experiments like this. I just watched the video and by using a WAPI and pasteurizing the water vs getting it to a roaring boil, you use half the fuel. For his pot and stove, his 110 g fuel canister can get 22 pasteurizations on a lot heat setting vs 11 roaring boils on high heat.

    • 3

      You also might be interested in the Kelly Kettle. They’ve been around a long time, originally from Ireland. We have all the sizes, over the years. It’s like a tea kettle with a fire, inside. Saves sooo much time and fuel. And the whistle stopper lets you know the second the water is boiling. We use all the sizes depending on what we’re doing (car / basecamp camping or hiking or day tripping).


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      • 1

        I have wanted a Kelly Kettle for years because I’ve seen the potential they have of being super efficient and the ability they have to boil water with only using twigs.

        How are they to clean, both the fire chamber and the water chamber? Are they durable and sturdy? What size do you find yourself using most often?

      • 2

        Bradical, I just realized that I forgot to reply to you. Sorry about that.

        Cleaning the outside & fire chamber:  I just use a scotch brite pad to do the fire chamber after the trip is over. No biggie. Burning pine needles and pine twigs does seem to produce more sticky stuff, so if that’s not the only choice of fuel, it’s better to do other twigs.

        Cleaning the water chamber:  Haha haha, I don’t think I ever cleaned it with my first model. When they came out with stainless steel, I upgraded to that. Like a teapot, I will occasionally descale the inside using vinegar & water. We have hard water, here.  One thing to know is to only put WATER in the water chamber to heat up. (i.e. don’t put like soup in there or anything)

        All the KKs are extremely durable. I mean, i wouldn’t run over one with a semi truck, but I’ve had no issues with any of mine over the 13 years I’ve been using them.

        As far as which size we use most, well, it just depends on the activity.  Solo day hike? Trekker. The two of us backpack hiking? Scout. Camping with our big tent as a base camp? Well, then it’s the Base Camp, which is the biggest and holds the most water.

        KK is also a wonderful company to work with. You can buy replacements to everything, too, if you lose something or mistreat it.

      • 2

        Wow that’s pretty cool.

    • 4

      This device probably makes the most sense for people trying to use a solar oven to kill pathogens in (pasteurize) their water. That was the original purpose for the WAPI. See http://solarcooking.org/pasteurization/metcalf.htm for more on the science and history.

      If you use the device in a pot over a flame, try not to let the plastic touch the metal of the pot’s heating surface so the WAPI doesn’t melt. This is not as much of an issue in a solar cooker because the temperatures don’t get as high as when you have a flame.

    • 2

      Thanks for sharing, this was cool to see!

    • 2

      The WAPI would save even more fuel by not even heating it to simmering, but I just want to point out that if you know what a “simmer” looks and sounds like, there’s no need to heat water the additional 30 degrees or so to a full boil.  It’s pasteurized well before it reaches the simmering point at around 180 degrees F.  If you have an accurate candy thermometer, you can easily test this on your stove top.