Ok, here’s a scenario that seems a bit odd but it actually happens more often than you’d think. You’re out hiking and you lose your way. You are pretty well prepared for a day hike. You have the right clothes, something to make a fire with and a few snacks. And you also are near a lake and a couple of creeks so you do have water.
But you have a plastic Nalgene water bottle and it’s got about an inch of water left. How in the heck are you going to make sure you don’t get a parasite by drinking out of the lake or creek? You know that water is the second most important element of any survival situation. You also know that to purify water, the best thing you can do is to boil it. How are you going to do it?
Placing hot rocks in water is an ancient technique to purify water. If you get stuck without a metal container to put on the fire, there are ways to boil water if you’re willing to get creative. The first thing you need is a container that will hold water.
If you have a ton of time to kill, you can fire burn a log and keep scraping the coal out until it’s dished out enough to hold water. The only problem is that it will probably take all day. So, if you would rather avoid all that work, start looking around. Sometimes you may actually find a hollow log. Or, if you’re around a river, sometimes there are natural depressions in surrounding rocks.
Another cool way to make a container is to dig a hole and line it with something waterproof, or sort of waterproof. Do you have a small tarp? What about a space blanket, a windbreaker, a plastic bag, your backpack, or my favorite — your hat.
The reality is that you probably have something to line the hole you dug that will hold water long enough to boil it. The next step is to get a fire going and place about a half-dozen rocks in it to heat up. Be very careful to use dry rocks! Wet rocks, even dry-looking rocks near water may be dangerous when heated up. They explode and send shrapnel flying all over the place. Trust me, it hurts! Look for porous or volcanic rocks. Just make sure they haven’t been soaked in water.
If you are using a tarp, or any kind of plastic, place some rocks on the bottom so the hot rocks don’t touch it. You’d be surprised to know that water is such a great conductor of heat that the plastic etc. rarely gets hot enough to melt, even when the water is boiling.
Next, fill up the lined hole with water and carefully place the rocks you heated up, in the hole, one by one. You can make some fire tongs with green wood (willow etc.) to transfer the rocks.
Keep adding rocks until you achieve a rolling boil. The water will be dirty, but it will be safe to drink. You can use a handkerchief or your T-shirt to strain the water back into your Nalgene bottle.
Some experts say to boil the water for five minutes up to 20 minutes but the truth is that all you have to do is achieve a boil and your water is safe to drink. I’ve never been sick and I’ve boiled a lot of water in my life. You now have a method of purifying water that will work over and over.
I have made containers out of bark as well. If you are in an area where you have birch, aspen or any other thin bark, you can cut and peel it off the tree. Soak the bark so it’s pliable and make a container by bending the sides up. Bark makes an excellent container that you can take with you and it can be used over and over to drop hot rocks in. You can also make some pretty good broths and stews in them.
If you use your awareness skills well, you will find that nature provides everything you need. Get out there and try it sometime.