How to Boil Water in a Plastic Bottle

Be on the lookout for a plastic bottle when you're hiking. It doesn't matter what brand of soft drink; a regular pop bottle works just fine. Stick it in your pack or pocket for later use. The old saying "one man's trash is another man's treasure" is true---especially on the trail.

Gather some small sticks and build a fire when it's time to camp or eat, or light up that can of Sterno you brought for just such an occasion. Either way, you're going to need a heat source for boiling water. Make sure you have a tree nearby to run your string or vine up for hanging your plastic bottle over the fire.

Fill the bottle about three-quarters full of water. It can be most any water found in a creek or pond, as you will be boiling it to remove any germs and make it safe for drinking. Tie the string or vine around the neck of the bottle, and run it up over a limb and back down so you can tie it off and adjust the height of the bottle over the fire. Start warming the water 6 inches or so above the heat. Put your hand under the bottle to feel the temperature. It should be just hot enough so you have to move your hand but not too hot. You have to start slowly.

Keep the fire about 6 inches below the bottom of the bottle by adding small sticks. Do not let the fire get high enough to touch the bottle. At this point, the bottle will start discoloring, and a small drip may show up on the bottom, but don't worry about it. The bottle may even start to swell and look baglike on the bottom, but it's natural for this to happen.

The fire will start to get white and hot at this point if done correctly, and you can let the bottle down until it is just off the coals by an inch or two. Small bubbles will start to rise, and it will be just a few minutes before you have a full boil. If the water is just slowly bubbling and will not boil, build the fire up on the sides with very small sticks to adjust the heat. If you are using Sterno or another heat source, just turn up the heat until you get the boil you desire. After the water boils for a short time, you can raise the string and let it cool. The water when cooled will now be safer to drink.