For many years, we have been told to boil water that may be contaminated by bacteria. Some groups have given different lengths of time that the water should be boiled. I have heard times of up to twenty minutes. Now none of this is bad advice, but it is not the best. Boiling water when it is unnecessary is a waste of fuel.
When you are boiing water you are raising the temperature to 212° F, but pasteurization only requires you to raise the temperature above 149° F. This will make a significant difference in fuel usage.
Pasteurization is quite simple. Just heat the water to just over 149° F and maintain that temperature for at least one minute. The water is considered pasteurized and safe to drink. Dr. Bob Metcalf, an emeritus professor in microbiology at California State University at Sacramento has been able to confirm this and has been involved in utilizing this technique in third world countries. This has also been confirmed by the CDC.
So if it only takes 150° F to make the water drinkable why do so many government agencies still tell you to boil water? One reason is that it takes time to educate people, including government officials to new developments. The second is that when you are boiling water, you get a visual indicator that the water has reached 212° F.
So how do you know that the water has reach a sufficient temperature to be pasteurized. One simple inexpensive method is to use a WAPI. This will tell you when your water has reached the correct temperature. It is small can fit in your pocket and is reusable thousands of times. A second idea is to have a cheap candy thermometer in your supplies.
I have been asked the question, why does it matter; it is easy to just heat the water to a boil. The reason is it takes a lot less fuel to heat water to 150° F than it does to reach 212° F. This can result in reducing your fuel consumption significantly.
Pasteurizing or boiling water is not appropriate when chemical contamination is present. This may increase your exposure to chemicals such as nitrates and solvents by concentrating them in the boiled water.
In a real emergency knowing how to pasteurize instead of boiling water may make the difference as to whether you run out of fuel.