The WAPI - Water Pasteurization Indicator. This is an extremely useful, pocket sized, resuable device that should be in every campers kit and every home emergency kit. It is just 1.5 inches long and about the diameter of a pencil, and weighs about 5 grams.
Disease-causing micro organisms in water are killed by exposure to heat in a process known as pasteurization. Water heated to 65 C (149 F) for a short period of time is free from microbes, including E. coli, Rotaviruses, Giardia and the Hepatitis A virus. (Milk and other Foods require 71 C (160 F) )
This is an effective way to get safe drinking water withou boiling.
Reference Temperatures: :
Worms, Protozoa cysts (Giardia, Cryptosporidium, Entamoeba) are killed rapidly at 55°C (131°F)
Bacteria (V. cholerae, E. coli, Shigella, Salmonella typhi), and Rotavirus are killed rapidly at 60°C (140°F)
Hepatitis A virus is killed rapidly at 65°C (149°F)
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That's right - you don't have to bring water to a roiling boil to make it safe. This can be useful in emergency situations, when fuel is scarce, or in sensitive wilderness areas when fires are not permitted.
The reusable, durable WAPI is a simple device containing a special soy wax that helps users determine when water has reached and exceeded pasteurization temperatures. The WAPI can be used for pasteurizing over most fuel sources — including wood, charcoal and gas — but it works particularly well in conjunction with a solar cooker. Great for camping and emergencies.
To Use (solar mode):
1.) Pour water into a black pot, jar or vessel
2.) Slide Wapi into Pot using the washer and string to orient WAX in the UP position. Make sure WAPI is in the deepest part of the CENTER of the pot.
3.) Put Pot in your Solar Cooker as you would for cooking (facing Easterly in the AM and West in the PM) - reorient as needed.
4.) Let it Warm the water - generally 1 hour per liter of water
5.) When the WAPI Wax melts and falls to the bottom of the indicator, pasteurization has occured. Even if the water has re-cooled - if the indicator has fallen to the bottom, pasteurization has occured.
6.) Let water cool before drinking. Keep water covered until use to preven recontamination, Don't let fingers or unclean object touch clean water. If you are unsure, re-pasteurize the water
You can also use this with water heated by a campfire or camp stove, just use caution to suspend the WAPI so it does not touch the bottom of the pot , and make sure the fishing line does not melt (suspend on a fork or pot handle). Remember you can use lower burner settings on stoves as water does not need to boil.
Note: Pasteurization does not remove dangerous chemicals, like arsenic. Pasteurization is not the same as sterilization - a process whereby everything, including heat resistant spores, is killed. The heat resistant spores that survive pasteurization are harmless to drink. Where sterilized liquids are needed - in hospitals and in certain food canning processes, for example - high temperatures above the boiling point are achieved using special pressure cookers.
