SAF-WAT

The SAF-WAT was a small, bi-metal disk (two types of metal fused together) that was sort of snapped, or tensed, prior to being placed in water, and when the water reached pasteurization temperatures the two metals expanded at different rates, causing the disk to snap back to the original shape. Solar Cookers International had to discontinue that product because in certain types of water, over time, a bit of corrosion would occur, causing the SAF-WAT to lose its ability to snap properly. These were also quite cheap, simple devices.
==See also==
*Water Pasteurization Indicator
Category:Water pasteurization