What Is This?

I'm getting ready to hike the Pacific Crest Trail next week and being a drought year, water is a big concern. We have an emergency item for our packs if we run out of water, but we have no idea what this item actually is.

I'm hiking an 80 mile section of the Pacific Crest Trail starting next Friday and our entire trip is planned around water sources. With this heat and the drought, there are going to be some 15 mile days to make sure we get to the next water source. One of the girls in my group picked these Emergency Waters up for each of us. The only problem is we have no idea what is actually inside the pouch.

Obviously I understand that I should only drink this if it's an emergency such as being sick, injured or in a desert. But my question is, once I open this pouch and put it to my mouth, what am I pouring down my throat? I even went online to look and still got no description on the contents. I did find out it's good for 5 years!