[Lmorgan]

IamZeke is right about redundancy (and hands-on knowledge) being good things to have in times of trouble.

So, going back to the initial question about distillation, having a TEOTWAWKI still is a very, VERY good idea.

You can use a still to make pure water not only for drinking but for medical uses. You can make alcohol for drinking, fuel, medical uses--and barter the same.

Need an after-the-crash business? Make booze for people using their firewood and corn for, say, 10% of the ingredients. Or 10% of the product.

I don't know of anybody making alcohol (for any use) with a passive solar still.

In any case, a huge still is a large investment in time and money. And not very portable.

But a small still, something that can make 1/2 gallon an hour of almost pure alcohol, is much less expensive and actually very easy to build as a DIY project.

That same small still would probably put out 10 gals an hour of pure water--which is not too shabby for a stove-top still.

I recommend the 2" Bokakob Slant Plate Still, which can be found at
http://wiki.homedistiller.org/Boka_Reflux_Still_-_How_To_Build

I note in passing that owning and running a still is not illegal in most places--as long as you aren't making moonshine. You can get a small volume license from the Feds if you want to make your own alcohol fuel, for example.