I was always paranoid about my starter dying or mutating.. every year or so I dry some and save in the freezer in case I need it. 

I have 6 years worth of starter.

Last month I did something really stupid and killed my starter.  

To give a starter a good start after feeding, I sometime put it in the oven with the light on until it bubbles nicely.

and of course I forgot about it, and turned on the over to preheat to 500f.  when I realized what I did it was too late and teh starter was coocked, literally.

So I dug out a dry 2006 version and in 2 days I had starter again.

Here is how I dry.  I make a wet starter, and let it go to nice fermentation, and then I spread ti on 2 pan with Silpat, and let it dry for 2 days.. 

once dry, I crumble it, and put it in in a zip-lock bag, in the freezer.