Mississippi...
I have never stored any for selling the next year, but I do keep several nice roots after drying for my own personal consumption thru the year.
After they are good and dry I just pick out the ones I want to keep (I prefer small roots with lots of root hair and 20+ years age)... I just put them in a paper bag and fold the top down and put a rubber band around it.
When I finish eating one, I open the bag up and pick out the next one I want to eat.
I keep that bag right here in my home office - air conditioned, heat, low humidity, you know normal inside home conditions and I can't tell any difference in it (appearance wise) a year later.
It still looks just like it did after drying.
I have heard that it may lose a little more weight over time, but have never tested that myself.
If I happen to keep more roots than I eat in a year, when I sell the next years crop I will sell those year old keepers, and then keep back some from the current years batch to eat the next year.
I can't tell a bit of difference between the year old dry roots and the ones I kept and dried from the current years crop.
I think the main thing would be keeping them at normal room temps, low humidity and making sure no critters (bugs, mice, etc) get to them and eat em.
Below is a pic of a few of my eaters that have been dry for for almost a year now, just sitting in a paper bag in my home office.
Good Luck !
TNhunter