Dried yellow dock.
Airdried vs. dehydrator-dried yellow dock root.
The color of yellow dock root (Rumex crispus and other taprooted species) tells you how good it is. Root dug on a watery meadow can be almost white, in which case it's just yet another astringent - and the world's full of astringents.
Root dug where the plant has been struggling to survive, in sandy hills and similar, can be so yellow inside that the center of the root is bright orange.
That's the best root.
When you airdry yellow dock root it'll turn a dark brown, no matter what color it was to start with.
If you dry the root in a dehydrator it'll stay more or less yellow.
If you plan to airdry your yellow dock roots you should discard lesser roots right away, because you won't be able to tell later on that this was a lesser crop.
If you plan to dry your yellow dock roots in a dehydrator you can keep less yellow roots; they're still good, they're just not as good as they could be.
I use yellow dock root in teas for a "cool" liver, to heat things up. When I dig the root I discard white and light yellow ones right off. And I don't go digging for yellow dock in watery meadows, preferring spots where I know I'll get top-quality root.