Buying dried root vs dried root bark.
In 1998 I went to the SWSBM in Arizona, USA, and while in 'merca, I bought herbs from Blessed Herbs, then a very reputable bulk herb house, now unfortunately on the purge/puke/parasite-cleanse bandwagon.
From Blessed Herbs I got bright yellow berberis (Berberis vulgaris) root, which made a dark yellow berberis tincture. Very good quality, in other words.
Back home in Finland I bought my berberis root from the UK; the UK and Finland are both in the EU, so there's no import duties. In addition, if I give sellers my EU VAT # I don't have to pay VAT. In other words, I get bulk herbs cheaper from the UK than from the US.
Most batches from UK bulk herb houses were as good as the American herb, but I just shook my head at one batch: this they sell as quality herb? OK, it was called "berberis root bark", so it should actually contain root bark, but it looked more like bottom-of-the-barrel brown leftovers and not like the yellow berberis that I'd learnt to appreciate.
Oh well, I used other batches of berberis, leaving this one in the cupboard in case I'd run out of quality herb.
Now I've run out of quality herb, and I've run out of berberis tincture, so I've made a new batch from the brown-barked stuff.
By percolation, at 1:5 50%, same as my old tincture.
There's a difference.
Pic: Berberis vulgaris: two qualities of dried herb and tincture.
Dried herb and tincture, side by side. The yellow one is quality herb, the brown one - isn't.
Note, both of these are Berberis vulgaris, common barberry. I expect the brown stuff will work, but it's not as good as the yellow stuff.
Berberis is a very simple herb. Its action is due to one single constituent, berberine, which is yellow - very yellow. The tincture will stain everything it touches.
Most herbs are far more complex, and with most other herbs you won't be able to tell quality from color. With berberis you can. (You can also tell the quality of Hypericum (St. John's wort) oil or tincture by its color.)