« on: November 17, 2016, 08:03:43 AM »
I had theorized (on Brews-Bros) that iron was most likely causing the green color. Later the guy must have run some water tests (? he never did state the source of his definitive conclusion?) and confirmed that it was in fact iron causing the green color. If this occurs with anyone else, consider whether you've ever detected any metallic taste in your water or beer. And even if you haven't, be glad that the Brewtan is in fact removing the iron from the water. The green stuff will eventually settle out and not stay in the beer. SO... the green color is harmless.
A similar effect is theorized for copper, except for copper the color expected would be a khaki tan color. And other metals may cause other more interesting colors. In any case, the net effect is that these metals are being removed from the beer, which should result in a cleaner tasting beer.
The alternative, of course, is to start from distilled or RO, and then you'll never see this weird coloration, except perhaps for the pink color reported by some. I wonder if this might be just from impurities in the Brewtan itself, which seems it may be made from sumac fruit, which is red. Now I'm pretty far out on a limb, but I do wonder.