Trace metals would be the culprit based on what I know. Do you test your water regularly? It’s really the only thing I can think of.
I got a pinkish tint once or twice. I use distilled water doctored up with Bru’n water.
Interacting with vessel metals maybe? I wonder how many people are passivating their vessels.
Once a year. Never a sign of trace metals.
I heat my water in an AL kettle. I do nothing to passivate it, but it does have a thick oxide layer. Not to mention that I use it every time.
I’m stumped then!
It’s the BTB precipitating out something. Typically you’d think of iron or traced metals because common sense and the literature points to that. Since you said you see it before grains added, you can rule out grain contribution. The only thing left would be reacting with the vessel.
Not sure man. I’ve never experienced the purple so I can’t add anything other than saying for people who experience it to compare and contrast and see where there is overlap.
I’m stumped, too, but in reality it doesn’t matter. The beer turns out the same either way. And it’s not always purple…sometimes greenish. But I consider it a curiosity rather than a problem.
They say that gallotannins (active ingredient in Brewtan) are mixed with iron to create black or blue ink. The slight color that we see in Brewtan treated water is consistent with that coloration. Its just that its much more dilute.
Right, “iron gall ink” was the main ink from at least the middle ages until the 20th century. It starts bluish-black, but you’ve no doubt seen pictures of old documents where it is fading to reddish brown. Apparently that range of colors is natural to the complex, and it seems to fit the range of descriptions of water here.
The information says that it works through adsorption and precipitation, leaving the proteins behind with the spent grains in the mash. Would that work equally well with BIAB?