Originally Posted by ArcLight
Define "thin". It means different things in different contexts.
For traditional mashing, 2- may be considered thin.
For BIAB I am wondering if 3-1 is ok. 4-1?
For "thin" BIAB mashes, call it 4-1, I think you need to mash longer, and ad lower temperatures. I think a 4-1 thickness (thinness) at 156 would not work as well, due to the Beta Amylase being denatured.
The only problem with grinding too fine is you may end up with flour (and husk bits) in your ferementor.
The husks normally shred but remain quite long and stringy. They rarely get out of my bag during the brew. I do notice a bit more trub than if I don't re-grind, but an improvement in efficiency of 15% or better more than makes up for it. I was having a hard time getting my numbers up until I started crushing the crap out of it, and I haven't really noticed enough trub to worry about it. The Irish Moss or whirl-floc seems to firm it up and drop it to the bottom of the kettle during cold-break and I can leave it behind in the kettle.