Originally Posted by seanppp
I always like posts that start with "um". Thanks for that.
I was thinking it had more to do with agitation.
Um, Glad I could I could make your day
From what I've read here, tannins are extracted by pH and pressure. Real pressure. Like hundreds of lbs of grain pressure. The amount of pressure from squeezing your bag won't cause any issues. Even boiling temps don't matter if the pH is in range.
Agitation doesn't seem to be an issue. It's commonly recommended to stir like mad at several points in the mashing process.
Fly sparging can have tannin issues, I think (I batch sparge), but again, that's pH.