Higher temperature? I have squeezed the bag during BIAB pretty aggressively and haven't extracted any tannins (that I can perceive).

1 Answer 1


It's a misconception. You certainly can squeeze the grain bag you use for steeping. Tannin extraction is mainly dependent on pH, so if your pH is OK there shouldn't be a problem. Keep in mind that grain will drop the pH of your water, but of you use too much water for steeping the grain won't be able to drop it enough and you may get tannins.

  • I believe traditional BIAB uses a fairly large ration of water to grain, basically the total volume of the mash AND sparge together, so the pH of a BIAB mash would be higher than the same grainbill in a normal mash, I think? I wonder if there's something else going on chemically in BIAB that's preventing tannin extraction.
    – GHP
    Commented Nov 12, 2012 at 13:16
  • I don't know what it could be. I do know several BIAB people who make water adjustments, though. That would be the best way to approach it. And pH is more of an issue for some beer styles and water profiles than others. Given something like a pale ale and a not too extreme water profile, there may be no issue at all.
    – Denny Conn
    Commented Nov 13, 2012 at 23:43
  • I've never noticed a difference in terms of water volume doing BIAB, so I doubt it affects pH much. Squeeze away!
    – bk0
    Commented Nov 17, 2012 at 4:49
  • It definitely can affect it. It depends on your water and your recipe. Try measuring it both ways.
    – Denny Conn
    Commented Nov 17, 2012 at 17:06
  • @bk0, the 'original' BIAB process specifically calls for combining your mash and sparge volumes into a single infusion mash, often at fairly high qt/lb ratios. I myself use a bag for mashing, but with 'standard' mash and sparge steps, so for me, the pH wouldn't be different, but when someone says "BIAB", we don't immediately know if they are referencing the Aussie way that often mashes at 3qt/lb or so (ie, very thin).
    – GHP
    Commented Nov 19, 2012 at 14:52

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