Tannins And Astringency

If you are worried about squeezing your bag too much or crushing too fine, relax! Astringent beers do not come from finely crushed or squeezed husks but come rather from a combination of high temperatures and high pH. These conditions pull the polyhenols out of the husk. The higher your pH and the higher temperature you expose your grain to, the worse the problem becomes. Any brewer, traditional or BIAB, should never let these conditions arrive. If you do allow these conditions to arrive, then you will find yourself in exactly the same position as a traditional brewer. Many commercial breweries actually hammer mill their grain to powder for use in mash filter systems because they have control of their pH and temperatures. This control (and obviously expensive complex equipment) allows them non-astringent beers and “into kettle,” efficiencies of over 100%.

[CreditNote: Dan Walker(ThirstyBoy) provided the information above.]

BIABrewer.info Notes...

It can often be difficult for the home brewer to achieve idyllic mashing and sparging conditions therefore a fine crush is not recommended for any home brewer for reasons stated here.

The claim above of kettle efficiencies being able to exceed 100% may seem strange on a first read. Further information is available here.