hist-brewing: overcrushing

BrewInfo brewinfo at xnet.com
Fri Dec 14 14:56:21 PST 2001

Bruce writes:
>Charley Aitchley is talking about really cranking down the mill to "flour" 
>his malt- he is right to be dubious about the need to do that. Modern malts 
>are genetically different from thier grandparents of the 1700's-the lintner 
>ratings are higher in today's malts, and while you might have to work at 
>toasting your malts, really pulverising the malt will release more husk 
>tannins than you want,

Actually, technically, no... the husks contain a very small percentage
of the tannins.  In Malting and Brewing Science by Hough et al, they
compared the polyphenol and silicate content of beer made from regular
barley and de-husked barley.  The polyphenol (tannin) content of the
two beers was very similar, however, the silicate content was quite a
bit lower in the de-husked barley beer, if I recall correctly.  The
majority of the polyphenols are actually in a different layer of the
barley.  Overcrushing will, indeed, increase your tannin content, but
it's not from the husks.

On a related note, one of the pro texts I have noted that 1/3 of the
polyphenols in beer come from the hops.  Note that this is probably
on those underhopped mega brews, so that in our 50IBU beers, the hops
probably give 2/3 of the tannin if not more.

>and also give more suspended solids in your boil 
>resulting in greater chance of infection (from the small islands of 
>carbohydrate floating in a sea of beer- these are excellant landing sites for 
>opportunistic infections)-

I'm very skeptical of this.  There's plenty for undesirable microbiota
to eat in beer (dextrins) even if you don't pass excessive suspeded solids
into your fermenter.

> aside from that your sparge is going to take 
>forever- if you can get a runoff at all...
>and the yeild won't really be that much better than your normal brewery grind.

This is very true and the most important reason for not overcrushing.  Note
that I made a beer with 40% malted rye once (normal crush) and it took
3 hours to take my usual 7 gallons of runnings!


Al Korzonas, Homer Glen, Illinois, USA
korz at brewinfo.org

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