hist-brewing: ancient ale

leaking pen itsatrap at gmail.com
Fri Feb 26 14:42:40 PST 2010


Well, for one, i believe that bourbon is done at a lower ph, not sure
which direction that pushes the curve. 2, it doesnt have to be a
complete process!  maybe not as efficient as it could be, but it
works.  http://docs.google.com/viewer?a=v&q=cache:iuK1eNpT_NIJ:www.scocia.com/newsite/American_Whiskey.pdf.pdf+barley+amylase+concentrations+bourbon&hl=en&gl=us&pid=bl&srcid=ADGEESghkoptqqn1Dx7tiwDiEI0VG-DMp-D6jaOqlCbFO74sN4-i0Nfn6Gd_8dzgSsalVHVu3gpHqqCP5WS4LU96l_NHmkIAqQj9U7Qs6YuKbRlfhxdC2GFrSV7JotX8NysniRDzKGDO&sig=AHIEtbQS8ftADespEgdPtvitrUNKAjp_yg

sorry for the big link.

On Fri, Feb 26, 2010 at 3:24 PM, Daniel Butler-Ehle <dwbutler at mtu.edu> wrote:
>
>> Its an enzyme...  keep it at temp long enough, it'll do it.
>
> Nope, it's a self-denaturing enzyme. Keep it at
> temp long enough and it disintegrates, whether
> or not it has been performing conversion.
>
> The rate of denaturing is dependent mostly on pH
> and temperature.  At beer pH and 60C, alpha-amylase
> denatures in about two hours.  At 75C, it only lasts
> about 45 minutes.  At 40C, it can last around seven
> hours.
>
> However, conversion progresses much more rapidly at
> the higher temperatures, so maximum efficacy for
> alpha-amylase actually occurs, IIRC, somewhere around
> 65C.
>
> But that's not necessarily the target temp for mashing,
> because beta-amylase, which has a different activity
> profile and temp range, is also important, so the
> usual target temp considers the combined effect at
> various temperatures.
>
> Dan Butler-Ehle
>



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