hector
Well-Known Member
Hi there !
Which one has the main effect on the acid rest in a mash ?
The Husk or the starch ?
Hector
Which one has the main effect on the acid rest in a mash ?
The Husk or the starch ?
Hector
I know lactic acid bacteria are what bring down the PH and why german brewers would do an acid rest. This bacteria is found on the husk of the barely.
Hi there !
Which one has the main effect on the acid rest in a mash ?
The Husk or the starch ?
Hector
The mechanism by which mash pH is lowered at dough in are 2. In the first, inorganic phosphate released when phytin is hydrolyzed, reacts with calcium in the mash water (if any) to form a precipitate of hydoxylapatite.
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What is the main origin of phytin in the mash ?
The Husk or the Starch ?!
It is mostly found in protein bodies contained in the aleurone layer which lies between the husk and the endosperm.
If I make green malt from 2-row barley and then if I want to stew them at 158 F to make crystal malt ( Not milled ) , is it a
good idea to keep them at 122 F for 20 minutes first ?!
I mean , would this enzyme which lies between the husk and the endosperm do its job , although the seeds are not milled ?!
/QUOTE]
I think you are confusing phytin (myo inositol kis hexaphosphate) and phytase, the enzyme which catalyzes its hydrolysis into myo inositol and inorganic phosphate. Both reside in the aleurone layer. Phytase is quite temperature sensitive. It is pretty much inactivated in higher kilned malts. That's why holding barley which is being stewed at a lower temperature for a time may be a good idea from the phytin hydrolysis POV but it might not from some other perspective.
The brewer usually relies on the lighter kilned malts to provide the inorganic phosphate. Thus it is probably not necessary to treat the crystal malt in order to maximize the Pi released. Note also that phytin itself has an affinity for calcium ions and thus has a pH lowering effect in hard water.
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