>Dusty

BTW, Dusty I almost forgot about your original question which you
posted above. And I try to explain how its done in commercial
practice..and hoping you have an elementary idea how you can adapt the
principle with your household grinder.

>I have a question for those of you with home mills, do any of them
permit
>you to separate the flour? By that I mean; can I "dial-in" that I
want
>"white flour", or is it always--by definition--"whole grain"?

In actual flour milling ; whether in laboratory pilot plant scale or
production scale. If we had to mill for white flour we had to ensure
that the outer coat of wheat is toughened by adding sufficient water
to reach a grain moisture of around 15%. This value can be determined
by getting first the initial moisture of the grain and then from there
calculating the amount of water needed to be added to reach the target
moisture before the grain is subjected to milling.The water is added
and allowed to soak for at least 24 hours before its transported to the
milling rolls.
A dry wheat that has a moisture of 13 % or less will tend to ground the
endosperm and the fibrous branny matter into powder and will be
difficult to segregate the white flour from the offal
Grinding wheat with roller mill is different from stone grinding with
specialist mills for such flours. I think the latter the milling
principle is just similar to home mills, just reducing the grain to
fine particle size..I am much more familiar with the roller type mills
than the stone ground ones. Having watched the mill operators run the
production scale milling for some time I am familiar how the wheat is
gradually ground and made into the flour we see in bags and bulk
transport.. But not before I told them what to expect from the yield
and what is the expected wheat grain moisture( from that particular
wheat have to be maintained) to get the maximum yield from a grain
stock in the silo.
In commercial grinding for white flour the grinding rolls are
corrugated at different level.
It is the same thing with the Buhler experimental flour mill I used
previously.The grinding rolls run with a speed differential to ensure
that once the grain is broken the husk is actually scraped off from the
endosperm.That occurs in the so called break rolls. BTW the equipment
I mentioned has a series of breaking rolls for breaking and flaking the
wheat kernel and the reduction rolls which pulverize the endosperm
granules or semolina into flour.As the wheat particles are subjected to
series of grinding and sifiting the rolls surface corrugation becomes
finer that its literally a smooth roll at the end of the reduction
process.
So the bran comes out from the sifter as flakes( together with the
wheat germ) not in powder form by being toughened with water as I
mentioned in the tempering process.
I do not see such sort of abrading or scratching effect on the home
grinder which is more about crushing the grain into fine particle size.
So whether you had the rotary sifter that Will has mentioned , the
question is would it be able to separate the flour from the chaff
effectively?
In addition applying tempering( or the adjusting of grain moisture
before milling) would be too complex thing to do with the hobbyist
miller. As you do not have the moisture measuring equipment that
commercial flour mills have..Nor understand the math involved in its
computation.
Therefore the likely method is just to sift the broken kernels each
time its passed to the grinder to separate the flour from the coarser
particles successively after each grinding step.
The average yield of white flour from a quantity of wheat is 70% which
varies with the quality of wheat. Soft wheat tends to have lesser yield
of white flour than stronger wheat. Therefore range of white flour
yield will then be from 60-80% depending on wheat quality and kernel
size. In addition Bigger kernels tends to yield more white flour than
smaller kernels
Roy