of American and British Milling
Web Masters Note: The original article that appeared in "The
Millers Review and Feed Forum," was not accompanied with illustrations.
Many of us may think we have the best mills, the most up-to-date equipment,
and, therefore, that we are using the best methods of milling. We get a
jolt when we find by comparison with other mills that there is much room
for improvement. Consequently, in order to keep step with the times, we
set out to make the comparison which we have spoken of, and by so doing,
we set our feed towards greater progress, becoming less egotistical through
prying into other systems, and other methods of milling.
Only by Comparison Can Worthy Opinions be Formed
With this in mind, it will be my endeavor to try to point out to you a few
things with show up in making comparison of our American and Canadian methods
of milling, against those of Europe and Great Britain. It was in the older
countries, possibly above all others, I might mention Hungary, that the
milling industry was first developed. About 1880 the stone mills were superseded
by what we know as the roller process, this change being first noted in
Hungary. This roller process spread first throughout Europe and Great Britain,
and later was adopted by mills on the North American continent.
My knowledge of the British milling industry has been gained from actual
experience, and is not merely book knowledge. This applies to the Canadian
milling business also, having had a varied experience in every type of small
mill operated by water and electricity, and eventually, getting back to
the big capacity mills, and enjoying the experience of installing and operating
some of the largest mills in Canada.
The "Gentle Treatment System"
It was while connected with one of the largest port mills in Liverpool,
England, that the most interesting development and experiments were carried
out that I have ever witnessed; which experiments at that time were expected
to revolutionize the milling trade. The new method was called the "Gently
Treatment System." Briefly, it consisted of the idea of handling the
mill stock as lightly as possible.
The break rolls, were placed on the top floor, and the succeeding breaks
on the floors below, so that there would be no re-elevation of the break
stocks. There were tow sieves placed inside the hoppers of each break roll,
and two distinct separations were thereby made. The siftings from the breaks
passed on to very large purifiers, and the entire stock was treated before
passing on to their respective purifiers and reels. The idea of passing
the entire break stock to the break purifiers was in the expectation of
extracting a certain amount of bran powder from the break flours. This experiment
did away entirely with all spiral conveyors in the mill, and everything
which was conveyed was on belt type conveyors. The result of this method
of milling was very pure stocks to the sizings and middlings rolls. It was
not a system which was generally adopted, perhaps due to the great amount
of capital required for the extra machinery needed. However, it certainly
was a great experiment, and for those of us who had the opportunity of working
with it, as it meant a great many new ideas which have been helpful ever
Since that time many other extensive experiments have been carried out by
the British milling engineers, and I feel quite safe in saying that they
have brought about far greater improvement in the British mills that we
have seen here in the United States or in Canada. I am afraid we have been
inclined to be too self-satisfied, too much taken up with the idea of capacity,
and still more capacity; all at the expense of building up better systems.
We have crowed our mills, and thought more of a machine which would increase
the output than of installing a new machine which would improve our milling
methods. We are now awakening to the fact that we must pay more attention
to quality if we are going to hold our trade in competition with the British
and Continental mills.
As we have the privilege of milling some of the best wheats in the world,
we have every chance of keeping in the lead by paying constant attention
to the quality of flour produced on our mills. We will make this comparison
as fair as possible, treating each department of the mill in turn.
Wheat Cleaning More Thorough With Disc and Magnetic Separators
Speaking generally, the machinery used in the smuts and wheat cleaning department
of the American mills compares very favorably with that used in the British
mills. If you studied the flow sheet and made a comparison, you would not
find any great difference. In both countries the receiving and milling separators,
wheat aspirators and scourers are used. If there is any difference I am
inclined to believe it is in favor of the American methods of cleaning,
due mostly to the more extensive use of the disc separator.
If I were asked where the greatest improvement has been made in the machinery
used in the modern flour mill, I would say that it was in the introduction
of the disc separator, used for extracting seeds and oats, particularly
in the latter. This disc separator had nothing short of revolutionized the
cleaning of wheat before passing on to the tempering and condition system.
Further, there have been great improvements made in the manufacture of separators,
and it is these machines with the strong air currents which undoubtedly
prepare the wheat before passing to the next stage in the milling process.
Still another machine has come into the limelight recently, namely, the
magnetic separator, which is being used more and more for the extraction
of foreign matter, especially particles of metal from grain. The American
mills are in the lead in the adoption of this machine.
Conditioning Any and All Varieties
In endeavoring to give you an idea of the British methods of conditioning,
I would point out all wheat are washed, mostly for the purpose of first
getting the wheat thoroughly clean, and secondly, to add moisture to the
grain for conditioning, but in some cases the washing process is carried
our to even reduce the moisture in certain of the world's wheats. It is
necessary to picture the British mills having more of the world's varieties
of wheat to condition prior to blending for their mill mix that anywhere
else in the world. The wheats going into the mill mix would probably include
Russian, Indian, Argentine, and Australian, together with American Red Winter,
Manitoba, and their own native wheat. Often each of these varieties are
washed and tempered separately, each having various degrees of water and
different hours in the conditioning process; each variety being thus handled
scientifically so as to put it in proper condition before being mixed together,
and before going to the first break rolls.
You will agree that this part of the milling process is a science in itself,
and is worthy of the best brains in the milling business. So accurately
does the British miller arrange his mill mix, both from the standpoint of
conditioning and uniformity that it has been the writer's experience to
see that where one country's wheat has been excluded from the mill mixture,
it had been found necessary to add tow or three other varieties of wheat
in order to obtain the correct balancing of the mill mix. It is, therefore,
seen that the washing and conditioning process in the British mills is an
art itself. Contrast this fact with our American method of conditioning,
where practically no washing is attempted, and therefore, somewhat of a
very ordinary method of conditioning done. It possibly may be said that
in this country it is not necessary to go to all the trouble, due to the
excellent wheat which we have the privilege of using in our mills. However,
as time goes on, and our wheat get dirtier, due to the land become poorer,
and more contaminated with weeds, it will behooves us to make a closer study
of the art of conditioning and to my mind, we may well copy the established
practice of the British mills in this respect.
Thoroughly Washing All Wheats Produces Better Flour
I feel confident that in the near future we will see adopted in our up-to-date
mills the general policy of washing all the wheat which goes to make up
our mill mix. It is only reasonable that if the wheat is thoroughly washed,
we are bound to have a flour of better color, with less foreign matter,
and consequently less bran powder and less ash. As we progress in this art
of washing, so will we improve our methods of conditioning, which will open
up another field for development, and that is the principal of heat in relation
to more perfect tempering of the mill mix.
I would like to give you a few points regarding the importance which the
British mills attach to the conditioning of wheat. By conditioning I mean
distributing the moisture content of the grain so that the best and cleanest
separations are made during the subsequent milling process, and at the same
time, the baking value of the flour is improved as far as possible. There
is a great deal of difference between the grinding of wheat which has been
properly conditioned, and wheat which has not passed through this process.
In the former case the bran comes away cleaner from the endosperm in large
flakes, with very little pressure on the rolls; the sizings are clean and
of an even shape and size, so that the purification is very much simplified.
The power consumed by the mill is substantially reduced, and the work done
by the bolters and reels is more improved. Wheat which had not been properly
conditioned makes poor sizings, small bran, and an excess of bran powder,
most of which eventually finds its way into the flour. Conditioning has,
therefore, become one of the most important processes in connection with
British Modern Conditioning Method
In British mills they have a machine for this work of conditioning, known
as a "Conditioner," and vast strides have been made in perfecting
same. This machine is after the style of the one which we use for drying
purposes when handling tough wheat, but the British millers uses this "Conditioner"
on all the wheats milled.
To our mind, conditioning of wheat on this Continent means only applying
water and putting it into bins, whereas, by the British method, the wheat
is passed through a modern conditioner, where the application of heat is
scientifically carried out, and far better results are obtained. We all
know some wheat need the moisture driven into the grain, and in others,
the moisture needs to be extracted. All this is done in the British mills
by the aid of this "Conditioner." Moisture, heat evaporation,
and humidity are all scientifically controlled by this type of machine in
handling the wheat, preparing it for the first break.
Web Masters Note: The author may forget that in American mills, the
tempering and conditioning bins are located in the mill's attic or upper
floors where the added moisture with heat, heat evaporation, and humidity
are administered by nature without the aid of an additional machine.
I would urge all millers interested in those latest types of conditioners
to make a close study of their value to the mill. If we are going to keep
pace with the British miller on the export market, and improve our own domestic
flours, the day is not far distant when we will have to use similar equipment
to that which is proving such a success in the British mills.
Purifiers and Purification
This very important department of the milling industry has never seemed
to receive the same serious consideration as it has in the hands of the
British system. As we now stress very much the importance of ASH, it is
quite apparent that the purifier plays a very important part in the regulation
of this, which some millers feel is the BIG thing in the milling business.
It is will know that the progressive millers of the United States and Canada
are becoming more and more aware that the ash content is the one great test
as to whether the mills are performing properly or not. The operative miller
soon realizes that his job depends upon his turning out a flour containing
an ash content as set by his company, and if he is unable to deliver the
goods he soon loses their confidence. I think it is good for the miller
to have to live up to the requirement, although it might cause him sleepless
nights, or even if he does sleep, he may dream of the ash bug-bear which
confronts him at all times. But without doubt, the miller becomes more efficient,
and keeps the mill under better control than he otherwise would without
having to live up to certain requirements.
You might as what has ash to do with the comparison of British and American
methods of milling, and my answer is, it is one of the most important departments
in the milling process. Taking for granted that the wheat is properly cleaned
and conditioned, the purifier undoubtedly plays one of the most important
parts in producing clean stock for the rolls, with a minimum amount of ash
in the flour, and in my mind the British miller has it all over us in having
improved purification and cleaner stocks. Not only that, but in training
of the British operative miller is more thorough, as he is made to realize
that the purifier is a most vital and important machine. That it requires
constant attention as the grinder gives to his rolls. Whereas, we so often
find that the purifier is the most neglected machine in the mill, due to
the general run of purification not realizing that it is the proper method
of milling. Good purification means good milling, and if were asked to check
up a mill, I am sure that we would want to see the working of the purifiers
as much as any other department. In fact, I would say let me see the working
of the purifiers, and I will at once tell you if the mill is turning out
a good quality of flour.
Many Types of Purifiers
There are many types of purifiers, briefly outlines as follows:
1. A standard tinless machine such as in common in our American and Canadian
mills. It is will constructed from an engineering point of view, and in
which all the liftings go directly through a high velocity channel to the
dust collector, and the heavier impure particles over the tail.
2. A machine with a small high velocity air trunk stretched right across
the sieve at the tail end of each compartment so as to carry away all the
excess matter which is left on the silk by the ordinary tinless machine.
3. The standard British machine, fitted with tins stationed above the sieves,
running the full length of the machine.
In comparing the different types, I have always considered the British purifier
fitted with tins to be the most effective, making the most perfect separations
and cleanest stocks. I am hardly prepared to agree with an opinion expressed
with says that the American type of purifier is definitely inferior, but
I must say vast strides must be made to improve it, if it is going to perform
the work we would like it to do.
Grinding - Fast and Slow
Overloading Capacity versus Quality
The chief difference which the writer had found between the handling of
stocks on the rolls in our American and Canadian mills as compared with
the British methods is as follows:
In the British mills the rolls are run very much slower, with much lighter
loads, and consequently the result is more accurate grinding. They are extremely
against the heating of the stock when grinding, and the writer has seen
many a man discharged because the British superintendent on his rounds in
checking over the grinding, found the rolls warm. Our idea over her had
been, heavy grinding on our rolls, with the result that our stocks have
not been as evenly and as finely reduced as in the case of the rolls carrying
To illustrate this, the British milling engineers figure as high as 3 1/2
inches per barrel; roll surface, whereas, we boast of only requiring as
low as one inch per barrel, and think we are performing wonders. The stocks
going to the sizings and middlings rolls are indeed much better classified
than in the general flow of our American mills, with the result that they
are not up against the same difficulty of producing a uniform flour, particularly
where the ash content plays such an important part. There are certain disadvantages
of the British rolls - principally their exceedingly long length. For instance,
their 60 - inch rolls, which are used on the breaks, and the 40-42 inch
on their reductions. On this side we favor the shorter rolls, the same having
greater accuracy. Of course, the large roll with us would be an absolute
impossibility, on account of the heavy streams which we put on them. It
is also interesting to not that the British rolls on the middlings often
carry as high as 60 to 80 corrugations per inch. This can successfully be
done done due to the wonderful double feed rolls feeding a think stream,
and also because of the special attachment on the rolls themselves.
The drawback of good grinding on our rolls in the United States and Canada,
as before mentioned, often due to our desire for capacity. We overload our
rolls, and instead of a thin feed going to the roll it is often otherwise
on our systems, with the result that instead of the rolls themselves reducing
all the stock, a percentage of the stock against stock is reduced. The consequent
result is that the material is unevenly ground because of the lack of proper
feed roll delivery.
Compare the improvements on the British rolls (except for their length)
with those manufactured here, and it is at once realized that we are not
as well off in this respect as the British miller. We have seen very little
improvement in our roller mills, and there is a distinct lack of better
feeding arrangement of the stock to the rolls, in comparison with the double
feed roll attachment on the British roller mills.
Bolting With Silks 16 to 18 XX
Some of the features in connection with the comparison of the bolting principles
of the British mills against ours are as follows: Only a comparatively few
years ago the entire bolting and sifting machines in the British mills consisted
of round reels and centrifugal reels. Very few sifters were used up to 20
years ago. Since then, sifters have been favored for handling the break
scalps, but these machines were never used for bolting flour. They still
cling to the centrifugal reel for all their flour bolting. Undoubtedly,
we have made far greater strides in this department, and some of the types
of our sifters are no to be equaled anywhere in the world. Possibly there
is an explanation for the British mills continuing to use the centrifugal
reel, in the very fine flour which they produce.
It has been my experience to use the centrifugal reels clothed with silks
as fine as 16 to 18 XX. You can well imagine how almost impossible it would
be for us to bolt flour as finely as this on the ordinary sifter, and it
is perhaps for this reason that the British have stuck to the centrifugal
reel for their flour bolting. The moisture content of their flour is, of
course, much higher than ours, which has been another reason for keeping
this type of machine. Those of you who have closely inspected British made
flour, will have been impressed with its wonderful dress. It is practically
free of any specks, due, of course, to the careful purification of their
stocks, and fine bolting, coupled with the higher moisture content. All
of which tend to produce a flour of a very high color, and very fine granulation.
In comparing the British against the American methods of machines used for
collecting dust both in the smuts and in the mill, I feel that there has
been far greater advancement in the British mills than in ours. Speaking
of the dust collectors, in the mill proper, the problem in the British mills
has been reduced in somewhat of a minimum due to the fact that all their
machinery runs cools, and that they are not generating the same amount of
heat, as is done on our mills. They have types of dust collectors, particularly,
the suction filter type of machine, where they can take in the entire roll
dust into the machine, and deposit the air back in the same room, practically
free from dust. It has often been the writer's experience to see this done.
It is such a contrast to even the best dust collectors which we have in
The minimum of heat generated in the milling process, due to higher grinding,
and from the fact that the dust collectors discharge cool air back into
the room, gives better control of humidity in the mills than we experience
in the States or in Canada. Therefore, it is important that we endeavor
to make greater strides to improve the types of dust collectors used, and
also to improve the humidity control in our mills.
Briefly, I would like to describe the suction filter type of dust collector,
which I consider the most efficient one on the market. It consist of a nest
of sieves enclosed in a close compartment which is connected to the suction
fan. The dust laden air passes first into the hopper and from the hopper
upwards into a number of vertical textile sleeves which are generally about
eight inches in distance. The air then passes through the sleeves into a
closed air chamber, and from this away by the clean air outlet to the fan.
By means of a mechanism the outlet to the fan is at intervals closed, and
the compartment at the same time opened to the atmosphere. In this way a
reverse air current is drawn from this opening through the sleeves into
the hopper, and so through the other compartments to the fan. While this
is happening, the same mechanism shakes the sleeves. This shaking combined
with the reverse air current, cleans the sleeves with the reverse air current,
cleans the sleeves very differently, rendering it possible to use a fine
cloth without any risk of choking.
The result of this machine is that the air is delivered so clean that it
can be blown straight into the mill and the interior of the machine is always
below atmosphere pressure, so that if there are any leaks, they are inwards,
and not outwards, and no dust nuisance results.
For Cleaner, Healthier, Safer Mills
It is interesting to not that the British mills, the Cyclone and this type
of dust collector are used. In the United States, and in Canada, the Cyclones
and Pressure dust collectors are still the commonest type of machinery used.
Practically every miller here, I think, is dissatisfied with the progress
which has been made in the type of dust collectors used on this Continent.
It has been said by a British writer that the majority of the millers in
Great Britain take more pride in having a clean and well-kept mill than
do the millers in the United States, or in Canada, and I am afraid that
there is a great deal of truth in this statement. Therefore, it behooves
us as operative millers to endeavor to make a greater study of the dust
collecting system, and by so doing, have cleaner mills, healthier to work
in, giving the mill operators a greater incentive to take pride in the general
upkeep and appearance of the mill. Then, of course, there is the financial
bearing of this matter, more of the dust would actually be collected, and
a greater amount of dust recovery could be made.
To Produce the Best Flour
As operative millers, it is always our desire to have the best and most
up-to-date machinery, in order to produce the highest class of flour possible,
but to do this, it cost money, and in making a comparison between British
and American methods of milling, we have to take into consideration the
capital cost involved, and the relative cost per barrel. If you studied
a British flow sheet, as compared with ours, the greater cost of machinery
used in the British mills would be quite apparent. This with their longer
system, means a greater cost per barrel. Without any doubt, our cost per
barrel, both in the United States and in Canada, is the lowest of any country,
when capital cost is taken into consideration.
It is our desire not only to make the highest class of flour possible, but
to produce it at a reasonable cost. To do this it is necessary for us to
be on the alert studying the milling methods of other countries, ready to
adopt improved machinery and methods, and to discard the unprofitable and
out-of-date machines which we have been content with in the past.
In making the final comparison between British and American flours, we must
remember that a flour which will suit the purchaser from the British miller,
may not suit the purchaser of flour from a miller in the United States or
in Canada. We are making distinct types of flour, both from the spring and
fall wheats, and as our wheat are of such high quality, it naturally follows
that our flour does not need to take second place to any produced.
The criticism which I have offered is with one object in view, and that
is in the hope that we, as operative millers, will not rest content, thinking
that we are making the best flour, but to try for a higher standard, and
to do this we must have the co-operation of all the operators in our mills,
each man giving his best, which, together with the aid of our milling engineers,
in producing milling machinery of a higher class than ever before, will
insure a forward march in the milling industry.
Web Masters Note: The demonstration miller knows or cares nothing
for these things. They are directed or mandated to grind our more words
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