Oxford Democrat., 1915-07-13
VARYING Cream Tests.

nAhA0SD, Agricultural EDITOR OXFORD Dem
ocrat. Paris. Ne.
Varying Cream Tests.
No doubt, the greatest cause ol
trouble or misunderstanding between
the creameryman and his patrons is the
fact that cream tests vary greatly from
day to day.
A careful examination of conditions
may show one or more of many causes,
which are entirely under the control OF
the patron, to be responsible for the
variation.
In fact, it is usually the case that the
cream from two consecutive separations
with the same separator will not test
exactly the same when all the condi-
tions are apparently the same. One of
the most common causes for the varia-
ton in the fat test is the test of the
milk to be separated. The test of milk
will naturally vary from day to day, and
the patron usually keeps out part Of his
milk for home use, and this milk is
sometimes richer than at other times,
thus causing change in the test OF the
remaining milk, which is to be separat-
ed.
The cream outlet and skim milk out
let each take certain percentage Of the
milk running through the machine;
that is, 10 percent may be cream and 80
percent skim milk. In that case, "A
percent milk would give 40 percent
cream; therefore, on the following day,
If the milk tests 81 percent (which is
quite possible), the cream would test
only 81 percent, difference of per-
cent from the day before. The condi'
ton Of the milk may cause quite varia-
ton in the test of the resulting cream.
| Sour, ropy, or stringy and dirty milk
will tend to clog either the cream or the
skim milk outlet, and in this way
change the amount and, therefore, the
| test of the cream. 1t is also difficult to
control the inflow of such milk and this
causes variation in the test. The rate
of inflow must of necessity cause agreat
difference for a given capacity machine.
| The skim milk outlet takes care OF
given percent of the separating milk,
and other conditions remaining con-
slant, the skim milk outlet takes only SO
much of the milk, whether the inflow Is
large or small. Therefore, II the inflow
/ is lesseued and the amount OF skim
milk remains the same, the amount oil
cream must be smaller and will test
higher, as the test varies inversely with
the amount-that is, a small amount of
cream will have high test, and large
amount of cream will have a low test,
other conditions remaining the same.
In the same way, If the inflow is in
creased beyond the capacity of the ma
chine, the skim milk outlet cannot take
care of the excess, and it must escape
through the cream outlet, resulting in
more and thinner cream.
Milk is in the best possible condition
to be separated just after it is drawn
and while still warm, but if this is i'm
possible, it should be heated to 90 de-
grees Fahrenheit before being separated.
When milk is cold, the fat globules
move about with difficulty and a COM
plete separation is impossible.
With cold milk, there is not only
change in the test of the cream, but
also in the skim milk, as it will test very
high and the total amount of fat re-
covered in the cream will be decreased.
All separators have certain speed at
which they will do their best work, usu-
ally marked on the handle, but it is Il
dou btful if one-half the separators are
run at the proper speed during the en-
tire separation. Other conditions re-
naming constant, the higher the speed,
the higher the fat test of the cream, and
the lower the speed, the lower the test.
However, there is no advantage in
running a machine faster than its re-
quired speed, as there is danger of in
juring the machine, and as the amount
of cream is smaller, the amount of skim
milk must be greater, and the total loss
of fat in the skim milk would be greater.
In running the separator at lower
speed than the required one, the cream
test will be lower, but the skim milk
test will be higher (the test Of the skim
milk increasing as the speed decreases),
and more fat will be lost in the skim
milk, making the total amount of butter
fat recovered in the cream, less than II the
separator was run at the required speed.
The supply tank which feeds the milk |
into the separator should always be kept
full of milk. II only partly filled, the
milk will run into the separator more |
slowly than if the tank is full, and in
this way il will act just the same as
low rate of inflow and will result in a
higher testing cream. This cause of |
variation is possibly one of the most
common ones, occurring quite often.
All separators should be set upon a
firm, solid foundation, preferably ce-
ment, in order that they will not jar
while being run, and they should be
perfectly level. When setting level, the
milk is divided into cream and skim
milk, but when they are not level, or on
a firm foundation, the jar or trembling
of the machine is liable to cause mix
ing of the cream and skim milk, result
ing in a low testing cream, and in in
creased loss of fat in the skim milk.
Separators should be thoroughly
cleaned after each separation, as any
PARTICLES of dirt or milk left in them
from the previous separation may partly
clog the cream or skim milk outlet, re-
sulting in either higher or lower test
of cream, depending upon which outlet
is prevented from depositing its usual
proportion of the separating milk. Pos
sibly the most common cause OF varia-
ton in cream tests is the amount OF
skim milk or water used to flush the
machine, after the separation Is COM
plete. The amount used for the same
amount of milk may vary with different
separations, or the amount may remain
the same and the amount of milk sepa-
rated may vary, either of which causes
the test of cream to vary.
All separators are supplied with a
cream or skim milk screw, which regu-
lates the amount and test of the cream.
The most common Is the cream screw,
(which is usually turned inward, to get q
higher testing cream, and outwards to
get lower testing cream. When the
skim milk outlet can be regulated, this
of course changes the amount Of cream
and also the test.
When all the causes of variation are
understood and precautions taken to
have them the same from day to day, a
more uniform test Of cream will result,
or at least a better understanding will
exist between the creameryman and pa
tron, and the creameryman will not be
blamed for changing the tests, when the