xt79s46h2m5t https://exploreuk.uky.edu/dips/xt79s46h2m5t/data/mets.xml   Kentucky Agricultural Experiment Station. 1924 journals 002 English Lexington. Contact the Special Collections Research Center for information regarding rights and use of this collection. Kentucky Agricultural Experiment Station Regulatory series, bulletin. n.2 text Regulatory series, bulletin. n.2 1924 2014 true xt79s46h2m5t section xt79s46h2m5t   r     4 . ‘ · I i
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. lidegulatory Series:—No. 2. Revised, April, 1924.
— Kentucky Agricultural Experiment Station
· I L i UNIVERSITY OF KENTUCKY
, , THE BABCOCK TEST FOR BUTTER FAT ·
I if I The Babcock test affords an easy and correct method for _
I determining the amount of butter fat in milk or its products.
· It is the method in general use in this country for ascertaining
the percentage of butter fat in milk and cream. It depends
, upon the action of sulfuric acid on the milk or cream, using a
special test-bottle and a centrifugal machine for bringing the fat
_ itogether in such a way that it can be measured. The test is ex- `
• tremely useful for ascertaining the butter fat production of in-
dividual cows in a herd and for rapidly determining the per-
centag·e of fat in milk or cream brought to a ereamery, cheese
factory or milk depot. ·
Average milk is composed of 87.0 per cent water, 4.0 per
` cent fat, 3.0 per cent casein, 0.5 per cent albumen, 4.8 per cent
V milk sugar and 0.7 per cent ash. In the Babcock test, sulfuric
acid of 1.82 specific gravity (65° B.), or about 90 per cent
strength, is mixed with the charge of milk. The acid dissolves
all constituents except the fat which is set free and rises to the
. top of the hot mixture, in a melted condition. Separation of the
Y fat is hastened by the use of a centrifugal machine or "Babcock
tester," and by adding hot water to bring the melted fat up
into the graduated neck of the tcst—bottlc, where it may be meas-
ured.
. Observations made during inspection work and in testers’
license examinations indicate that cream station operators are
often lacking in detailed information concerning the testing of '
milk and cream. An average of one operator out of every six has
failed to pass a satisfactory examination in the operation of the
Babcock test for butter fat, and many who-do pass barely reach
the grade of 75%, which entitles them to a Certificate of Pro-
. _ iieiency. Four or tive weeks of actual cream-station experience
Should be sufficient to enable an operator to qualify for a tester’s
license, and yet many fail with even longer experience. In such
· *""’ ’ i `!1¤§'j;Q ~· 1,·,;< g
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, i I ·`.i       '?i=3,¥ti€?=¥·_i`<,·»"'[ 2.  é::¤· c 7  
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’ ' "··~·`__ `_ mf ’· `· ·. $1 _, _’ 7·_¢;}?•~'Q‘5;.'é";·»f:
FIG. 1.—Good equipment for testing cream and milk by thc llabcock
method. Note the compact :trr:in:¤-1nr·nt. A. Hot `Watcr Tank. B.
\\'ater Bath. C. Tester. IJ. Can for Glymol. _

     ‘  ‘=3*  i ti » `
“ `· 1 The Babcock Test F02· Butz‘e2_· Fat _ 3
A   I , 0 ljmeters above and below the graduated part. The capacity of
K i U 5 - the bulb must be not less than 45 cubic centimeters and the total
`S   height of the bottle must be between 150 and 165 millimeters
V 1 (5 7/8 and 6% inches).
_, ` A   ‘ ·   _ _ t·“.      
‘ 5 - , ‘ iu ‘ , ‘ Y I _. ·
  e_    -··_     ss; 4 ¤
Y   .- ,·: Q ,  
6 if ir    ` T  ZZ;   · l  ii- `···  
{ T ·tii  i 5  0 i_  tf}.-j»   ·`,t. ; s_t“  
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FIG. 2.—Stztndurd milk and cream test-bottles.
Babcock Cream Test-Bottlcsr, of which two types are al-
, lowed by the Kentucky law; the sh0rt—ncck, 50 per cent, 9-gram
` bottle, Fig;. 2, C, and thc long-neck, 50 per cent, 9-grain bottle,
. ‘ · · Fig, 2, B. ` .
(a) The short-neck bottle is of the same Q_'("llC1`2l»l. style and
Q T dimensions as the stz1ndz11·d milk-test bottle, except that the neck
lL_____________i___ _ .. 5

   _ {alt
" ‘ 5
3 4 Kentucky Agricultural Experiment Sta-tion
, Of is wider. It is intended for a 9-gram charge of cream, and must
mil be so marked on the neck, above the graduation. It
lem , is graduated for a total of 50 per cent, the sub- l
g J divisions representing 5 per cent, one per cent and i
    5/10 of one per cent. This is the type commonly
L ` used.
I _ g __ g   _ (b) The long-neck bottle is 210 to 235 milli-
meters (8% to 8% inches) in height and the grad- i
G uated scale on the neck is not less than 120 milli-
meters long; in other respects, this bottle conforms
· 3 to the specifications for the short-neck cream bottle.
-5   The long-neck bottle is too tall to be used in the or-
  ’¥ dinary Babcock centrifugal machines.
_     17.6 cc. Babcock Mil/t Pipcttes (Fig. 3). These
  "° must conform i11 their dimensions to s ccifications
p     prescribed in the law. p'
V ‘ ` Ji A 9-gram cream- wciyizt for weighing 9 grams
j' of cream into the test-bottles.
  All the foregiong apparatus must have been
if inspected and approved by the Kentucky Agri-
-·   cultural Experiment Station before it can be le-
‘ · gally used within this State in testing milk and
{ e I, cream for the purpose of buying and selling tl1e
- s a m e o n t h e ‘
. basis of butter- s
Fg;nd:;rd— fat content.  
milk pipette Babcock testing  
glassware and cream weights  
which have been thus exam-   T
, ined and approved are per-   ,.._,  
manently marked with the     g ,  
letters "S. G. K.," meaning "  ‘___ ’         _1   
l- "standard glassware, Ken-   V'>_‘   ,; Vii.,  
11 ' tueky."   A U   '.'_ .{’
e, In addition to the forego-    ,1,* ‘·__.``»' ·   ix
ing standard apparatus, the ,- {it il 
1 following will be needed: F1G_ 4.—Terse1n balance No. woo.
{

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§¥¢ II    
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·?§‘1   ._ ·
  ?}:-      
¤   iv, Q_ r   . . ,r..· :
. 2I:c     °‘ ,  ~ . I
’ -   . The Babcock Test For Bzzlter Fat 5 I
I » . I I
I I . ° fd` * ~· ream-Test Balances. Several tv cs of scales for wei hina
I ` » P D V
. Q I ’ , `— the charge of cream may be used. A good kind is illustrated in j
. =   I — i , 4. A one—bottle scale is to be referred as being the most I
g 2 D I
‘ sensitive and accurate, tho the two-bottle type is quite good. I
. I Multiple=b0ttle scales. that is. those in which several test-bottles ‘
I *1 are balanced at one time, should not be used. · ` .
. , The scales and weights should be kept I
_  3. T" I   scru ulousl ‘ clean and iroteeted from cor- I
~ r s  is   P y I I
 $21 ; —`   Q ,1 rosive substances, such as acid, salt and  
QE ii gi g WHt€I`. I
- if  ta? . , . . I
I ·   _ _ A measure for acid, which may be a  
  glass di J er of ro cr size Fig. 16 a small '
 ,4;, ; me __; I U I P J 0 1 I
  1F    glass cylinder graduated at 17% ec, Fig. I
{5      5, or one of the special eontrivanees for I
*‘·-<   . . , . .
    F?}  , delivering 111:; c.e. of sulfuric acid several
4*% any  O . -1 . ` ’ I
-   ,7.§§`*Y#§ forms of which are obtainable from dealers. I
` I lgébf  . ; , ;
I - * ‘··  _ . A ·wa2‘cr-Zxaili, Fig. 6, and Fig 1, B, in I
. which the test—bottles can be brought to a .
FIG 5 _ACid temperature of 135 to 140° F. before read- ·
, measuref 1Dg tht} fat. ·I
I I
, Q is  ' I
@1; ·I· »r alr’  {II    
 ’ wa .  TI xt :  at 232 To :5- `  `   I
         #2:
`  ‘=.~—    `_  .f'i*"··i.·   T my . ·*y  ¤s ’—. =··
      V    
        ·/    ·
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M   ·‘*%~:¢·,. I. ·   *··»·- ¢:—·    wp aa.
I!~$,.>€g, `  `.:<.··. ,§ yl w'·"· ;»¢;?·: ’€.~# ’r ~ — —
  `·¤;·   = ;’ ' · *‘*
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 yggébj nazi?] ,  i:._,~»Esi:$$g=i_  w;:#,_ >_ ,, , l
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. `2"Y     `=’ I ¤‘    · *·*'{# `  "   
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FIG. 6.——\\’ater bath. ·
é
  A
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  `
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5 i 6 Korztucky Agrz`cuHz1raZ Etcpcrinzcnt Station
) .
lling   . A Babcock z‘csgfer 0r centri-
d in   `  7  fugal machine, Figs 7, 8, and
Iwst     4  9, of a size appropriate to
OOd_ l   the amount of testing to be
btles ·     4 rm.]  " done at one time. The steam-
, - ,1,  '?g’·}.;.     turbine machines, Fig. 9, and
  ir F   0   Fig. 1, C, are very advan-
kept I FIG. 7.-A f0ur—b0tt1e tageous, where much testing
cor-   hand test"' is done and steam pressure
and   is available. The electrically
! _g·   driven and hand driven ma-
le 3~   gewzciii .-  f-get ehincs are very satisfactory.
Dim i *—-E;. ..       Macllilles having an odd num-
@18*   ·    .- Yi ;  ber of bottle hangers are to
xii;   ·-V.  Y  ——‘=. be avoided, because it is dif-
gm   F .I V,',’   {2* "`·’ Q,  Heult to balance them, when
_ V   _·  all the hangers are not in use.
2,12     The eonnnon form of I0-bot-
ad_ V T" tle machine having five hang-
ii FIG. 8.—An enclosed hand tester, CFS, each for two bottles, is
undesirable on this account.
i I   A good tester must be earp-
`V MéM ;` _       able of being driven at a high
·     xgj speed. An 18-ineh inaeliine
     I   '\   A should be run at not less than
i  ill?    S00 revolutions a minute; a
  12-ineh maehine at not less
`.       ,[__   than 1,000 revolutions and
—   · N il;     smaller machines faster in
V FIG. 9.—A steam turbine tester, IlI`(*lVll`ii‘)U·
`
{ .

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ia,    ‘  T   S   .  
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‘ T-   Tg QT The Babcock Test For Batter Fat 7 {
{ L   A pair of cliuiclers, Fig 10, for measnr-  
  ,    hr  ing the fat-column. These are indispensable   ·
. ·   __   for rapidly and accurately reading the per-  
T FV, - . y ’'V>    jj centage of butter fat. They should be of sub-  
T T T .   stantial construction, with line points and a `
Q ·     joint which permits sinoth movement but firm
’ .j§{   enough to maintain the position of the arms .. ..
U ‘   _,   when set at- any point.
` I _   Suitable bottles for ” A  {
i T   T7 , samples, which may    V '_ it
..T -T    be tlie regular milk-   g T  
·   .T     bottle of the dairy,     T
  i`   -.   "ideal" jars, wide-    _,_ i   y
i     mouth, stoppcred bot-     N
— if i   tles or the like, Fig. ' i
  2- · -;*2; L, FIG. 11.—Samp1e bottles
‘ g · .   ig V   11- for milk and cream, `
      Other Applz'a.nccs. Sonic arrangement for
4 y  QT   taking samples, such as a combined stirrer .
Y T T; T   T and dipper, Fig. 19, No. 1, or one of the
. 7 i ‘     several kinds of sampling-tubes sold by sup- y
g it .   ply houses; cream transfer-pipettes for use in `.
’   Q transferring cream into test-bottles; small ri
r T   _ L ·   brushes for cleaning the necks of test-bottles;  
i T T some arrangement for adding hot water to the i
l FIG· 1°·`D“Tid“S test—bottles, Fig 1, A and Fig. 9; a small oil  
. can for handling Glymol, Fig. 1, D, and other conveniences
· { which will suggest themselves to the worker. Tables to aid in
· computing the value of milk or cream from the percentage of
butterfat found are obtainable from dealers in creamery sup; p
plies and are very useful.
‘ MILK TESTlNG*
i Taking the Sample. The value of the result depends as
much upon a correct sample as upon any other factor. When
. milk'or cream is allowed to stand, the particles of fat, being rel-
. T ' Applicants for testers license are exaniined on milk testing as well as  
cream testing. The law requires that ereani-:
l ·»_·   `;;i-·    _j. V;    . _`   . < ll
.. Vi Q aT ~ is T; ~V-~'- '   .`·t- Q »     tt -4 T
· · M' `  Y ,. ‘   —·'··‘ I--Qt           · »
· ‘· —     ~ 5 ._·.   »¤A-   ·_-¤·· ; ,_._~           ·
l A     T   Fi `·-` gy     ‘-;». at J»’·  "Nf.   ` ‘t>V _
l · 1 1         _·.‘4’     i  
t _ bk . • i'   _;       _   _ ,·. `A U I
  FIG. 13.-Adding acid to milk-test bottle. F
  Adding the Acid. Add 17.5 cubic centimeters of commer-  
i cial sulfuric acid to the test—bottle containing the measured p01·- l
.Q _ __i___$_ tion of milk. Tl1e acid should be at
Q` » ‘ll·,_ 55 to 70 degrees F. and of a spcciiic `
  {2 ··‘‘   5;    gravity of 1.80 to 1.83.- The bottle
Q PQ / __ / should be held 111 an inclined position
   "   and the acid allowed to flow slowly
. :  . down the inside of the bottle neck, ,
, `   »._,i*·—r..____ Fig. 13, to the bottom of the bulb,
    iz;   forming zi distinct layer separate
      '·__·   from the milk on top. It must quick-
‘ {_ _`   l_:·‘i‘>°i.. __,;;ii' ly be mixt with the milk, by giving 1
  ] , 1 ,,:*7   the bottle a rotary motion, Fig. 14.
{ Y Q A     '1`he mixture gets hot and should pro-
1 ‘~    . .° .
. . No   4 duce zi liquid, coffee-brown in color,
1 , miiumtiizihgiilggiig   H0‘¤ COHtHini¤g any flakes of undis-
_ to mix me and min:. solved curd or charred particles. A
_ 1 Whiirling the Bottles and Adding Water. The next step is
g to separate the fat by whirling the bottle in a centrifugal, Figs. _·

   'T l ·   -`*e§s¤€:;<;:1-E _ .
it   Y »
V-   The Babcock Test For Butter Fat 11 ii · 5
V T V i 7, 8, and 9, and by adding hot water. First whirl the bottle for
  e five minutes at the proper speed for the particular machine.
i (-All 18-inch machine should be operated at 800 revolutions a
i, . minute, while a 12-inchtester should revolve 1,000 revolutions
T ‘ ia minute. If the machine is not full, it should always be bal-
. · aneed by having the bottles opposite each other. A test-bottle.
M filled with water should be put in opposite an odd test. _ At the
end of five minutes stop the machine and add hot water suiti- · -
cient to bring the contents up to the neck of the bottle. Next
i whirl two minutes and then add hot water to bring the fat up _,
into the neck of the bottle, almost to the top of the graduations,  
» · dropping the water directly on the fat to wash the fat-column _i
i of charred material. For this purpose use clean, soft water. If ,
the water is hard it may sometimes be softened by boiling; it is Q
” ¤ better to use rain-water or distilled water. Finally, whirl the  
T F bottles one minute.  
_ After the whirling is completed, place the bottles in ia water  
A bath, Fig. 6, for at least 5 miuutes where they are surrounded by 1
‘ hot water at a temperature of 135 to 140 degrees F. The  
1 water in the bath should reach  
V . to the top of the fat-column.
Reading the Percentage 0f l
A _ ,7__ ___________, A Fat. The fat-column will be of  
" "B a straw color and clear, if the ‘l.
test has been correctly made.  
, ’ A small dip o1· curve called the
meniscus will be found at the f
I , Read from A [O D top of the fat, and a less pro- lgi
— ' — nounccd one at bottom. In test- F
ing milk, the measurement of  
the fat-column,_Fig. 15, should.
be taken from the lowest point ,
_ A :.5; ____________ D of the curve at the bottom to the ~
$ top of the meniscus. Some fat
still remains in the bulb, but it Q
. ` — is small in quantity, and allow- l
_ ` ance is made for it by reading g`
_ 1 Fig? 1Q@§",‘;Q§f` ‘“°“‘°‘l of "°“'l‘ to the top of the meniscus. Z
%   I
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2 le
12 Kentucky Agricultural Experiment Statimz, ·,iV
I A pair of dividers, Fig. 10, must be used to read the pe1·- f
l · centage of fact accurately. Place one point of the dividers op—  
posite the lowest point of the fat-column and the other point Q
— opposite the top of the meniscus, to measure the exact length of *
. t
_ the fat-column. V\71thout changing the adgustment of the d1-  
  _ _, _ , viders, rest one point on the zero mark, and note where the upper  
` ` I
» - point reaches on the graduated scale, Fig. 17; this reading gives I
, ` the percentage of fat in the milk. i
i' ` Dark fat—c0lumns, or those containing charred material, re- {
  sult from using too much acid, too strong acid, or having milk ~
wr . . .
1:, or acid too hot; white or curdy fat-columns result from opposite
~l. . . ·
  causes. Great care should be taken to have everything right, to r
,j insure correct tests, ·
II,
gi .
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wl - ·€ .::}re·=`$   . qv? ‘ ·  -..i "Q 2,, ··V °   . · V ` ° ‘Nv V
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.| iz?  7  ‘ ·~;`;?lV%·€··Tf<:=;r». ' · "—~.$-..`I?.J   ;‘&§¤  ‘ ‘   ‘
2 s'\@$' .,- ¤?.»».»,  ;i¢•‘.·i’·‘i··;· ‘·:···.·2·"‘L·=:. ‘q-- ¤*, ~   n:·!.' · ·‘
. ‘ i,&Z;·.¥*-‘i--;i¤L."`if§   "¢:€   ·" "‘*~Z,¢i¥¢.·:%?7'·’ “    .
··     .;;-,4-s 1 .-.1..-. .‘·`   · " ···? ¤·'»; · *3     · ' ·
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l  l<+f.l‘»~?‘¤?1F`i~·¤;*I   R ·— V _ ·
  ' FIG, 1•3.—Mcth0d of adding acid to cream tests.
ni V
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I ’ , .  The Babcock Test For Butter Fat 13   T
  .;; .. . ;. . CREAM TESTING
A   · ey P. E. BAcor~1.===
T T _ 1. SAMPLING CREAM.
_ T The iirst important step in making an accurate butter fat ‘ V
T A test is to seeureé, representative samplei Wliere cream is smooth f; _
and easy flowing a correct sample may be obtained after the A
T cream has been thoroly mixt by stirring or pouring. But, un- Ai
T fortunately, all cream is not smooth and in the best condition *3
for sampling. Cream often is lumpy, clabbery, thick, frozen, or T,
» , partially churned, and ordinary stirring will not distribute the g}
` butter fat uniformly. But stirring, supplemented by other `{
l treatment, will usually result in a uniform sample. `}
Lumpy Creamt. Lumps will oftentimes dissolve when the ·`
V T T cream is well stirred, unless they are too large or too firm. If
` vigorous stirring does not break them up the cream may be L
T warmed until the lumps disappear; altho warming is objection-  
able from the standpoint of quality, since it tends to cause the .
multiplication of bacteria. A better method is to pass the cream
thru a funnel—shaped sieve made of strong galvanized wire (one- ?
eighth inch mesh). Lumps remaining in the sieve should be {
·prest thru with the stirring rod and the cream thoroly mixt l
before the sample is taken. The sample should not be taken
— while lumps of cream or curd are present in the 1ni>;ture..  
l Curdy or Cltzibberg; Cream. This type of cream is preva-  
I lent in warm weather. It should never be heated, as heating l
- toughens the curd, making it more difficult to break up, and ’i
therefore more difficult to sample. Use the sieve, as with T
lumpy cream, stirring thoroly after the curd has been prest thru. · T
It is necessary to take the sample while the cream is being stirred,  
as curd quickly settles after stirring has ceased. If no sieve is J
i available, break the lumps as fine as possible by stirring.
Tltick C'reunz». \Vheu cream sours and cools it becomes ,
P i thick and viscous. _ If such cream is very rich in fat it may be-  
. ° Resigned.  
i  
I .

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i ..
ul . · 3.
gl °
it , . . . l
:· . t 14 Itemfzzeky Agrzculturrzl E.rpcrzmem‘ Statzon »
la
  come so thick that stirring is well-nigh impossible. Operators ~
° have been observed to sample this type of cream by simply
~ dipping a sufficient quantity from the surface without stirring. lj
Incorrect tests are the result. Such cream must first be warmed ‘
‘ until it can be easily stirred before sampling is attempted. .
· i l Frozen Cream. Care should be taken not  overheat frozen Q.
lu cream in thawing. Warming should be gradual and should not f
‘f l it T exceed 100° Fahrenheit. Excessive heat liquities the butter fat, l
l causing it to "oil off," a condition unfavorable to accurate sam— ’
X] pling. Allow the cream to thaw at ordinary room temperature
  when practical.
  Battery Creanzi. The condition of this cream is due to par-
li tial churning. It must be heated in order to melt the particles p
  of butter. Some of the fat will be liberated, or melted, in the I
,· process of heating, but this is unavoidable. The cream must
Q. then be stirred rapidly and thoroly and the sample taken at once
A; before the liquitied fat rises to the surface.
  Composzite Su-tuples. Because cream is thick, viscous and
. rich in fat, it is almost impossible to secure a reliable composite
A sample from a number of cans. Composite sampling of cream. is
i twzlazofzzl ta Kentucky.
l Careful Sampling is lV0r/It W/elle. Some operators may
it feel that these above instructions for sampling can be followed
I' only at the expense of time and labor. This is to some extent
li true. But when it is remembered that, as often a-s not, inaccur-
Q ate tests are due to improperly sampled eream, thc conscientious
i operator will take whatever of time and labor is necessary to
`V insure accuracy.
'   PREPARING THE SAMPLE FOR TESTING.
1 '
t   ll'ormz`ag and .l1z'.rz'ng. If the sample to be tested is cold,
i i thick or lumpy, it should be warmed in a. shallow sample bath
T ‘ at a temperature not to exceed ll0* l·`aln·enlieit. A higher tem-
* g perature is in violation of the rules and regulations of the lix-
‘ i perimeut Station, and may cause the sample to "oil ol`t'." A _
l
l

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, ill,  W · I ¤`    °
V yp,   ;~.   _
    T  `   nl _` The Babcock Tcst For Butter Fat 15 Z M
Vai T   special pan, three or four inches deep and large enough to ae-
    2 `T cqmmodate about a dozen sample jars, should be used for warm-
  Qi ii¤g_ Samples will become overheated if placed in the regular
ii * hot water bath. After all lumps have dissolved and the cream
  I Hows easily, mix the sample thoroly and immediately draw up
T ~T ’ a portion into the cream pipette for weighing out the nine-gram ` 1T
"V charge. Some operators 1nix the sample by stirring with the pip- ‘ TT T T
ette or by shaking the bottle vigorously, but the method recom-
A mended is to pour the cream back and forth several times from
i sample jar to some other receptacle. Stirring alone, unless very
i   thoroly done, will often result in a poorly mixt sample. If the
p ·1nixing is accomplished by shaking, care should be taken not to M
l T shake- too long or too violently, as instances have been observed
- where this procedure has caused the cream to "churn, " resulting ,.'
in thelformation of lumps of butter. \Vhcn mixing is done by Q
pouring, the receptacle used for that purpose must be rinsed
i T with hot water a11d allowed to drain before the next sample is V
` mixt. ·
s T Oily Samples. Cream that has partially churned will oil  
off at temperatures around 100° Fahrenheit. A sample of cream
T in this condition is difficult to handle, since fat will rise to the l
surface so rapidly after mixing that the securing of a repre-  
sentative sample for the nine-gram charge is difficult. The best ’
way to treat an oily sample is to warm to ll0° F., and then T
- emulsify the mixture by hard shaking for a few seconds. As '.
rapidly as possible thereafter, weigh out the charge for test.  
, It is recommended that duplicate tests be made when oily  
. Y samples are dealt with. i
T Curdy Samples. Samples containing curd or elabber are , '
` very common in summer and are the cause of many incorrect *6
tests. The operator ’s problem is to break up the lumps as fine ii
é as possible. lf the curd is tough, pour through a small coarse- I
h mesh coffee strainer and press thru with the Hngers the curd rc- `
maining_in the strainer. Mix the sample well and weigh out `
` ' nine grams before the curd settles to the bottom of the jar. l
T   it
|‘ .

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E
ii ii 16 Kentucky Agricultural Experiment Station i`
4 CREAM FOR THE TEST. '
Cream must be weighed into the test bottles, not measured. v_
It is viscous and does not flow well from a pipette; besides, a t
A given volume of cream varies in weight according to its richness; I i`
17.6 c.e. of cream, for instance, might vary in weight from 17.2 l
{ I- ` grams to 18.0 grams, depending on its fat content and the E
l -»   amount of air that is mixt with it. The lawful amount of cream i
to use in testing is 9 grams.
‘: CREAM BALANCES. i
~· The cream balance, or scale used in weighing the cream for
testing, is a delicate mechanism and should be properly used and
  cared for. Any factor affecting the accuracy of scales will like- p
p   wise affect the correctness of tests. The scale should be con-
  veniently placed in the testing room, and should be on a firm
f foundation not subject to vibration. Light, unsteady tables are
i   especialy to be avoided, as scales are often thrown out of balance
  by a hand resting on the table or by a person standing near one
. .. of the supports. Operators should be provided with a small
- ,` pocket level so that the scales may at all times he l