cream is heated to a higher temperature than is whole milk because the cream has a
high milkfat content, 32 to 40 percent.
b. Starter. After pasteurization of the cream, it is cooled and placed in storage
tanks until it is to be churned. Since high-quality cream may produce a butter with a flat
taste, the cream may be aged or ripened. This is a delicate operation since the amount
of culture and length of time required for culturing must be exact for proper ripening.
The usual procedure is to place the cream in a vat-type pasteurizer and heat it to about
70F (21C) which is the incubation temperature of the culture or starter. A culture of
desirable organisms known as a starter is added to the cream and the cream is gently
agitated to assure even distribution of the organisms. The starter used is normally a
strain of Streptococcus lactis. The cream is incubated for 4 to 5 hours prior to churning.
The cream is brought to a temperature of 46 to 48F (8 to 9C) in summer and 54 to
56F (12 to 13C) in winter before it is put into the churn.
c. Churning. Churns can be classified according to the materials used in their
construction; that is, metal churns or wooden churns. The purpose of churning is to
convert the fat-in-skim milk emulsion to a water-in-fat suspension. This is accomplished
by agitating the cream to form large fat globules and finally large masses of butter.
Churning usually requires 30 to 45 minutes. An accepted theory of churning is that
agitation of the cream causes the fat globules to strike one another and adhere. As the
agitation continues, the fat globules become larger and larger and the natural buttermilk
is gradually set free until the fat and serum portion of the cream are completely
separated. After the butter has formed in the churn, the buttermilk is removed.
d. Washing. After the buttermilk has been drawn off, the butter in the churn is
washed with potable water to remove any remnants of buttermilk which adhere to the
butterfat, to control the body and texture of the butter, and to aid in controlling the
composition of the butter. The amount of water added to the churn should equal the
volume of buttermilk withdrawn. The temperature of the water should be 2 to 4F lower
than that of the buttermilk drawn off.
e. Salting and Working. Salt is added to the butter just before working. Sweet
butter is butter with no salt added. Also, a certified coloring may be added to the butter
to maintain a constant color throughout the year and to satisfy the market demand. The
butter is worked in order to evenly distribute the salt and butter coloring that may have
been added, to produce a more compact mass of butterfat, and to expel excess
buttermilk and water. Working is accomplished within the churn by the action of rolls or
baffels which pick up the butter and drop it to the bottom of the churn.
f. Printing and Packing. After the butter has been worked, it is removed from
the churn, placed in bulk containers, and put in storage at 40F (4C) or less to harden
prior to printing. Butter may be printed in the plant where it was churned or shipped to
another plant to be printed. The bulk butter, chilled or tempered to assure the
necessary degree of firmness, is removed from its container and the bulk blocks cut into
smaller blocks which can be placed in the hopper of the printing machine. In the printer,