Butter and Butter Products 203shelf life and bacteriological quality). The
impact of butter making technology on the
microstructure of butter has been described
in detail by Fearon and Golding (2008).
A continuous butter making machine from
APV Unit Systems, Denmark, is shown in
Figure 9.3 ; the capacity of such equipment
ranges from 500 kg/hour to 12,000 kg/hour,
and their fl exibility enables sweet, cultured,
or whey creams with a range of fat contents
Figure 9.2. Batch butter churn (APV Unit Systems,
Denmark). Fearon and Golding (2008).
Figure 9.3. Continuous butter making machine (APV Unit Systems, Denmark). Fearon and Golding (2008).
to be churned, as well as dairy blends of
cream mixed with vegetable oil. Greater
operating detail may be seen in the schematic
outline of the machine in Figure 9.4. The
machine is divided into three sections: churn-
ing, separating, and working.Churning Section
The churning section consists of a horizontal
cylinder and a multi - bladed beater that sits
only a few millimeters from the cylinder
wall. Aged cream at the desired churn tem-
perature is pumped into the rear end of the
churning cylinder, where the beater, operat-
ing at speeds of approximately 1,000 to
1,500 rpm, introduces air into the cream,
damages the fat globule membrane, and
causes the globules to agglomerate. Selection
of beater speed and speed constancy is
important to achieve lowest fat loss into the
buttermilk and highest moisture content of
the buttermilk. The size and moisture content
of the butter grains as well as the fat content
of the buttermilk are largely determined
by the speed of the beater. Butter grains must
be of a size to allow good drainage of the