182 CoNDENSED BurreRMILK 
During the early stages of the condensing process the but- 
termilk boils and behaves in the pan in a similar manner as 
milk. As the process continues and the buttermilk increases 
in density, it becomes more sluggish and does not circulate as 
rapidly, nor boil as vigorously. 
Concentration.—The buttermilk should be condensed until 
it has a concentration of at least 4:1. Buttermilk of a lower con- 
centration fails to have the necessary keeping quality to with- 
stand the trials of storage for several months at ordinary tem- 
perature. It undergoes decomposition, usually of the putrefac- 
tive type, that renders it unfit for feeding purposes. 
Testing for Density—No accurate mechanical method of 
determining the exact density of the condensed buttermilk has 
as vet been worked out. \When a concentration of about 4:1 
or more has been reached, the buttermilk is very thick, even 
while hot. It is too thick and viscous to permit of testing it 
with the Beaumé hydrometer. ‘The density could be determined 
however by weighing a definitely measured volume or by the 
adaption of a resistance tester such as the Mojonnmier viscosi- 
meter. Ordinarily, however, the determination of the proper 
degree of concentration is left to the experienced eye and judg- 
ment of the pan operator. If he condenses batches of uniform 
size, the height of the surface of the condensed buttermilk in 
the pan furnishes an approximate guide. ‘The behavior of the 
boiling condensed buttermilk, when the proper degree of concen- 
tration has been reached, is also noted. And samples taken 
from the pan and examined for thickness, standing-up properties 
and transparency or opaqueness, as described under ‘* Methods of 
Striking” for sweetened condensed milk, Chapter VI, enable the 
operator to approach a fairly uniform density of the finished 
product from batch to batch. 
When condensed at the ratio of 4:1 the buttermilk at the 
temperature of the pan, or about 120 degrees F., is thick enough 
so that when a sample is taken into a cup and a portion of it 
is picked up with a spoon or stick and is allowed to drop back 
into the cup from a height of about six inches, it does not readily 
diffuse, but “piles up” on the surface of the sample in the cup. 
Condensing Buttermilk by Film Process.—’lhe condensing 
of buttermilk can be and is accomplished also by film evapora- 
