BUTTER OVERRUN 277 
yield about one-half pound more of butter than the same 
amount of fat in a 20 per cent cream; in other words, the 
overrun from a 35 per cent cream will be one-half per 
cent greater than that from a 20 per cent cream. 
Mechanical Losses. By mechanical losses is meant 
the small losses of cream remaining in cans, vats, strain- 
ers, etc., and the butter particles remaining in the churns 
and on the packers, butter spades, etc. Where care is 
exercised in properly rinsing the cans and ripeners and 
in the-handling of the butter, losses from this source will 
be rather slight. On the other hand, carelessness in 
these matters may result in heavy losses and in a material 
lowering of the overrun. 
Correct Reading of Tests. It is very evident that 
a little too high or a little too low a reading will mate- 
rially affect the overrun. If a cream whose actual test is 
30 per cent should be read only 29 per cent, the overrun 
will be abnormally increased by approximately 4.0 per 
cent. It is easy to make a mistake of one per cent in 
the reading of cream tests and, what is worse, many 
cream tests are purposely read too low so as to enable 
the creameryman to show a big overrun. It is to every 
creameryman’s interest to read tests accurately, because 
inaccuracies are bound to be discovered sooner or later 
and may lead to the disruption of the creamery. 
Average Overrun. The overrun from whole milk 
averages 18%, that from cream 20%. 
