Vermont phÅ“nix. [volume] (Brattleboro, Vt.) 1834-1955, 1880-05-28
Crenm---its Propertics-.-HOu and
WIN IL Rfses.
from Notes Of Prof Arnolds Lectures on Dairy
Farming at Cornell DIVERSITY

IFrom Notes Of Prof. Arnold's Lectures on Dairy
Farming at Cornell Uuyerstyl
Cream exists in milk as soid--solid fats.
1t is in form Of globules both large and small
These globules are surrounded by a pellicle
of membrane. The composition of these
globules differs greatly with breed of animals.
There are several varieties of fats in these
globules and each is supposed to be separate
from the rest. The pellicle has n greater
specific gravity than the contents, and rs
there is difference in the proportion between
the amounts of each, some cream rises quick
or than other Large globules rise quicker
than small ones, because the membrane sur
rounding them is stretched more and thus
thinner. Some of the small globules are left
in skim milk because there is greater resist
ance TO their rising in proportion to bulk.
When an animal is well fed on rich food there
are more fats in the milk, the globues are
larger, and the cream will rise quicker The
large globules make the better butter, per-
haps because there is less pellicle. Skim
milk is considerably heavier than water, so
when water is added to milk there is less diff
ference between the specific GRANTEES of the
cream and the rest of the mixture, so it rises
more slowly, and not so thoroughly as in
pure milk When cream rises it usually has
some milk with it, therefore it is sometimes
heavier than water but when pure it is light
err. We call the cream solid, but it contains
about 60 per cent Of water and 40 per cent.
Of solid matter about 80 per cent is nitro
genous matter. The size of globules varies
with different breeds, being dependent on
the size of the gland cells of the ami
NAL. The thickness of the layer of cream
which rises is dependent on the size of
globules. If all are large the layer is thick,
because spaces are left between them but if
some large and some small, they settle in
more cOmpactly, and thus we have more sub
stance in given space. II the milk was
chilled suddenly, much of it would come up
with the cream. Fats shrink and swell more
with cold and heat than water, but if we heat
milk the water will take the heat first and so
the cream will not rise any more rapidly but
if we stop heating at 1907, or any high tenn
perature the cream will not rise rapidly II
we cool suddenly the water contracts first, so
1t leaves the cream on top. II milk is TO
stand in cold water, it should be in vessels at
least foot deep. The warmer the tempera-
ture the more shallow it may be set it de
ponds somewhat upon the rate at which the
temperature changes. BY mixing the milk
of different breeds the cream is more solid
but they do not churn alike. In warm set
ting there is some danger Of the germs which
are apt to be in milk developing, being aided
by heat These hinder the rising of, cream
and are detriment to its quality But if the
milk is heated to 100 the germs will all be
killed. Scalding also removes the odors, and
makes the cream very pure. The milk should
stand sometime before scaldng to allow the
germs to start The centrifugal machine
separates the cream by revolving rapidly, be-
ing so shaped that the cream flies over the
top and skim milk in another direction This
process gives the cream a thorough airing,
which removes the odors, and the cream can
be separated as soon rs MIXED. Still the
cream has to be ripencd before it can be
made into butter. This ripening is the re-
suit of the oxidation of the pcllices surround
ing the fat globules BY using tightly closed
vessels this oxidation is prevented, and the
odors are also prevented from escaping.
! HUSb