at this secures more of the "high, quick" flavor wanted
in the market. On the average, cream is ripened to about 0.5 to 0.65 per
cent. acidity, a higher percentage than this giving a strong-flavored
butter. In the determination of acidity, the most convenient method is
to employ the Farrington alkaline tablet, which permits of an accurate
and rapid estimation of the acidity in the ripening cream. The amount of
acidity to be produced must of necessity be governed by the amount of
butter-fat present, for the formation of acid is confined to the serum
of the cream; consequently, a rich cream would show less acid by
titration than a thinner cream, and still contain really as much acid as
the other. The importance of this factor is evident in gathered-cream
factories.

The rate of ripening is dependent upon the conditions that affect the
rate of growth of bacterial life, such as time and temperature, number
of organisms in cream and also the per cent of butter fat in the cream.
Some years ago it was customary to ripen cream at about 50 deg. to 60 deg.
F., but more recently better results have been obtained, it is claimed,
where the ripening temperature is increased and the period of ripening
lessened. As high a temperature as 70 deg. to 75 deg. F. has been
recommended. It should be said that this variation in practice may have
a valid scientific foundation, for the temperature of the ripening cream
is undoubtedly the most potent factor in determining what kind of bacteria
will develop most luxuriantly. It is well known that those forms that
are capable of producing bitter flavors are able to thrive better at a
lower temperature than some of the desirable ripening species.

The importance of this factor would be lessened where a pure culture was
used in pasteurized cream, because here practically the selected
organism alone controls the field.

It is frequently asserted that better results are obtained by stirring
the cream and so exposing it to the air as much as possible. Experiments
made at the Ontario Agricultural College, however, show practically no
difference in the quality of the butter made by these two methods. The
great majority of the bacteria in the cream belong to the facultative
class, and are able to grow under conditions where they are not in
direct contact with the air.

~Flavor and aroma.~ The basis for the peculiar flavor or taste which
ripened cream-butter possesses is due, in large part, to the format