FOURTH ANNUAL YEAR BOOK — PART V. 319 



pared from skim milk has lost some of the rich, soft taste, but has a 

 cleaner acid taste. The very fact that a starter prepared from whole 

 milk has a more desirable taste when first prepared is not necessarily 

 an indication that it will produce better results as a starter for cream 

 ripening. From what we now know concerning starters, the ferments 

 which develop in the milk serum are those which are desirable in the 

 production of butter flavors. 



It is a well known fact, that just al)out the time when milk begins to 

 turn sour, that is when the sourness can be recognized by the taste, it 

 has a rather disagreeable flavor. After more acid develops the undesir- 

 able flavor largely disappear, and the milk assumes a clean desir 

 able acid taste. The reason for this has recently been accounted for by 

 Storch, the well known authority on starters. He claims to have proven 

 that those disagreeable flavors are due to certain undesirable organisms, 

 developing some acid and a great deal of other undesirable products in 

 the milk during the first souring stage. As the souring proceeds these 

 germs are subdued and gradually crowded out by the desirable acid pro- 

 ducing types. 



In the preparation of a starter the probabilities are that some of 

 these undesirable types of germs are present, at least it is safer to go on 

 the assumption that they are present. This makes the question of under- 

 ripening of starters just as important to guard against as the over-ripen, 

 ing. Starters which have been under-ripened by cooling too early for 

 several successive days assume a watery, flat, disagreeable taste, and if 

 used for the ripening of cream produces poor results. 



Finally a few general remarks as to cream ripening. When a good 

 starter has been prepared there should be no fear that it will produce 

 undesirable results, when added to the cream, provided the proper pre- 

 cautions are taken during the ripening process. The same precautions 

 in regard to "over-ripening" and "under-ripening" are as important In 

 the ripening of cream as in the preparation of the starter. By measuring 

 the degree of acidity in the cream by Mann's or Farrington's test, the 

 proper ripening stage can readily be determined. This will vary accord. 

 ing to different percentages of fat in the cream. 



The rapidity of ripening depends chiefly upon the ripening tempera- 

 ture and the amount of starter used. According to results obtained by 

 investigators, the greatest relative growth of the desirable germs is 

 obtained at a comparatively low temperature, namely about 65 degrees 

 Fahrenheit, The amount of starter which has been recommended to 

 add ranges between 5 and 40 per cent of the cream to be ripened. With- 

 out going into detail the amount of starter to use depends chiefly upon 

 the following factors: (1) the quality of the cream (pasteurized or un- 

 pasteurized, fresh or old, thick or thin, good or poor cream); (2) upon 

 the time when the ripening should be completed; (3) upon general cream- 

 ery conditions. A very large starter has in many instances been recom- 

 mended for thick cream, but as a rule better results are obtained if a 

 normal amount of starter (from 10 per cent to 15 per cent) is added, 

 together with some of the best milk that can be obtained, and then ripen 

 ■all of it together. 



