236 IOWA DEPARTMENT OF AGRICULTURE. 



Of course everything was favorable; the cream was ripe, there was a great 

 deal of butter fat there, so that it was ready for this particular change to 

 bring the butter fat together so that the particles stuck and made lumps of 

 butter so large that could not be held in suspension any longer but rrse to 

 the surface, and there appeared in about a pint jar of cream a lump of but- 

 ter that filled the jar quarter full. 



So this is one of the changes occurring in the freezing of milk, and where 

 a quantity of butter gets separated in this way it is undoubtedly a loss. 1 

 think it is not a very considerable loss, but it is interesting to know this 

 because it is something you can observe here and there. I am explaining 

 this because I want to assert the general proposition that freezing does not 

 have any very noticeable efifect upon the milk, and that it is not injurious to 

 the milk where it is to be used for any ordinary purpose. I mean that it 

 does not alter in any way or lessen the value of the product that is to be 

 made from the milk. I do not mean that it has economical value; that is an 

 entirely different question; but it is not injurious to the quality of the milk 

 in other ways. We are not aware of any change in the quality of the milk, 

 and this same statement can be applied to cream with equal validity. 



The effect of cold upon souring the milk, of course, is very well known. 

 Cold in a marked degree makes the milk keep longer, prevents souring, 

 prevents the development ,of any of those flavors that are developed in the 

 milk after it is drawn. I think freezing has no effect upon flavors that the 

 milk already contains. The greater degree of cold the less fermentation 

 there is in the milk, and in the neighborhood of the freezing point, that is, 

 a little above the freezing point, there is practically no fermentation, and at 

 the freezing point and below there is none so far as we can measure it by 

 our ordinary means, by the senses, and in an ordinary reasonable length of 

 time, say several weeks. By the way, this freezing of milk is the method 

 that is used for preserving milk where it is shipped long distances, or has to 

 be kept a long time. I am told it is the method used on large steamers that 

 cross the ocean; the milk is frozen and kept in that condition and when 

 thawed it is just as valuable as it was before it was frozen. There are no 

 spontaneous chemical changes taking place in the milk and there can be no 

 bacterial changes at these low temperatures, so the effect of freezing is to 

 prevent souring of the milk and prevent the development of any flavor 

 whatever. 



While we are still dwelling upon this question of freezing the milk, I think 

 it would be of interest to look at it from two standpoints. I am told by but- 

 termakers, and 1 believe it myself, that it takes as much steam to warm 

 frozen milk to a separating temperature as it does to run the separator to 

 separate that milk, and we all know that it takes a good deal of coal to run 

 the creamery and run the separators, so the amount of steam necessary to 

 thaw frozen milk and separate it is naturally considerable, and it may, 

 therefore, not be economical to freeze the milk, especially if the patrons can 

 be instructed and induced to take good care of it and keep it in good con- 

 dition without letting it freeze, it is more economical to have them do that 

 than to have them let it freeze and bring it to the creamery in that condition, 

 to say nothing about the extra work and annoyance of having to thaw milk 

 before you can empty it into the weigh can. 



