678 EXPERIMENT STATION RECORD. 



problems aud suggestions, for the imrpose of reuiiiHling the creamery mau of 

 essential matters concerned in the manufacture of a uniform product. The 

 topics treated are the factors that influence the overrun, making starters, color- 

 ing aud salting, and testing for acidity and moisture. 



Creamery butter, C. Larsen, T. H. Lund, and L. F. Miller (tioutli Dakota 

 Sta. Bill 122, pp. 699-130, figs. 6).— This bulletin, which is a continuation of 

 work previously noted (E. S. R., 22, p. 579). reports an investigation on the 

 factors affecting the acidity of creamery butter, and discusses the acidity test 

 as a measure of the deterioration of creamery butter. Suggestions are offered 

 on handling cream and cream separators. 



The factorsaffecting the acidity of butter which were studied were the amount 

 of washing the butter, the pasteurization of cream, the amount of salt in the 

 butter, the acidity of the cream, aud the temperature at which the butter was 

 held. The average acidity of the thoroughly washed butter when made was 

 equivalent to 0.3 cc. of tenth-normal alkali per 10 gms. of butter, less than that 

 of little washed butter. At the end of IG weeks this difference had increased 

 only to 0.5 cc. It is stated that these results should not lead one to believe that 

 it is not essential to wash thoroughlj^ butter made from hand-separated cream, 

 as this is of great importance in order to remove undesirable flavors, lessen 

 the danger of mottles, and produce a clear brine in the butter. 



"The butter made from the pasteurized cream did not increase in acidity as 

 rapidly as did the butter made from raw cream. The average difference when 

 made amounted to only 0.1 cc, but after the butter had been kept 16 weeks, 

 this difference had increased to 1.1 cc. During the 10 weeks the acidity of 

 the pasteurized cream butter had only increased 0.6 cc. as compared with au 

 increase of 1.6 cc. in the raw cream butter." 



" The average increase in the acidity of low salted butter during the 16 

 weeks is 4.7 cc, while the average increase in the acidity of the highly salted 

 butter is only l.G cc. the former being about three times as great as the latter. 

 The longer time the butter is kept the greater is this difference." 



" The average difference in the acidity of the high aud low salted butter when 

 fresh is 0.2 cc, and the average difference when G weeks old was .3.3 cc" 

 . " The average results show that the butter made from the ripened cream, 

 immediately after churning, contained 1 cc. more acid than did the butter 

 made from the sweet cream. At the end of the 16 weeks the ripened cream 

 butter contained 1.4 cc. more acid than did the sweet cream butter. During 

 the whole 16 week period the acidity of the butter from the ripened cream in- 

 creased 2.2 cc, while the acidity of the butter from the sweet cream increased 

 only l.S cc" 



" These results indicate that butter from fresh and properly ripened cream 

 not over one day old keeps better than does butter made from sweet cream. 

 The butter fat from very fresh cream is apparently in a more stable condition 

 than is the fat in the sour cream over one day old, and not so predisposed to 

 decomposition. It indicates that butter fat. in the form of butter, keeps better 

 than does butter fat in the form of cream, even though it be in properly ripened 

 cream." 



The butter kept at 50 to 60° F. gained 6.4 cc in acidity during the 12 weeks, 

 while the butter kept at 70 to 80° F. gained 10 cc. Butter kept 16 weeks was 

 tested at intervals of 4 weeks and compared with a score as estimated by a 

 competent judge. 



" During the whole 16 week period the butter was kept there was an aver- 

 age decrease in quality of the butter of 11.4 points, and an average increase in 

 acidity of 1.64 cc. This equals 0.144 cc. increase in acidity to one point de- 

 crease in the score. . . . The acid test gives practically the same results in 



